bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of heat release on the energy exchange in reacting turbulent shear flow
Authors: LIVESCU D. , JABERI F. A. , MADNIA C. K.
Published: August 2008

The energy exchange between the kinetic and internal energies in non-premixed
reacting compressible homogeneous turbulent shear flow is studied via data generated
by direct numerical simulations (DNS). The chemical reaction is modelled by a one-
step exothermic irreversible reaction with Arrhenius-type reaction rate. The results
show that the heat release has a damping effect on the turbulent kinetic energy for
the cases with variable transport properties. The growth rate of the turbulent kinetic
energy is primarily in uenced by the reaction through temperature-induced changes
in the solenoidal dissipation and modifications in the explicit dilatational terms
(pressure–dilatation and dilatational dissipation). The production term in the scaled
kinetic energy equation, which is proportional to the Reynolds shear stress anisotropy,
is less affected by the heat release. However, the dilatational part of the production
term increases during the time when the reaction is important. Additionally, the
pressure–dilatation correlation, unlike the non-reacting case, transfers energy in the
reacting cases, on the average, from the internal to the kinetic energy. Consequently,
the dilatational part of the kinetic energy is enhanced by the reaction. On the contrary,
the solenoidal part of the kinetic energy decreases in the reacting cases mainly due
to an enhanced viscous dissipation. Similarly to the non-reacting case, it is found
that the direct coupling between the solenoidal and dilatational parts of the kinetic
energy is small. The structure of the flow with regard to the normal Reynolds stresses
is affected by the heat of reaction. Compared to the non-reacting case, the kinetic
energy in the direction of the mean velocity decreases during the time when the
reaction is important, while it increases in the direction of the shear. This increase
is due to the amplification of the dilatational kinetic energy in the x2-direction by
the reaction. Moreover, the dilatational effects occur primarily in the direction of the
shear. These effects are amplified if the heat release is increased or the reaction occurs
at later times. The non-reacting models tested for the explicit dilatational terms are
not supported by the DNS data for the reacting cases, although it appears that some
of the assumptions employed in these models hold also in the presence of heat of
reaction.
Stability of free-surface thin-film flows over topography
Authors: KALLIADASIS SERAFIM , HOMSY G. M.
Published: August 2008

We consider the stability of the steady free-surface thin-film flows over topography
examined in detail by Kalliadasis et al. (2000). For flow over a step-down, their
computations revealed that the free surface develops a ridge just before the entrance to
the step. Such capillary ridges have also been observed in the contact line motion over
a planar substrate, and are a key element of the instability of the driven contact line.
In this paper we analyse the linear stability of the ridge with respect to disturbances
in the spanwise direction. It is shown that the operator of the linearized system has
a continuous spectrum for disturbances with wavenumber less than a critical value
above which the spectrum is discrete. Unlike the driven contact line problem where an
instability grows into well-defined rivulets, our analysis demonstrates that the ridge is
surprisingly stable for a wide range of the pertinent parameters. An energy analysis
indicates that the strong stability of the capillary ridge is governed by rearrangement
of fluid in the flow direction flowing to the net pressure gradient induced by the
topography at small wavenumbers and by surface tension at high wavenumbers.
The two-sided lid-driven cavity: experiments on stationary and time-dependent flows
Authors: BLOHM CH. , KUHLMANN H. C.
Published: August 2008

The incompressible fluid flow in a rectangular container driven by two facing sidewalls
which move steadily in anti-parallel directions is investigated experimentally for
Reynolds numbers up to 1200. The moving sidewalls are realized by two rotating
cylinders of large radii tightly closing the cavity. The distance between the moving
walls relative to the height of the cavity (aspect ratio) is Γ = 1.96. Laser-Doppler and
hot-film techniques are employed to measure steady and time-dependent vortex flows.
Beyond a first threshold robust, steady, three-dimensional cells bifurcate supercritically
out of the basic flow state. Through a further instability the cellular flow becomes
unstable to oscillations in the form of standing waves with the same wavelength as the
underlying cellular flow. If both sidewalls move with the same velocity (symmetrical
driving), the oscillatory instability is found to be tricritical. The dependence on
two sidewall Reynolds numbers of the ranges of existence of steady and oscillatory
cellular flows is explored. Flow symmetries and quantitative velocity measurements
are presented for representative cases.
Inclined turbulent fountains
Authors: BLOOMFIELD LYNN J. , KERR ROSS C.
Published: August 2008

We present an experimental investigation of turbulent fountains produced when dense
fluid is injected upwards into either a homogeneous or a stratified environment at an
angle to the vertical. We determine the initial height above the source at which the
flow first comes to rest, the final height of the fountain, and the height at which the
mixed fluid finally intrudes when the environment is stratified. The initial fountain
height is found to decrease monotonically as the angle of inclination is increased. In
contrast, the final fountain height is found to increase and then to decrease, with the
maximum height occurring at an angle of inclination of about 10°. This behaviour is
due a combination of the decreased interaction between the upflow and the downflow,
and the decreased vertical momentum of the injected fluid, as the angle of inclination
is increased.
A new model for shallow water in the
low-Rossby-number limit
Authors: FORD RUPERT , MALHAM SIMON J. A. , OLIVER MARCEL
Published: August 2008

