bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study of compressibility effects in the
high-speed turbulent shear layer using
direct simulation
Authors: PANTANO C. , SARKAR S. 
Published: August 2008

Direct simulations of the turbulent shear layer are performed for subsonic to supersonic
Mach numbers. Fully developed turbulence is achieved with profiles of mean
velocity and turbulence intensities that agree well with laboratory experiments. The
thickness growth rate of the shear layer exhibits a large reduction with increasing
values of the convective Mach number, Mc. In agreement with previous investigations,
it is found that the normalized pressure–strain term decreases with increasing Mc,
which leads to inhibited energy transfer from the streamwise to cross-stream fluctuations,
to the reduced turbulence production observed in DNS, and, finally, to reduced
turbulence levels as well as reduced growth rate of the shear layer. An analysis, based
on the wave equation for pressure, with supporting DNS is performed with the result
that the pressure–strain term decreases monotonically with increasing Mach number.
The gradient Mach number, which is the ratio of the acoustic time scale to the flow
distortion time scale, is shown explicitly by the analysis to be the key quantity that
determines the reduction of the pressure–strain term in compressible shear flows. The
physical explanation is that the finite speed of sound in compressible flow introduces
a finite time delay in the transmission of pressure signals from one point to an
adjacent point and the resultant increase in decorrelation leads to a reduction in the
pressure–strain correlation.The dependence of turbulence intensities on the convective Mach number is investigated.
It is found that all components decrease with increasing Mc and so does the
shear stress.DNS is also used to study the effect of different free-stream densities parameterized
by the density ratio, s = ρ2/ρ1, in the high-speed case. It is found that changes in the
temporal growth rate of the vorticity thickness are smaller than the changes observed
in momentum thickness growth rate. The momentum thickness growth rate decreases
substantially with increasing departure from the reference case, s = 1. The peak value
of the shear stress, uv, shows only small changes as a function of s. The dividing
streamline of the shear layer is observed to move into the low-density stream. An
analysis is performed to explain this shift and the consequent reduction in momentum
thickness growth rate.
Missing in action: verbal metaphor for information technology
Authors: Bruthiaux Paul 
Published: August 2008

The rapid spread of Information Technology (IT) in recent years and the role it plays in many aspects of our lives has not left language use untouched. A manifestation of this role is the degree of linguistic creativity that has accompanied technological innovation. In English, this creativity is seen in the semantic relabeling of established terms such as web, bug, virus, firewall, etc. Another strategy favored by IT lexifiers is the use of lexical items clustered in heavy premodifying groups, as in random access memory, disk operating system, central processing unit, and countless others (White, 1999). In brief, IT technology – and in particular, the World Wide Web – has made it possible for users to break free of many linguistic codes and conventions (Lemke, 1999).For the linguist, the happy outcome of the spread of IT is that it has created an opportunity to analyze the simultaneous development of technology and the language that encodes it and the influence of one on the other (Stubbs, 1997). To linguists of a broadly functional disposition, this is a chance to confirm the observation that scientific language differs substantially from everyday language. More importantly, it is also a chance to verify the claim made chiefly by Halliday & Martin (1993) that this difference in the characteristics of each of these discourses stems from a radical difference between scientific and common sense construals of the world around us.
A study of infectious intestinal disease in England: risk factors associated with group A rotavirus in children
Authors: SETHI D. , CUMBERLAND P. , HUDSON M. J. , RODRIGUES L. C. , WHEELER J. G. , ROBERTS J. A. , TOMPKINS D. S. , COWDEN J. M. , RODERICK P. J. 
Published: August 2008

Objective: To identify risk factors for infectious intestinal disease (IID) due to rotavirus group A in children aged under 16 years.Methods: Case-control study of cases of IID with rotavirus infection presenting to general practitioners (GPs) or occurring in community cohorts, and matched controls.Results: There were 139 matched pairs. In children under 16 years the following risk factors were significantly associated with rotavirus IID: living in rented council housing (adjusted OR=3·78, P=0·022), accommodation with more than five rooms (OR=0·72, P=0·002), contact with someone ill with IID (OR=3·45, P<0·001). Some foods were associated with decreased risk. In infants, bottle feeding with or without breast feeding was associated with increased risk (OR=9·06, P<0·05).Conclusions: Contact with persons with IID, living in rented council housing and accommodation with fewer rooms, were significant risk factors for sporadic rotavirus IID in children whereas breast feeding is protective in infants.
Epidemiology of meningococcal meningitis in Angola, 1994–2000
Authors: GASPAR M. , LEITE F. , BRUMANA L. , FÉLIX B. , STELLA A. A. 
Published: August 2008

