bluuebunny/crossref_metadata_2025 huggingface dataset:
Streamwise absolute instability of a
three-dimensional boundary layer at high
Reynolds numbers
Authors: RYZHOV OLEG S. , TERENT'EV EUGENE D.
Published: July 2002

The simplest receptivity problem of linear disturbances artificially
excited in a
three-dimensional boundary layer adjacent to a solid surface is studied
in the framework
of the generalized triple-deck theory. In order to provide a mathematical
model to
be compared with experimental data from wind-tunnel tests we consider the
base
flow over a swept flat plate. Then crossflow in the near-wall region originates
owing
to an almost constant pressure gradient induced from outside with a displacement

body on top. A pulsed or vibrating ribbon installed on the solid surface
serves as
an external agency provoking initially weak pulsations. A periodic dependence
of
the ribbon shape on a coordinate normal to the streamwise direction makes
the
receptivity problem effectively two-dimensional, thereby allowing a rigorous
analysis
to be carried out without additional assumptions.

The most striking result from the asymptotic theory is the discovery
of streamwise
absolute instability intrinsic to a three-dimensional boundary layer at
high Reynolds
numbers. However, due to limitations imposed on the receptivity problem
no definite
conclusions can be made with regard to possible continued convection of
disturbances
in the crossflow direction. An investigation of the dispersion-relation
roots points to
the fact that wave packets of different kinds can be generated by an external
source
operating in the pulse mode. Rapidly growing wave packets sweep downstream,

weaker wave packets move against the oncoming stream. Insofar as the amplitude
of
all of the modulated signals increases exponentially in time and space,
the excitation
process gives rise to absolutely unstable disturbances in the streamwise
direction.
The computation confirms the theoretical prediction about the existence
of
upstream-advancing wave packets. They can be prevented from being persistently
amplified
only in a region ahead of the ribbon where nearly critical values of the
Reynolds
number are attained.

The results achieved are shown to be broadly consistent with wind-tunnel
measurements.
Hence a conjecture is made that the onset of transition is probably associated,

under some environmental conditions, with the mechanism of streamwise absolute

instability in the supercritical range of the Reynolds numbers.
A note on tuning in Roseau's alternative edge waves
Authors: EHRENMARK ULF TORSTEN
Published: July 2002

Ursell's edge waves are derived systematically using
a new method. Computed profiles
are then compared with the lesser known shoreline singular waves first
constructed by
Roseau (1958). A recent method of writing the continuous spectrum solutions
on a
plane beach is thereby extended to the discrete spectrum to enable the
reconstruction
of both types of edge waves so that, in particular, the unbounded wave
profiles are
more easily computed. The existence of stagnation points on the bed for
standing
edge waves is considered and demonstrated for the first few modes. A ramification

of this is the existence of (two-dimensional-cross-shore)
dividing ‘streamlines’ from
the bed to the surface also, the number of which appears to equate to the
modal
number of the edge wave. These dividing streamlines, along with other streamlines,

are computed for the first few modes of both the Ursell and the (alternative)
singular
waves constructed by Roseau.

It follows that these waves can also exist in the presence of solid
cylinders bounded
by fixed streamlines and, in particular therefore, that the hitherto unbounded
Roseau
waves can exist in a bounded state since a region including the origin
can be removed
from the flow by exploiting a dividing streamline. It is confirmed that
the wavenumbers
of the Roseau waves interlace those of the Ursell waves. An examination
of available
evidence leaves open to further research the question of whether the alternative

Roseau waves have been ‘inadvertently’ observed either in the
laboratory or, by
means of contamination of data, in the field. Further laboratory simulations
using
longshore solid cylinders as ‘wave guides’ are proposed.
The anomalous motion of superfluid helium in a rotating cavity
Authors: HENDERSON KAREN L. , BARENGHI CARLO F.
Published: July 2002