We revisit Salmon's ‘Dirac bracket projection’ approach to constructing generalized
semi-geostrophic equations. One of the obstacles to the method's applicability is
that it leads to a sign-indefinite energy functional in the computational domain.
In some instances this can cause severe failure of the model. We demonstrate in
the simple context of shallow-water semi-geostrophy that the Hamiltonian remains
positive definite when the asymptotic expansion at the heart of this method is carried
to the next order. The resulting new model can be interpreted in the framework of
regularization by Lagrangian averaging, which is currently receiving much attention.
Force on a body in a continuously
stratified fluid. Part 1. Circular cylinder
Authors: ERMANYUK EUGENY V. , GAVRILOV NIKOLAI V.
Published: August 2008

This paper presents the force coefficients (added mass and damping) for a circular
cylinder oscillating horizontally in a uniformly stratified fluid of limited depth and
in a continuously stratified fluid with a smooth pycnocline. The frequency-dependent
added mass and damping are evaluated from Fourier transforms of the experimental
records of impulse response functions. The stratification is shown to have a strong
effect on the fluid–body interaction. It is found that, when the characteristic vertical
extent of stratification (depth of uniformly stratified fluid or pycnocline thickness)
decreases, the power radiated with internal waves is reduced and the maximum of
the frequency spectrum of wave power shifts toward lower frequency. The results of
experiments are compared with available theoretical predictions.
The turbulent/non-turbulent interface bounding a far wake
Authors: BISSET DAVID K. , HUNT JULIAN C. R. , ROGERS MICHAEL M.
Published: August 2008

The velocity fields of a turbulent wake behind a flat plate obtained from the direct
numerical simulations of Moser et al. (1998) are used to study the structure of the
flow in the intermittent zone where there are, alternately, regions of fully turbulent
flow and non-turbulent velocity fluctuations on either side of a thin randomly moving
interface. Comparisons are made with a wake that is ‘forced’ by amplifying initial
velocity fluctuations. A temperature field T, with constant values of 1.0 and 0 above
and below the wake, is transported across the wake as a passive scalar. The value of
the Reynolds number based on the centreplane mean velocity defect and half-width
b of the wake is Re ≈ 2000.

The thickness of the continuous interface is about 0.07b, whereas the amplitude of
fluctuations of the instantaneous interface displacement yI(t) is an order of magnitude
larger, being about 0.5b. This explains why the mean statistics of vorticity in the
intermittent zone can be calculated in terms of the probability distribution of yI
and the instantaneous discontinuity in vorticity across the interface. When plotted as
functions of y−yI the conditional mean velocity 〈U〉 and temperature 〈T〉 profiles
show sharp jumps at the interface adjacent to a thick zone where 〈U〉 and 〈T〉 vary
much more slowly.

Statistics for the conditional vorticity and velocity variances, available in such detail
only from DNS data, show how streamwise and spanwise components of vorticity are
generated by vortex stretching in the bulges of the interface. While mean Reynolds
stresses (in the fixed reference frame) decrease gradually in the intermittent zone,
conditional stresses are roughly constant and then decrease sharply towards zero
at the interface. Flow fields around the interface, analysed in terms of the local
streamline pattern, confirm and explain previous results that the advancement of the
vortical interface into the irrotational flow is driven by large-scale eddy motion.

Terms used in one-point turbulence models are evaluated both conventionally and
conditionally in the interface region, and the current practice in statistical models of
approximating entrainment by a diffusion process is assessed.
Low-dimensional modelling of a transient cylinder wake using double proper orthogonal decomposition
Authors: SIEGEL STEFAN G. , SEIDEL JÜRGEN , FAGLEY CASEY , LUCHTENBURG D. M. , COHEN KELLY , MCLAUGHLIN THOMAS
Published: August 2008

For the systematic development of feedback flow controllers, a numerical model that captures the dynamic behaviour of the flow field to be controlled is required. This poses a particular challenge for flow fields where the dynamic behaviour is nonlinear, and the governing equations cannot easily be solved in closed form. This has led to many versions of low-dimensional modelling techniques, which we extend in this work to represent better the impact of actuation on the flow. For the benchmark problem of a circular cylinder wake in the laminar regime, we introduce a novel extension to the proper orthogonal decomposition (POD) procedure that facilitates mode construction from transient data sets. We demonstrate the performance of this new decomposition by applying it to a data set from the development of the limit cycle oscillation of a circular cylinder wake simulation as well as an ensemble of transient forced simulation results. The modes obtained from this decomposition, which we refer to as the double POD (DPOD) method, correctly track the changes of the spatial modes both during the evolution of the limit cycle and when forcing is applied by transverse translation of the cylinder. The mode amplitudes, which are obtained by projecting the original data sets onto the truncated DPOD modes, can be used to construct a dynamic mathematical model of the wake that accurately predicts the wake flow dynamics within the lock-in region at low forcing amplitudes. This low-dimensional model, derived using nonlinear artificial neural network based system identification methods, is robust and accurate and can be used to simulate the dynamic behaviour of the wake flow. We demonstrate this ability not just for unforced and open-loop forced data, but also for a feedback-controlled simulation that leads to a 90% reduction in lift fluctuations. This indicates the possibility of constructing accurate dynamic low-dimensional models for feedback control by using unforced and transient forced data only.
Beating of a circular cylinder mounted as an inverted pendulum
Authors: VOORHEES A. , DONG P. , ATSAVAPRANEE P. , BENAROYA H. , WEI T.
Published: August 2008