We describe six meningococcal disease outbreaks that occurred in Angola during the period 1994–2000. In total, 7140 cases were documented. The age groups most affected were 15–29 years and 5–14 years; there were no differences in incidence between the sexes. Circulation of both serogroup A and sporadic serogroup B strains was demonstrated. Mass vaccination campaigns with A+C meningococcal polysaccharide vaccine were implemented, except in Yambala province in 1999 where insecure conditions precluded this intervention.Outbreaks of serogroup A meningococcal disease in Angola may indicate an extension of these epidemics outside the meningitis belt. Mass vaccination campaigns stopped the Angolan epidemics within weeks. Civil conflict and displaced persons living in crowded areas created serious difficulties for surveillance and impeded timely public health responses.
Transmission dynamics and mechanisms of endemicity of scrapie in the UK sheep population
Authors: TRUSCOTT J. E. , FERGUSON N. M. 
Published: August 2008

SUMMARYScrapie is a fatal neurological disease of sheep which is endemic in the United Kingdom. It is one of the family of transmissible spongiform encephalopathies (TSEs) that includes BSE. In this paper, we developed a micro-simulation model for scrapie in the UK sheep population, incorporating the genetic and structural diversity of the population and infectious contact between flocks through trading. The simulation was fitted to epidemiological data from a range of sources. We found a detection/reporting probability of 16% (95% CI 12–17) for animals dying of scrapie. Prevalence of infected animals in the population was about 0·15%. Infected individuals were found in 9% of flocks overall, rising to 60% in Shetland and 75% in Swaledale flocks. Mean values of R0 for flocks varied with breed from 2·43 (Shetland) to 0·21 (Suffolk). We also examined the possible long-term persistence of scrapie in the UK flock in the absence of any intervention.
Control of scrapie in the UK sheep population
Authors: TRUSCOTT J. E. , FERGUSON N. M. 
Published: August 2008

SUMMARYScrapie is a fatal transmissible spongiform encephalopathy (TSE) of sheep, endemic in the UK for centuries. Interest in the disease has been heightened over the last decade by the possibility of the related BSE being transmissible to and between sheep and a range of control interventions has been proposed and implemented. In this paper, we examined the effect of these policies and their components on observed case rate, susceptible allele frequency and R0 within the framework of a large simulation model of the British sheep population and its breeding and trading structure. We compared interventions with the natural fade-out of scrapie in the population through loss of susceptible genotypes in the absence of control. We compare the results of interventions with the natural course of the scrapie epidemic. Our model suggested that scrapie will persist in the national flock for 300–400 years with the impact on gene frequencies confined largely to high case-rate breeds, such as Shetland and Swaledale. We found the National Scrapie Plan (NSP) to be the most effective in terms of the removal of both susceptible genotypes and scrapie from the population. Complete eradication of scrapie can be achieved within 32 years (95% CI 23–43 years). The Compulsory Scrapie Flock Scheme (CSFS) is as effective as the NSP in reducing the observed case rate but has a limited impact on the frequencies of susceptible genotypes in the population overall. In combination with the NSP, eradication of scrapie is achieved >10 years faster. Of the components of the CSFS, the breeding and culling aspects are each almost as effective as the full policy, with trading restrictions contributing little. We have speculated on the impact of control measures on the possibility BSE infection within the national flock by examining their effect on flock R0 for BSE across different breeds.
Molecular analysis of high-level ciprofloxacin resistance in Salmonella enterica serovar Typhi and S. Paratyphi A: need to expand the QRDR region?
Authors: CAPOOR M. R. , NAIR D. , WALIA N. S. , ROUTELA R. S. , GROVER S. S. , DEB M. , AGGARWAL P. , PILLAI P. K. , BIFANI P. J. 
Published: August 2008