We numerically solve the nonlinear two-fluid Hall–Vinen–Bekharevich–Khalatnikov
(HVBK) equations for superfluid helium confined inside a short Couette annulus. The
outer cylinder and the ends of the annulus are held fixed whilst the inner cylinder
is rotated. This simple flow configuration allows us to study how the vortex lines
respond to a shear in the presence of boundaries. It also allows us to investigate
further the boundary conditions associated with the HVBK model. The main result
of our investigation is the anomalous motion of helium II when compared to a
classical fluid. The superfluid Ekman cells always rotate in the opposite sense to a
classical Navier–Stokes fluid due to the mutual friction between the two fluids, whilst
the sense of rotation of the normal fluid Ekman cells depends on the parameter range
considered. We also find that the tension of the vortex lines forces the superfluid to
rotate about the inner cylinder almost like a rigid column.
Negation, ‘presupposition’
and metarepresentation: a response
to Noel Burton-Roberts
Authors: CARSTON ROBYN
Published: July 2002

Metalinguistic negation (MN) is interesting for at least the following two
reasons: (a) it is one instance of the much broader, very widespread and
various phenomenon of metarepresentational use in linguistic communication,
whose semantic and pragmatic properties are currently being
extensively explored by both linguists and philosophers of language; (b) it
plays a central role in recent accounts of presupposition-denial cases, such as
‘The king of France is not bald; there is no king of France’. It is this latter
employment that discussion of metalinguistic negation has focused on since
Horn (1985)'s key article on the subject. While Burton-Roberts (1989a,
1989b) saw the MN account of presupposition-denials as providing strong
support for his semantic theory of presupposition, I have offered a multi-layered pragmatic account of these cases, which also involves MN, but
maintains the view that the phenomenon of presupposition is pragmatic
(Carston 1994, 1996, 1998a).
Eigenmode scattering theorems for electromagnetic–acoustic fields
in
compressible magnetoplasmas with anisotropic pressure
Authors: SUCHY K. , ALTMAN C.
Published: July 2002

The electromagnetic–acoustic field in a waveguide filled
with a magnetoplasma (or
in a stratified magnetoplasma), as well as the corresponding formally adjoint
field,
are decomposed into eigenmodes. The amplitudes of incoming and outgoing
modes
for both fields are related by scattering matrices. It is shown that the
transposed
scattering matrix of one field is the inverse scattering matrix of the
other.
The fictitious formally adjoint field is temporally mapped into a
physical Lorentz-adjoint
field, whose scattering matrix is shown to be the transpose of the scattering
matrix
of the original field.
Shock waves and rarefaction waves in magnetohydrodynamics. Part 2.
The MHD system
Authors: MYONG R. S. , ROE P. L.
Published: July 2002

In Part 1 of this study, a model set exactly preserving the MHD
hyperbolic singularities was considered. By developing the viscosity
admissibility condition, it was
shown that the intermediate shocks are necessary to ensure that the planar
Riemann problem is well-posed. Here in Part 2, the MHD
Rankine–Hugoniot condition
and rarefaction-wave relations are presented in phase space, which allows
construction of analytical solutions of the planar MHD Riemann problem.
In this
process, a viscosity admissibility condition is proposed to determine
physically admissible
shocks. A complete account of MHD Hugoniot loci is given, leading to a
classification of several subproblems in which the solution patterns are
qualitatively same.
Finally, it is shown that the planar MHD Riemann problem is well-posed
using
intermediate shocks that have been considered non-evolutionary.
Nonlinear axisymmetric resistive magnetohydrodynamic equilibria with

toroidal flow
Authors: THROUMOULOPOULOS G. N.
Published: July 2002

The equilibrium of a resistive axisymmetric plasma with purely
toroidal
flow surrounded by a conductor is investigated within the framework of
nonlinear
magnetohydrodynamic theory. It is proved that (a) the poloidal
current-density
vanishes and (b) apart from an idealized case, the pressure profile

should vanish on the plasma
boundary. For the cases of isothermal magnetic surfaces, isentropic magnetic
surfaces
and magnetic surfaces with constant density, the equilibrium states obey
an
elliptic partial differential equation for the poloidal magnetic flux function,
which
is identical in form to the corresponding equation governing ideal equilibria.
The
conductivity, which can be neither uniform nor a surface quantity, results,
however,
in a restriction of the possible classes of equilibrium solutions; for
example for
the cases considered, the only possible equilibria with Spitzer conductivity
are of
cylindrical shape.
Effects of dust grain charge fluctuation on an
obliquely propagating dust acoustic solitary
potential in a magnetized dusty plasma
Authors: MAMUN A. A. , HASSAN M. H. A.
Published: July 2002