This paper contains temporally and spatially resolved flow visualization and DPIV measurements characterizing the frequency–amplitude response and three-dimensional vortex structure of a circular cylinder mounted like an inverted pendulum. Two circular cylinders were examined in this investigation. Both were 2.54 cm in diameter and ~140 cm long with low mass ratios, m* = 0.65 and 1.90, and mass–damping ratios, m*ζ = 0.038 and 0.103, respectively. Frequency–amplitude response analysis was done with the lighter cylinder while detailed wake structure visualization and measurements were done using the slightly higher-mass-ratio cylinder. Experiments were conducted over the Reynolds number range 1900≤Re≤6800 corresponding to a reduced velocity range of 3.7 ≤ U* ≤ 9.6. Detailed examination of the upper branch of the synchronization regime permitted, for the first time, the identification of short-time deviations in cylinder oscillation and vortex-shedding frequencies that give rise to beating behaviour. That is, while long-time averages of cylinder oscillation and vortex-shedding frequencies are identical, i.e. synchronized, it is shown that there is a slight mismatch between these frequencies over much shorter periods when the cylinder exhibits quasi-periodic beating. Data are also presented which show that vortex strength is also modulated from one cylinder oscillation to the next. Physical arguments are presented to explain both the origins of beating as well as why the quasi-periodicity of the beating envelopes becomes irregular; it is believed that this result may be generalized to a broader class of fluid–structure interactions. In addition, observations of strong vertical flows associated with the Kármán vortices developing 2–3 diameters downstream of the cylinder are presented. It is hypothesized that these three-dimensionalities result from both the inverted pendulum motion as well as free-surface effects.
The effects of flow stratification by non-cohesive sediment on transport in high-energy wave-driven flows
Authors: CONLEY DANIEL C. , FALCHETTI SILVIA , LOHMANN IRIS P. , BROCCHINI MAURIZIO
Published: August 2008

The two-way effects of the time-varying suppression of turbulence by gradients in suspended sediment concentration have been investigated using a modified form of the Generalized Ocean Turbulence Model (GOTM). Field measurements of fluid velocities and sediment concentrations collected under high-energy conditions (mobility number ≈ 900) have been simulated both including and neglecting the feedback between sediment and turbulence. The results show that, when present, this feedback increases the wave-coherent component of transport relative to the mean component of transport, which can even change the direction of transport. Comparisons between measured and simulated time series of near-bed sediment concentrations show great coherence (0.95 correlation) and it is argued that the differences in net transport rates may be partially explained by the use of a uniform grain size in the simulations. It is seen that the effects of sediment stratification scale with orbital velocity divided by sediment setting velocity,um/ws, for all grain sizes.
Linear instability of annular Poiseuille flow
Authors: HEATON C. J.
Published: August 2008

The linear stability of flow along an annular pipe formed by two coaxial circular cylinders is considered. We find that the flow is unstable above a critical Reynolds number for all 0 < η ≤ 1, where η is the ratio between the radii of the inner and outer cylinders. This contradicts a recent claim that the flow is stable at all Reynolds numbers for radius ratio η less than a finite critical value. We find that non-axisymmetric disturbances become stable at all Reynolds numbers for η < 0.11686215, and we are able to study this ‘bifurcation from infinity’ asymptotically. However, axisymmetric disturbances remain unstable, with critical Reynolds number tending to infinity as η → 0. A second asymptotic analysis is performed to show that the critical Reynolds number Rec ∝ η−1 log(η−1) as η → 0, with the form of the mean flow profile causing the appearance of the logarithm. The stability of Hagen–Poiseuille flow (η = 0) at all Reynolds numbers is therefore interpreted as a limit result, and there are no annular pipe flows which share this stability.
Field-induced motion of ferrofluid droplets through immiscible viscous media
Authors: AFKHAMI S. , RENARDY Y. , RENARDY M. , RIFFLE J. S. , St PIERRE T.
Published: August 2008