SUMMARYFourteen strains of S. Typhi (n=13) and S. Paratyphi A (n=1) resistant to ciprofloxacin were compared with 30 ciprofloxacin decreased-susceptibility strains on the basis of qnr plasmid analysis, and nucleotide substitutions at gyrA, gyrB, parC and parE. In ciprofloxacin-resistant strains, five S. Typhi and a single S. Paratyphi A showed triple mutations in gyrA (Ser83→Phe, Asp87→Asn, Glu133→Gly) and a novel mutation outside the quinolone resistance determining region (QRDR) (Met52→Leu). Novel mutations were also discovered in an isolate (minimum inhibitory concentration 8 μg/ml) in gyrA gene Asp76→Asn and outside the QRDR Leu44→Ile. Out of 30 isolates with reduced susceptibility, single mutation was found in 12 strains only. Genes encoding qnr plasmid (qnr A, qnr B, AAC1-F) were not detected in ciprofloxacin-resistant or decreased-susceptibility strains. Antimicrobial surveillance coupled with molecular analysis of fluoroquinolone resistance is warranted for reconfirming novel and established molecular patterns of resistance, which is quintessential for reappraisal of enteric fever therapeutics.
Differences in the susceptibility of dromedary and Bactrian camels to foot-and-mouth disease virus
Authors: LARSKA M. , WERNERY U. , KINNE J. , SCHUSTER R. , ALEXANDERSEN G. , ALEXANDERSEN S. 
Published: August 2008

SUMMARYIn this study, two sheep, eight dromedary camels and two Bactrian camels were inoculated with foot-and-mouth disease virus (FMDV) type A SAU 22/92. Five naive dromedary camels and four sheep were kept in direct or indirect contact with the inoculated camels. The inoculated sheep, which served as positive controls, displayed typical moderate clinical signs of FMD and developed viraemia and high antibody titres. The presence of the virus was also detected in probang and mouth-swab samples for several days after inoculation. In contrast, the inoculated dromedary camels were not susceptible to FMDV type A infection. None of them showed clinical signs of FMD or developed viraemia or specific anti-FMDV antibodies despite the high dose of virus inoculated. All the contact sheep and contact dromedaries that were kept together with the inoculated camels remained virus-negative and did not seroconvert when tested up to 28 days post-inoculation (p.i.). In comparison with the non-susceptible dromedaries, the two inoculated Bactrian camels showed moderate to severe clinical signs of FMD; however, the clinical signs of FMD appeared rather late, between 8 and 14 days p.i., compared to the inoculated sheep. Characteristic FMD lesions in the Bactrian camels, accompanied with severe lameness, were only observed on the hind feet. The presence of the virus in the serum samples of both Bactrian camels was detected by real-time RT–PCR in one of the animals on days 3 and 7 p.i. and in the second animal from days 1 to 3 p.i. and subsequently again on day 21 p.i. The Bactrian camels developed high titres of antibodies to the inoculated FMDV which appeared at 7–10 days p.i. and lasted up to 130 days p.i. Only low and transient amounts of FMDV were detected in the mouth-swab and probang samples collected from both Bactrian camels.
An outbreak ofSalmonellaTyphimurium 9 at a school camp linked to contamination of rainwater tanks
Authors: FRANKLIN L. J. , FIELDING J. E. , GREGORY J. , GULLAN L. , LIGHTFOOT D. , POZNANSKI S. Y. , VALLY H. 
Published: August 2008

SUMMARYIn March 2007, an outbreak of gastroenteritis was identified at a school camp in rural Victoria, Australia, affecting about half of a group of 55 students. A comprehensive investigation was initiated to identify the source. Twenty-seven attendees were found to have abdominal pain, diarrhoea and nausea (attack rate 49%). Of 11 faecal specimens tested all were positive forSalmonellaTyphimurium definitive phage type 9 (DT9). Of four samples taken from the untreated private water supply, two were positive for DT9. Drinking water from containers filled from rainwater tanks [relative risk (RR) 3·2,P=0·039] and participation in two recreational activities – flying fox (RR 5·3,P=0·011), and beam-balance (RR 3·9,P=0·050) – were indicative of a link with illness. Environmental and epidemiological investigations suggested rainwater collection tanks contaminated with DT9 as being the cause of the outbreak. Increased use of rainwater tanks may heighten the risk of waterborne disease outbreaks unless appropriate preventative measures are undertaken.
Variance in protegular size: a correlate of larval trophic mode in Early Palaeozoic brachiopods
Authors: Freeman Gary , Lundelius Judith W. 
Published: August 2008