Effects of dust grain charge fluctuation, obliqueness and external magnetic
field on a finite-amplitude dust acoustic solitary potential in a magnetized
dusty plasma, consisting of electrons, ions and charge-fluctuating dust grains, are
investigated using the reductive perturbation method. It is shown that such a magnetized
dusty plasma system may support a dust acoustic solitary potential on a
very slow time scale involving the motion of dust grains, whose charge is self-
consistently determined by local electron and ion currents. The effects of dust grain
charge fluctuation, external magnetic field and obliqueness are found to modify the
properties of this dust acoustic solitary potential significantly. The implications of
these results for some space and astrophysical dusty plasma systems, especially
planetary ring systems and cometary tails, are briefly mentioned.
Interbreeding between two populations of Acartia californiensis (Copepoda: Calanoida): a laboratory study
Authors: Trujillo-Ortiz Antonio , Burton Ronald S. , de la Rosa-Velez Jorge , Correa-Sandoval Francisco
Published: July 2002

Interbreeding between two populations (Estero de Punta Banda, Baja California, Mexico (PB) and Mission Bay, California, USA (MB)) was tested using the live progeny (nauplii) of the marine calanoid copepod Acartia californiensis, in a male to female ratio of 3:1. The laboratory conditions were 18±2°C and a 12:12 h L:D cycle, during an experimental period of one week. The first filial progeny (F1) present in the replicates were used in four combinational experiments (non-hybrids: PB-PB and MB-MB, and hybrids: PB-MB and MB-PB). To investigate the production of the F2 generation, males and females were selected from F1 and 16 combinational experiments were conducted with five replicates each (non-hybrids: PBPB-PBPB and MBMB-MBMB, and hybrids: PBPB-MBMB, PBPB-PBMB, PBPB-MBPB, MBMB-PBPB, MBMB-PBMB, MBMB-MBPB, PBMB-PBPB, PBMB-MBMB, PBMB-PBMB, PBMB-MBPB, MBPB-PBPB, MBPB-MBMB, MBPB-PBMB and MBPB-MBPB). Statistical analysis for F1 showed no significant differences of the mean for live progeny between the non-hybrids and hybrids and between non-hybrids, but a significant difference between hybrids was found. For F2, the mean live progeny between non-hybrids and hybrids, between hybrids and between non-hybrids was found to be non-significant. These results show successful interbreeding between the populations studied.
Epibiont molluscs on neogastropod shells from sandy bottoms, Pacific coast of Mexico
Authors: Olabarria Celia
Published: July 2002

This study quantifies the prevalence, abundance, and spatial distribution of epibiotic molluscs on six common neogastropod species in sandy bottoms, Hexaplex nigritus, Chicoreus regius, C. erythrostomus, C. brassica, Vasum caestus and Pleuropoca princeps. A total of 1478 epibiont specimens belonging to 74 mollusc species were examined. The most of epibiotic species were typical of hard-bottoms, but a few species were typical of soft-bottoms. The results indicate H. nigritus is significantly more fouled than the other five species. This can be due to a greater availability of small hollows and a strongly ornamented shell in this species. The spatial distribution of epibionts on the neogastropod shells varied significantly among the different areas into which the shell was subdivided for this study. Fifteen sedentary epibiotic species dominated on all host shells. The costs and benefits of epibiosis are reviewed and the epibiont/host relationship appears to be principally beneficial to epibionts, without a clear benefit for hosts.
Variations in paragnath number of Hediste diversicolor from the Basque coast, in relation to habitat conditions
Authors: Garcia-Arberas L. , Rallo A.
Published: July 2002