The motion of a hydrophobic ferrofluid droplet placed in a viscous medium and driven by an externally applied magnetic field is investigated numerically in an axisymmetric geometry. Initially, the drop is spherical and placed at a distance away from the magnet. The governing equations are the Maxwell equations for a non-conducting flow, momentum equation and incompressibility. A numerical algorithm is derived to model the interface between a magnetized fluid and a non-magnetic fluid via a volume-of-fluid framework. A continuum-surface-force formulation is used to model the interfacial tension force as a body force, and the placement of the liquids is tracked by a volume fraction function. Three cases are studied. First, where inertia is dominant, the magnetic Laplace number is varied while the Laplace number is fixed. Secondly, where inertial effects are negligible, the Laplace number is varied while the magnetic Laplace number is fixed. In the third case, the magnetic Bond number and inertial effects are both small, and the magnetic force is of the order of the viscous drag force. The time taken by the droplet to travel through the medium and the deformations in the drop are investigated and compared with a previous experimental study and accompanying simpler model. The transit times are found to compare more favourably than with the simpler model.
Constrained flow around a magnetic obstacle
Authors: VOTYAKOV EVGENY V. , ZIENICKE EGBERT , KOLESNIKOV YURI B.
Published: August 2008

Many practical applications exploit an external local magnetic field – magnetic obstacle – as an essential part of their operation. It has been demonstrated that the flow of an electrically conducting fluid influenced by an external field can show several kinds of recirculation. The present paper reports a three-dimensional numerical study, some results of which are compared with an experiment on such a flow in a rectangular duct. First, we derive equations to compute analytically the external magnetic field and verify these equations by comparing with experimentally measured field intensity. Then, we study flow characteristics for different magnetic field configurations. The flow inside the magnetic gap is dependent mainly on the interaction parameter N, which represents the ratio of the Lorentz force to the inertial force. Depending on the constrainment factor κ = My/Ly, where My and Ly are the half-widths of the external magnet and duct, the flow can show different stationary recirculation patterns: two magnetic vortices at small κ, a six-vortex ensemble at moderate κ, and no vortices at large κ. Recirculation appears when N is higher than a critical value Nc,m. The driving force for the recirculation is the reverse electromotive force that arises to balance the reverse electrostatic field. The reversal of the electrostatic field is caused by the concurrence of internal and external vorticity respectively related to the internal and external slopes in the M-shaped velocity profile. The critical value of Nc,m grows quickly as κ increases. For the case of well-developed recirculation, the numerical reverse velocity agrees well with that obtained in experiments. Two different magnetic systems can induce the same electric field and stagnation region provided these systems have the same power of recirculation, given by the N/Nc,m ratio. The three-dimensional helical characteristics of the vortices are elaborated, and an analogy is shown to exist between helical motion inside the recirculation studied and secondary motion in Ekman pumping. Finally, it is shown that a two-dimensional model fails to properly produce stable two- and six-vortex structures as found in the three-dimensional system. Interestingly, these recirculation patterns appear only as time-dependent and unstable transitional states before a Kármán vortex street forms, when one suddenly applies a retarding local magnetic field to a constant flow.
Long-range interaction and elastic collisions of isolated vortices
Authors: RADKO TIMOUR
Published: August 2008

This study explores the interaction of two nearly axisymmetric two-dimensional vortices using a combination of numerical simulations and analytical arguments. We consider isolated or ‘shielded’ eddies, characterized by zero net vorticity. The ability of such vortices to propagate and interact is associated with the small dipolar component that is introduced initially. Numerical contour dynamics experiments indicate that the interaction of shielded eddies takes one of two forms, depending on their initial separation and on the relative orientation of their dipolar components. Eddies can influence each other by remotely modifying the dipolar moments of partner vortices, an effect manifested in a gentle deflection of their trajectories from a straight course. Strong interactions occur when eddies collide and rebound. The remote interaction is explained by weakly nonlinear theory in which the basic state consists of identical circularly symmetric eddies and the perturbation is assumed to be small. It is argued that the elastic rebounds observed during direct collisions are induced by the exchange of fluid between colliding vortices.
Bending of floating flexible legs
Authors: PARK KUN JOONG , KIM HO-YOUNG
Published: August 2008

When long thin flexible solid objects, such as the legs of water striders, disposable spoons and human hairs, are pressed against a liquid surface, they bend due to interfacial and hydrostatic forces. To understand the phenomenon, we study the bending of a sheet touching the liquid surface at an angle while clamped at the other end, to find its deflection and the load that the sheet can support before sinking. The theoretically predicted shapes of the sheet and the meniscus match well with experiments. Our theory shows that flexible sheets can support more load than rigid ones before sinking when the sheets are highly hydrophobic.
A new species ofSyllis(Polychaeta: Syllidae: Syllinae) from off Fortaleza, north-eastern Brazil
Authors: de Matos Nogueira João Miguel , Yunda-Guarin Gustavo
Published: August 2008

In a study investigating the composition and spatial and temporal variation of the benthic macrofauna associated to the discharge of domestic sewage off Fortaleza, north-eastern Brazil, a new species ofSylliswas found. This new species,S. guidaesp. nov., is characterized by having blades of falcigers with subdistal tooth about same length as distal tooth, but stouter than it, with spines on cutting edge almost reaching the tip of subdistal tooth, blades of falcigers with conspicuous subdistal triangular process and unusually long anal papilla between anal cirri, measuring about one-quarter of their length.Syllis guidaesp. nov., is herein described and compared with the most similar congeners.
Two new species of flatworms (Platyhelminthes: Polycladida) from the continental slope of the Gulf of Mexico
Authors: Quiroga Sigmer Y. , Bolaños D. Marcela , Litvaitis Marian K.
Published: August 2008