ABSTRACTThe size of the protegulum on the valves of Early Palaeozoic rhynchonelliform brachiopods has previously been used as a criterion to assign various taxa to either a planktotrophic or a lecithotrophic larval mode. A more reliable quantitative character is evaluated in juvenile samples of two genera from the Ordovician Mifflin Formation, the presumed planktotrophic orthid Doleroides pervetus and the presumed lecithotrophic atrypid Protozyga nicolleti, using the coefficient of variation in measurements of protegular size. The Doleroides sample has a significantly higher coefficient of variation than does the Protozyga sample. The results are in accord with observations on living marine invertebrates which indicate that at settlement (when mineralisation of the protegular mantle in brachiopods occurs), planktotrophic larval size is more variable than larval size in lecithotrophs because of fluctuations in food availability and duration of the planktonic phase. This result confirms that protegular size variance can be used to make inferences about larval trophic mode.
Shell matrices of Recent rhynchonelliform brachiopods: microstructures and glycosylation studies
Authors: Gaspard Danièle , Marin Frédéric , Guichard Nathalie , Morel Sylvain , Alcaraz Gérard , Luquet Gilles 
Published: August 2008

ABSTRACTLike most metazoan biomineralisations, the brachiopod shell is the end product of a biologically controlled calcification process. The main agent of the control is the extracellular matrix, which is secreted by the outer mantle epithelium. This matrix mediates the calcification process by allowing crystal nucleation and elongation in specific orientations and finally, by stopping crystal growth. The proteinaceous moiety of brachiopod shell matrices has been extensively studied. Less known are the post-translational modifications that occur in these matrices, in particular glycosylations. In this comparison of five species of Recent articulated brachiopods, the ratio of soluble to insoluble organic matrix varies between the species. Polydisperse macromolecular materials occur in each of these species with discrete proteins of 50 kDa in Notosaria nigricans, Calloria inconspicua and Neothyris lenticularis, 37 kDa in Terebratulina retusa and Gryphus vitreus and 20–25 kDa in N. nigricans. Protein mixtures from all five species respond differently to anionic stains (Stains-All and Alcian Blue). PAS staining results in a positive smear in C. inconspicua and T. retusa and highlights low molecular weight glycoproteins in C. inconspicua. The polysaccharide composition of the soluble matrix of T. retusa is different from the others due to high proportions of arabinose and low proportions of fucose. In all cases, polysaccharide composition of the insoluble matrix is dominated by glucose and glucosamine. Insoluble matrices have more glucose and xylose and less galactosamine and glucosamine than the corresponding soluble matrix. Relatively high amounts of glucosamine may suggest the presence of chitin in the shell matrix of rhynchonelliform brachiopods.
Cryptic speciation in the Recent thecideide brachiopod Thecidellina in the Atlantic and the Caribbean
Authors: Lüter Carsten , Hoffmann Jana , Logan Alan 
Published: August 2008

ABSTRACTUltrastructural examination of the brachiopod Thecidellina from three different locations in the Caribbean and the Atlantic revealed that at least three cryptic species are present. One is the type species of the genus, Thecidellina barretti, which may only occur in Jamaica. The other two, previously lumped into T. barretti, are new to science, viz T. bahamiensis Lüter & Logan sp. nov. from the Bahamas and T. williamsi Lüter & Logan sp. nov. from Cape Verde. All three species clearly differ not only in their provenance, but also in specific shell characters, such as spiculation of the ventral valve, presence of a ventral median ridge, shape of two holes in the intrabrachial ridge of the dorsal valve and the structure of the interbrachial lobes. The identification of three instead of a single species and their supposed allopatric speciation is discussed with regard to the thecideide life cycle and independent models of larval dispersal in the Caribbean, based on oceanographic data.
Pedicle preservation in a Silurian rhynchonelliformean brachiopod from Herefordshire, England: soft-tissue or an artefact of interpretation?
Authors: Bassett Michael G. , Popov Leonid E. , Egerquist Eva 
Published: August 2008