Hediste diversicolor from several populations on the Basque coast shows great intraspecific variation in the number of paragnaths (chitinous teeth) in its proboscis. Interpopulation variation in the number of paragnaths was observed in groups I and III. Most group numbers are strongly correlated; only group VI seems to behave independently. In general, the number of paragnaths is higher than those from earlier studies on other populations at locations along the whole latitudinal gradient of the species distribution; groups II and VI are the most stable. A significant relationship was observed between the paragnath number and the granulometry of sediment: in general the number is higher in coarse sandy sediments and decreases with the fine grain fraction.
Modulation of host cell receptors: a mechanism for the
survival of malaria parasites
Authors: HOMMEL M.
Published: July 2002

Intra-erythrocytic stages of malaria parasites can alter the surface
of
their host cells and release toxins which induce the
production of cytokines, which in turn can up- or down-regulate the
expression of adhesion receptors on the surface of
microvascular endothelial cells. New adhesion receptors on endothelial

cells provide the parasite with increased chances
of survival despite an increasing level of host immunity. In order to
take advantage of these new opportunities for survival,
the parasite itself needs to make best use of its considerable ability

to vary its surface antigens and adherent molecules.
The paper describes the various players in this survival game and
articulates a working hypothesis to explain how it may all fit together.
Molecular detection of parasitic protozoa
Authors: MORGAN U. M. , THOMPSON R. C. A.
Published: July 2002

The development of molecular diagnostic methods, particularly those utilizing PCR for the detection of parasitic protozoa
will contribute greatly to the identification and control of these pathogens, by increasing speed of diagnosis, specificity and
sensitivity, reproducibility and ease of interpretation. PCR methods are not without their problems however, and there
is a need for laboratory procedures to be refined before PCR-based assays are accepted as the tools of choice for the routine
detection of protozoan parasites. The application of PCR detection to various parasites is discussed.
On the Dismounting of Seesaws
Authors: Ellis Fiona
Published: July 2002

I am concerned to examine a mode of argumentation in recent analytic philosophy which, I claim, has its origin in Hegel's ‘dialectical’ method. I give examples of this mode of argumentation in McDowell and Wiggins, followed by a formal representation which distinguishes two possible models both of which have negative and positive aspects. I consider what the commitments of the negative aspect of this approach are, and argue that the desire to avoid naturalism constitutes a common goal. I turn then to its positive aspect, making explicit and criticising some of the metaphilosophical implications contained therein. Finally, I make brief contact with Hegel.
The Reason the Universe Exists is that it Caused Itself to Exist
Authors: Smith Quentin
Published: July 2002

Philosophers have traditionally responded to the question, ‘why does the universe exist?’, in one of two ways. One response is that ‘the universe exists because God created it’ and the other response is that ‘the universe exists for no reason—its existence is a brute fact’. Both these responses are inadequate, since a third response is possible, namely, that the reason the universe exists is that it caused itself to exist. There are at least three ways the universe can cause itself to exist, by (1) a closed, simultaneous causal loop at the first instant of time, (2) beginning with a continuum of instantaneous states in a first half-open second, with each state being caused by earlier states, and (3) being caused to exist by backward causation, where a later event causes the big bang to occur. This suggests that the principle, ‘if the universe begins to exist, it has a cause’ does not support theism (as traditionally has been thought) but instead supports atheism.
Probabilistic reasoning in obsessive–compulsive and
delusional disorders
Authors: FEAR CHRISTOPHER F. , HEALY DAVID
Published: July 2002

Background. Delusional disorder (DD) and obsessive–compulsive disorder (OCD) have been
investigated in previous studies using probabilistic reasoning paradigms and abnormalities in each
group have been reported. No study to date has compared results between these groups. This
study compares patients with these disorders with those who have both phenomena.

Methods. Thirty subjects with DD, 29 with OCD and 16 with obsessive and delusional features
were compared with 30 normal controls in a study of probabilistic reasoning using two different
computer-based tasks involving a Bayesian paradigm.

Results. Deluded subjects showed a ‘jump to conclusions’ reasoning style, but on a test that
added a consequence to their choices did not differ from normals. OCD subjects deviated from
Bayesian and control norms to a greater degree than did DD subjects. In subjects with mixed
psychopathology, the presence of both phenomena appeared to ‘normalize’ these probability estimates.