Two new species of polyclads are described from the continental slope of the Gulf of Mexico. Specimens ofDidangia carneyisp. nov. andOligocladus bathymodiensissp. nov. were collected from the Louisiana slope at 610 m and 650 m, respectively.Didangia carneyisp. nov. was collected from a natural wood fall, and is characterized by the presence of tentacular and cerebral eyes, an interpolated prostatic vesicle provided with two muscular accessory prostatic vesicles, and large glandular cells that surround the male atrium.Oligocladus bathymodiensissp. nov. has a mouth anterior to the brain, a few cerebral and pseudotentacular eyes, four pairs of intestinal branches, and a ventral anal pore. Specimens of this species were collected on the margin of a hypersaline cold seep in association with mussels ofBathymodiolus childressi. All type material is deposited at the Field Museum of Natural History, Chicago, Illinois, USA.
Child obesity: what can be done and who will do it?
Authors: Lobstein Tim
Published: August 2008

Among the measures recommended by the WHO to reduce the risk of obesity and non-communicable disease, the consumption of a diet rich in micronutrients but with a relatively-low energy density features prominently. However, only a small percentage of the UK population (<1) appears to be consuming the recommended diet. Dietary behaviour is strongly influenced by the dietary environment, shaped by food supplies, investment policies and advertising, to create an obesogenic food market. Substantial resources have been invested in food production of a sort that does not promote better health; agriculture and food supply sectors have benefited from decades of public-sector support, but this practice has encouraged the production of meat, dairy, oils and sugar and the withdrawal from sale of fruit, vegetables and fish. The result is an ‘obesogenic economy’, i.e. a market economy that encourages weight gain, in which children are a prime target. Interventions in the obesogenic market need to be considered and several opportunities are described in the present paper. Recent moves to strengthen national and international food policies aimed to promote healthier behaviour have been undertaken, but they will need political support if they are to be fully implemented. Alliances of public health interests can help to create that political support and promote health-enhancing environments.
NUMBER ONE HUNDRED AND EIGHTEEN August to October 2000
Authors: BENNETT FRAN
Published: August 2008

Contents

1 Social security and income maintenance

2 Health (formerly Health care)

3 Education

4 Housing and environment

5 Personal social services

6 Law and the treatment of the offender

7 Unemployment and the labour market

8 Race relations

9 The voluntary sector

10 Government (formerly Local government)

11 Gender

12 Demography
Paul V. Dutton,Origins of the French Welfare State: The Struggle for Social Reform in France, 1914–1947. Cambridge: Cambridge University Press, 2002. xiii + 251 pp. $65.00 cloth; $27.00 paper.
Authors: Chapman Herrick
Published: August 2008

Comparative studies of social policy usually portray the French welfare state as lagging behind most of its counterparts in Western Europe during the first decades of the twentieth century. The sheer complexity of the French system, moreover, with its baroque mixture of separate private, government and quasi-public funds, made it exceptional as well. Yet tardiness and complexity by no means prevented the French from expanding social insurance at an especially rapid clip in the decades following the Second World War. By 1980 France spent more on social security as a percentage of Gross Domestic Product than any country in Europe except Denmark, Sweden and the Netherlands. Today the French are among Europe's most stalwart defenders of publicly funded pensions and health insurance. Given its unimpressive beginnings, how did the French welfare state become such a heavyweight?
J.K. Gibson-Graham, Stephen Resnick, and Richard D. Wolff,Re/presenting Class: Essays in Post-Modern Marxism. London: Duke University Press, 2001. 336 pp. $54.95 cloth; $18.95 paper.
Authors: Plaw Avery
Published: August 2008

Re/Presenting Class is a timely and evocative collection of essays devoted to exploring the contribution postmodern Marxist class theory can make to the contemporary study of political economy. This multifaceted exploration marks a refreshing departure from the conventional focus of the political economic tradition on classical Marxist analysis of the capitalist system as a total system or mode of production. On this conventional approach, class functions merely as an instrument of the dominant mode of capital accumulation. By contrast, the essays in Gibson-Graham, Resnick and Wolff's collection employ various forms of class analysis as an independent means to illuminate contemporary and historical political economies. Here class is understood not simply as an instrumentality of capitalist accumulation, but as a set of independent “processes of producing, appropriating and distributing surplus labor” (17, 169). In essence, the essays attempt, in various ways, to extricate class analysis from general “theory of the capitalist totality,” (1) and to examine what kinds of insight it can offer as an independent framework in its own right. In general, the project repays the investment just as the book rewards reading.
Priscilla Murolo and A.B. Chitty; illustrations by Joe Sacco,From the Folks Who Brought You the Weekend: A Short Illustrated History of Labor in the United States. New York: The New Press, 2001. xx + 364 pp. $27.50 cloth; $17.95 paper.
Authors: Le Blanc Paul
Published: August 2008