ABSTRACTThe interpretation of pedicle soft tissue preservation in a unique brachiopod specimen of Wenlock (Silurian) age from Herefordshire, western England, is re-assessed. Bethia serraticulma, assigned originally to the Orthida, is more probably a member of the Strophomenida (Plectambonitoidea). The supposed pedicle structure is more plausibly a weakly mineralised pedicle sheath, which is a common morphological and functional development in the early ontogeny of a number of Palaeozoic brachiopod lineages.
Columnar shell structures in early linguloid brachiopods – new data from the Middle Cambrian of Sweden
Authors: Streng Michael , Holmer Lars E. , Popov Leonid E. , Budd Graham E. 
Published: August 2008

ABSTRACTThe records of columnar shell structures of linguloid brachiopods (Class Lingulata, Order Lingulida, Superfamily Linguloidea) are reviewed in the light of the discovery of two new taxa from the Middle Cambrian Forsemölla Limestone Bed of southern Sweden. The linguloid taxa, described here as Eoobolus? sp. aff. E. priscus (Poulsen) and Canalilatus? simplex sp. nov., are both characterised by a columnar shell structure, a structural type that is representative for acrotretoid brachiopods and that has previously only rarely been reported from the linguloids. Though the two taxa are superficially similar to known genera, i.e., Eoobolus and Canalilatus, their shell structure challenges such affiliations, as the shell structure of the type species of these genera is previously unknown. Linguloid families whose morphological characteristics agree the most with those of the new taxa, i.e., the Zhanatellidae and the Eoobolidae, and from which columnar shell structures have been reported, i.e., the Lingulellotretidae and the Kyrshabaktellidae, are reviewed briefly. Many taxa assigned to these families completely lack shell structure data and are in need of restudy in order to elucidate their systematic position. Knowledge of the representative type of shell structure of the various suprageneric taxa within the Linguloidea is considered crucial, in order to unravel their currently poorly resolved phylogenetic relationships.
Crystallography of craniid brachiopods by electron backscatter diffraction (EBSD)
Authors: Pérez-Huerta Alberto , England Jennifer , Cusack Maggie 
Published: August 2008

ABSTRACTElectron backscatter diffraction (EBSD) is used to determine the detailed crystallographic orientation of calcite crystals of craniid brachiopods in the context of shell ultrastructure. Sections of shells of two Recent species, Novocrania anomala and Novocrania huttoni, are analysed to provide 3D crystallographic patterns at high spatial resolution. The c-axis of semi-nacre calcite crystals is oriented parallel to the laminae that define the ultrastructure of the secondary layer. This orientation differs from that of rhynchonelliform calcitic brachiopods where the c-axis is perpendicular to the length of morphological fibres and to the shell exterior.
Life habit and spatial distribution of siphonotretid brachiopods in the Lower Ordovician of the Prague Basin, Czech Republic
Authors: Mergl Michal , Kraft Jaroslav , Kraft Petr 
Published: August 2008

ABSTRACTSiphonotretid brachiopod distribution in the Lower Ordovician of the Prague Basin is described and discussed; the new species Alichovia cometa is established. The preservation and distribution of the group indicate a preference for shallow-water offshore, high-energy environments: siphonotretids are abundant shelly fossils in the shallower-water, mostly marginal sites of the basin but are absent in the deeper parts. Their environmental limits were complementary to those of the graptolites; siphonotretids co-occur with epiplanktonic graptolites at only a few localities. Deeper offshore deposits with biramose dichograptids and diverse, generally delicate benthic dendroids lack siphonotretids. Indeed, siphonotretids were intolerant to dysoxia and preferred a well-aerated siliciclastic, firm sea floor in the shallower parts of the basin. They were tolerant to suspended coarser detritus, using their spines which functioned as an effective sieve. The density and ramification of spines indicate three sifting strategies. Suggested life styles above the seabed on elevated surfaces (algae, sponges, dendroids) are not supported by direct evidence. They more likely lived within more supple and soft matrices (sponges, tufts of algae) stabilised by their spines, with the spinose basket maintaining free space for inhalant and exhalant currents.