Conclusions. Our findings extend those of others but require cautious interpretation as to the
role of probabilistic reasoning in the genesis of delusions or obsessions. Obsessionals in both the
OCD and Mixed groups, showed substantial deviation from Bayesian norms, suggesting that
obsessionality leads to a reasoning style that is less ‘normal’ than that of delusionals. Further
work is required to investigate clinical correlates of these findings which provide modest support
for the proposal that the combination of obsessions and delusions confers greater functional
advantages than simply having delusions or obsessions.
A survey of delusional ideation in primary-care patients
Authors: VERDOUX H. , MAURICE-TISON S. , GAY B. , VAN OS J. , SALAMON R. , BOURGEOIS M. L.
Published: July 2002

Background. To assess the prevalence of delusional ideas

in primary-care patients.

Method. A survey was carried out with the Aquitaine Sentinel

Network of general practitioners

(GPs). Consecutive practice attenders were invited to complete the

Peters et al. Delusional

Inventory (PDI-21) self-report questionnaire, designed to measure

delusional ideation in the normal

population. GPs, blind to the questionnaire results, provided

information on patients' psychiatric history.

Results. Of the 1053 attenders included in the survey, 348

(35%) had a lifetime history of psychiatric

disorder, of whom 20 (2%) had a history of broadly defined psychotic

disorder. The self-report

questionnaire was completed by 790 patients. The range of individual

PDI-21 item endorsement in

subjects with no psychiatric history varied between 5 and 70%,

suggesting that delusional ideation

is a dimensional phenomenon lying on a continuum with normality. The

main discriminative items

between psychotic and non-psychotic patients were those exploring

persecutory (OR=15·2, 95%

CI 4·3–53·7), mystic (OR=6·4,

95% CI 1·9–22·4) and guilt

(OR=5·8, 95% CI 1·5–23·2) ideas.

Conclusions. This survey demonstrates that questions that

explore delusions and hallucinations are

well-accepted by most primary-care patients. More research is needed

on psychotic disorders in

primary-care settings to improving early identification of these disorders.
Immediate memory, attention and communication
disturbances in schizophrenia patients and their
relatives
Authors: DOCHERTY NANCY M. , GORDINIER SCOTT W.
Published: July 2002

Background. Schizophrenia has been defined in part by
disturbances of thought and language. The
non-schizophrenic relatives of patients also have been found to show subtle
disturbances of
language that may be associated with vulnerability. Investigators have
hypothesized that these
phenomena in patients and their relatives are, at least in part, the result
of weaknesses in facets of
attention and memory.

Methods. The present study assessed some neuropsychological
process correlates of three different
measures of thought and language symptoms in 55 stable out-patients, using
tests of immediate
auditory memory impairment and auditory distractability, and carefully
controlling for generalized
deficit effects. A parallel assessment was made of referential communication
disturbances in 59 non-schizophrenic relatives of patients and 24 control
subjects matched to the relatives.

Results. In patients, formal thought disorder, disorganization,
and referential communication
disturbances were all associated with each other and with auditory distractability.
In addition, as
expected, referential communication disturbances were associated with immediate
auditory memory
impairment. Referential disturbance ratings for relatives were similar
in magnitude to those for the
stable out-patients, and much higher than for controls. However, the relatives'
language ratings
were not associated specifically with weaknesses in attention or memory
as measured.

Conclusions. Impairments in immediate auditory memory and attention
are associated differentially
with different types of communication disturbances in schizophrenia patients.
The cognitive
substrate for referential communication disturbances in relatives appears
to differ qualitatively from
that for patients.
Philosophy of religion: a critical survey of Internet resources
Authors: SAROT MARCEL , SCOTT MICHAEL , WISSE MAARTEN
Published: July 2002

In a survey of Internet resources available to philosophers of religion,
the authors critically discuss philosophy sites, e-journals, virtual libraries etc that
are relevant to philosophy of religion. They conclude that the Internet is
increasingly becoming a helpful and even indispensable source of information.
The realization of infinitely many universes in cosmology
Authors: HOLDER RODNEY D.
Published: July 2002