The title of this book, cutely folksy, may help to attract some readers who would be intimidated or put off by something more accurate (captured in the subtitle), but it obscures the achievement of this splendid contribution by Priscilla Murolo and A.B. Chitty.
Nano-structured lithium-tin plane fabrication for laser produced plasma and extreme ultraviolet generation
Authors: Nagai Keiji , Gu Q. , Norimatsu T. , Fujioka S. , Nishimura H. , Miyanaga N. , Nishihara K. , Izawa Y. , Mima K.
Published: August 2008

This paper deals with a lithium/tin combined target to increase the conversion efficiency of extreme ultraviolet (EUV) of 13.5 nm emission from laser-produced plasma. The bilayer target of glass/lithium (20 nm)/tin (50 nm) exhibits a sharp and strong emission in comparison with a Sn bulk target. The reverse coating of glass/tin/lithium was unstable and EUV could not be observed. By using nano-porous SnO2 and an electrochemical deposition of lithium, nano-structured lithium/tin composite was prepared, and was stable without deliquescence of lithium.
Cantonese particles in Hong Kong students' English e-mails
Authors: James Gregory
Published: August 2008

With the popularisation of the Internet, the use of e-mails and computer-based chats (CBCs) has increased dramatically among university students. An interesting feature of such communication, however, is that a written medium is treated like speech (cf. Maynor, 1994).
Conversations turn into notes where grammatical accuracy and conventional formalities take a backseat to instant communication. In the case of on-campus CBCs, informality and a certain disregard of the conventions of standard English are all the more manifest.

It is commonly believed in Hong Kong that this general freedom to write ‘bad English’ has encouraged the habit of randomly incorporating Cantonese words into English e-mails. Yet an examination of students' e-mails and icq (‘I Seek You’) communications reveals that far from ‘polluting’ their English by substituting Cantonese words haphazardly for English ones, or by applying Cantonese structures to their English writing, students tend to incorporate certain kinds of Cantonese words systematically into their texts for specific identifiable purposes.
Digital age, digital English
Authors: Liwei Gao
Published: August 2008

A response to the articles on e-mail by Li Lan and Li Yongyan in ET64 (Oct 00). This article discusses what has been happening to e-mail English and what might yet happen as a consequence to off-line English. The paper first examines the effect on the use of English in the electronic medium. It then talks about the influence of e-mail English on the off-line use of English, and closes with a description of the interface between English and Chinese in e-mails.

Li Yongyan focuses on the discursive aspect of e-mail messages in her article. She mainly talks about styles and coherence in e-mail writing. In contrast, Li Lan primarily describes the linguistic aspect of e-mail English. Her article discusses both the conversational style of, and innovations and distinctive usages in, e-mail English. Both also describe English-Chinese code-mixing in their articles, as well as the emergence of novel linguistic features in e-mail English, such as the omission of the sentence subject.
Road construction in the Peruvian Amazon: process, causes and consequences
Authors: Mäki Sanna , Kalliola Risto , Vuorinen Kai
Published: August 2008

In the north-western Peruvian Amazon, a new road has recently been constructed to link the city of Iquitos with the town of Nauta. The road crosses lands that are remarkably heterogeneous in terms of ecological conditions, comprising distinctive soil types from extremely poor to relatively fertile. Although this reality contributes to the land use potential and human carrying capacity of each place, deforestation of road margins appears equally intensive on all types of land. In the mid-1990s, two dead-end roads starting from both urban centres were characterized by distinctive zones of resource exploitation, with a road-free section of primary forest in between. A few years later, the separate road ends were linked by a dirt road that served only occasional traffic, but introduced significant new settlement. Various developmental trends evidence incoherent resource management and momentary public support in the region. By promoting diverse economic activities that reflect environmental conditions in the initial land use planning and land allocation, most sections along this road could be considered economically valuable for purposes such as sustainable forestry, tourism, agroforestry and, in suitable sites, intensive agriculture. To promote the more sustainable uses, thorough environmental legislation, administrative guidelines and follow-up based on an implicit mechanism of learning from previous experiences should be implemented. At the local level, there are some important initiatives to support such development, including ecological and economic zoning. However, these measures might be too late to prevent the destructive practices so common in many parts of Amazonia.
The non-extractive economic value of spiny lobster, Panulirus argus, in the Turks and Caicos Islands
Authors: Rudd Murray A.
Published: August 2008

Increases in spiny lobster size and abundance have been observed within some marine protected areas (MPAs). To date, the potential economic benefits of these changes have been assumed to derive from the effects of emigration of adult lobster to adjacent fishing grounds and/or increased larval export to downstream nurseries that sustain fisheries. According to economic theory, these effects may provide consumptive (extractive) economic value to the fishery but are only part of the total economic value. Non-extractive economic value resulting from viewing wildlife may also have an important impact on the overall economic viability of some MPAs. This research examined scuba diver preferences in the Turks and Caicos Islands using a paired comparison conjoint survey and assessed the influence that spiny lobster (Panulirus argus) presence had on market share for dive charter packages of varying environmental quality and price. Market simulations showed significant increases in market share for dives where spiny lobsters were present, implying, for the first time, that spiny lobsters have non-extractive economic value. This non-extractive value of spiny lobster may have an important impact on the economic viability of some MPAs, especially those in regions like the Turks and Caicos Islands that are highly dependent on marine-oriented nature tourism.
Monitoring changes in feral swine abundance and spatial distribution
Authors: Engeman Richard M. , Constantin Bernice , Nelson Mark , Woolard John , Bourassa Jean
Published: August 2008

Swine (Sus scrofa) have been introduced in many places throughout the world, and in many places they adversely affect the environment, economically impact agriculture, and/or harbour diseases transmittable to domestic livestock or humans. An easily applied method to assess their abundance is an important need for their management. To monitor efficacy of a swine control programme in Florida, data from passive tracking plots provide an index of feral swine abundance. The same track data coupled with plot locations to numerically describe the spatial pattern of swine activity gave an index of pervasiveness, and a simple rate of interception of damage sites to index damage was used. The assessments were conducted in January, May, and August 2000 in Jonathan Dickinson State Park, Florida, USA. Between the first two assessments a swine control programme removed 25 feral swine from the 8.3 km2 study area, after which the value of the passive tracking index was reduced by 81% and the fresh damage index by 89%, while the index of spatial pattern (pervasiveness index) showed only a small localized concentration after control. In the three months following the second assessment, Park personnel removed three additional swine from the study area, and a follow-up assessment indicated slightly less swine activity than immediately after the post-control assessment, however the index of pervasiveness showed a similar spatial pattern of activity as the initial assessment, possibly indicating re-invasive pressure. The passive tracking plots proved to be an uncomplicated, easily applied means to gather data for assessing and comparing swine abundance and distribution.
Alert distance as an alternative measure of bird tolerance to human disturbance: implications for park design
Authors: Fernández-Juricic Esteban , Jimenez María Dolores , Lucas Elena
Published: August 2008

Animal tolerance to human approaches may be used to establish buffers for wildlife that can minimize the probability that animals will be disturbed by human activity. Alert distance (the distance between an animal and an approaching human at which point the animal begins to exhibit alert behaviours to the human) has been proposed as an indicator of tolerance mainly for waterbirds; however, little is known about its utility for other bird species. The factors that influenced alert distances of four bird species to pedestrian approaches in five large wooded fragments in the city of Madrid (Spain) were analysed. Location of human activity affected only Passer domesticus alert distances, which increased in the proximity of pathways. Habitat structure modified alert distances of all the species (Passer domesticus, Turdus merula, Columba palumbus, and Pica pica), increasing bird tolerance with greater availability of escape cover (shrub and coniferous cover, and shrub height). Alert distances varied among species, with large species being less tolerant of human disturbance than small ones. Alert distance appears to be a more conservative indicator of tolerance than flight distances, because it includes a buffer zone (the difference between alert and flight distance) in which birds may adapt their reaction to the behaviour of visitors. Alert distance may be used in the determination of minimum approaching areas, allowing people to enjoy their visit to parks, and birds to use patches for foraging and breeding without being displaced.
Selection bias in epidemiological studies of infectious disease using Escherichia coli and avian cellulitis as an example
Authors: SINGER R. S. , ATWILL E. R. , CARPENTER T. E. , JEFFREY J. S. , JOHNSON W. O. , HIRSH D. C.
Published: August 2008

In epidemiological studies of infectious disease, researchers often rely on specific cues of the host, such as clinical signs, as surrogate indicators of pathogen presence. A selection bias would manifest if the specific visual cues used in sampling for the pathogen were not representative of the full range of signs caused by the strains of that pathogen. In our molecular epidemiological studies of Escherichia coli associated with avian cellulitis in broilers, we collect carcasses at the processing plant based on visual cues of lesion morphology. Therefore, the objectives of this study were to: (1) explore the potential impacts of selection bias in an application of infectious disease epidemiology, and (2) utilize a validation protocol to assess the potential for selection bias in our molecular epidemiological studies of E. coli and avian cellulitis. In two different trials, E. coli DNA fingerprints were compared between birds that our observers collected and the birds that the observers missed. Using Fisher's exact tests and simulation models, we determined that the isolates collected by the observers were not significantly different from the isolates missed by the observers (P>0·60 in both trials). Our method of selecting birds suspected of having cellulitis did not significantly bias our inferences about the population of E. coli associated with cellulitis in the flock. We encourage more investigators to critically assess the relationship of the sample to the target population in epidemiological studies of infectious disease.
Prevalence of antibodies to hepatitis C virus, HIV and human T-cell leukaemia/lymphoma viruses in injecting drug users in Tayside, Scotland, 1993–7
Authors: MCINTYRE P. G. , HILL D. A. , APPLEYARD K. , TAYLOR A. , HUTCHINSON S. , GOLDBERG D. J.
Published: August 2008

The prevalence of blood-borne viruses in injecting drug users (IDUs) in Tayside, Scotland was determined by testing serum samples from IDUs who underwent attributable HIV antibody testing during 1993–7. The prevalence of antibodies to HIV was 29/802, (3·6%); to hepatitis C virus (HCV) 451/691, (65·3%); and to human T-cell leukaemia/lymphoma viruses type 1 and 2 (HTLV) 0/679, (0·0%). The prevalence of HIV and HCV antibodies were higher in subjects over the age of 25 (P=0·03 and P=0·001, respectively). During 1993–7 the prevalence of HCV fell only in younger female IDUs (P<0·01). HIV prevalence has declined dramatically since 1985, when a rate of 40% was recorded in similar populations. Harm reduction measures have failed to control HCV the spread of infection among IDUs in Tayside, as indicated by the high proportion of antibody positive IDUs, particularly males under the age of 25. Future studies should address the nature and effective reduction of continuing risk taking among IDUs in Tayside.
Death rates and causes of death in cohorts of serum hepatitis patients followed up for more than 20 years
Authors: GJERULDSEN S. , ABDELNOOR M. , OPJORDSMOEN S. , MYRVANG B.
Published: August 2008

A cohort of 214 drug addicts with serum hepatitis and a cohort of 193 hepatitis patients without drug addiction were examined in respect of death rates, causes of death and a number of risk factors for reduced survival. The death rate was significantly higher among the drug addicts than among non-addicts. The annual mortality rate was 1·5% in the drug addict group and 0·7% in the non-addict group. The highest relative risk of death was 860 for female drug addicts in age group 15–24 compared to females of the same age in the general population. The most prevalent cause of death in the drug addict group was drug overdose (53%), whereas in the other group 66% died from various somatic diseases. Hepatitis or complications of viral hepatitis played no role as cause of death among the drug addicts, and infections as a whole were also responsible for very few deaths. For male drug addicts, imprisonment before admission and leaving hospital without the doctors' permission were risk factors for early death.
Excess hospital admissions for pneumonia and influenza in persons [ges ]65 years associated with influenza epidemics in three English health districts: 1987–95
Authors: NGUYEN-VAN-TAM J. S. , BROCKWAY C. R. , PEARSON J. C. G. , HAYWARD A. C. , FLEMING D. M.
Published: August 2008

Objectives: To study the association between community influenza activity and acute hospital admissions for pneumonia and influenza among elderly persons.

Design: Multiple regression analysis of acute hospital admissions against community influenza activity, air temperature and seasonal and long-term trends.

Setting: Three English health districts: 1987–95.

Subjects: Persons aged [ges ]65 years.

Outcome measures: Acute hospital admissions for pneumonia and influenza (ICD9: 480–487); excess hospital admissions during epidemic periods.

Results: The final regression model explained 70% of the total variation in hospital admissions for pneumonia and influenza, including 14% due to community influenza activity. However, most variation was explained by long-term and seasonal changes unrelated to influenza. In the large influenza epidemic of 1989/90 a typical health district (500000 total population) experienced 56 excess admissions for pneumonia and influenza attributable to epidemic influenza among persons aged [ges ]65 years, requiring 672 additional bed-days. However the figure varied widely between seasons and over the whole study period, the average winter excess was 17·5 admissions per health district, requiring an additional 210 bed-days.

Conclusions: Influenza epidemics exert a variable impact on acute hospital admissions for pneumonia and influenza among elderly persons, which in the past have been poorly quantified. Although the absolute numbers of excess admissions is modest, their impact on bed availability may be considerable because of the duration of hospital stay in elderly persons.
Molecular epidemiology of multiple drug resistant type 6B Streptococcus pneumoniae in the Northern Territory and Queensland, Australia
Authors: CARLISLE J. B. , GRATTEN M. , LEACH A. J.
Published: August 2008

The emergence of type 6B Streptococcus pneumoniae resistant to five antibiotics (penicillin, chloramphenicol, trimethoprim–sulphamethoxazole, erythromycin and tetracycline) in both the Northern Territory and Queensland prompted an investigation of the genetic relatedness and patterns of migration of the isolates. Pulsed field gel electrophoresis of genomic DNA of 74 multiple drug-resistant (MDR) isolates cultured in both regions between August 1988 and June 1997 showed that 100% of MDR isolates from the Northern Territory and 96% of MDR strains from Queensland were genetically indistinguishable or closely related to the index strain. None of a further 65 type 6B isolates that were resistant to one or two, or susceptible to all of the above antibiotics, were clonally related to the MDR pneumococci. The geographical distribution of the MDR type 6B clone increased over time. The index strain, first isolated in Darwin in August 1988, was identified in Brisbane, 2900km distant, less than 4 years later and subsequently in other Queensland centres. Surveillance programmes are important to monitor the emergence and spread of potentially invasive MDR pneumococcal clones in countries that are well serviced by air and road transport.