It is shown that, for certain classes of cosmological model which either
postulate or give rise to infinitely many universes, only a measure zero subset of the
set of possible universes above a given size can in fact be physically realized. It
follows that claims to explain the fine tuning of our universe on the basis of such
models by appeal to the existence of all possible universes fail.
Martha C. Pennington (ed.), Language in Hong
Kong at century's end. Hong Kong: Hong Kong University
Press, 1998. Pp. xv, 449. US $33.40.
Authors: Wang William S-Y.
Published: July 2002

Hong Kong has received much world attention in
recent years. After a century and half of colonial occupation,
it was returned to China in 1997. Before British rule,
it was an unremarkable seaside outpost of Guangzhou (Canton),
the premier city in South China. Thus, the speech of its
overwhelming majority is called “Cantonese”
in English. In fact, Hong Kong and Guangzhou share essentially
the same speech, the primary differences being lexical
choices.
Rationality, logic, and fast and frugal heuristics
Authors: Bermúdez José Luis
Published: July 2002

Gigerenzer and his co-workers make some bold and striking claims about the relation between the fast and frugal heuristics discussed in their book and the traditional norms of rationality provided by deductive logic and probability theory. We are told, for example, that fast and frugal heuristics such as “Take the Best” replace “the multiple coherence criteria stemming from the laws of logic and probability with multiple correspondence criteria relating to real-world decision performance.” This commentary explores just how we should interpret this proposed replacement of logic and probability theory by fast and frugal heuristics.
A dynamical system theory approach to cognitive neuroscience
Authors: Heinke D.
Published: July 2002

Neural organization contains a wealth of facts from all areas of brain research and provides a useful overview of physiological data for those working outside the immediate field. Furthermore, it gives a good example that the approach of dynamical system theory together with the concepts of cooperative and competitive interaction can be fruitful for an interdisciplinary approach to cognition.
Dreaming is not an adaptation
Authors: Flanagan Owen
Published: July 2002

The five papers in this issue all deal with the proper evolutionary function of sleep and dreams, these being different. To establish that some trait of character is an adaptation in the strict biological sense requires a story about the fitness enhancing function it served when it evolved and possibly a story of how the maintenance of this function is fitness enhancing now. My aim is to evaluate the proposals put forward in these papers. My conclusion is that although sleep is almost certainly an adaptation, dreaming is not.

[Hobson et al.; Nielsen; revonsuo; Solms; Vertes & Eastman]
Memory limits: “Give us an answer!”
Authors: Towse John N.
Published: July 2002

Cowan has written a meticulous and thought-provoking review of the literature on short-term memory. However, reflections on one area of evidence, that of working memory span, shows the extent to which the research debate can be circumscribed by choice of experimental paradigms.
The rhythm of the eyes: Overt and covert attentional pointing
Authors: Findlay John M. , Brown Valerie , Gilchrist Iain D.
Published: July 2002

This commentary centres around the system of human visual
attention. Although generally supportive of the position advocated in
the target article, we suggest that the detailed account overestimates
the capacities of active human vision. Limitations of peripheral
search and saccadic accuracy are discussed in relation to the division
of labour between covert and overt attentional processes.
Preconceptions and prerequisites: Understanding the function of synaptic plasticity will also depend on a better systems-level understanding of the multiple types of memory
Authors: Morris Richard G. M.
Published: July 2002

Although it is not their fault, Shors & Matzel's
attempt to review the LTP and learning hypothesis suffers from there
being no clear published statement of the idea. Their summary of
relevant evidence is not without error, however, and it oversimplifies
fundamental issues relating to NMDA receptor function. Their
attentional hypothesis is intriguing but requires a better
systems-level understanding of how attention contributes
to cognitive function.
Against suppression and clamping: A commentary on Glenberg
Authors: Ramsay Jason T. , Homer Bruce
Published: July 2002

The ability of Glenberg's model to explain the
development of complex symbolic abilities is questioned. Specifically,
it is proposed that the concepts of clamping and suppression fall
short of providing an explanation for higher symbolic processes such
as autobiographical memory and language comprehension. A related
concept, “holding in mind” (Olson 1993), is proposed as
an alternative.
Pointing the way
Authors: Ballard Dana H. , Hayhoe Mary M. , Pook Polly K. , Rao Rajesh P. N.
Published: July 2002

The majority of commentators agree that the time to focus on
embodiment has arrived and that the disembodied approach that was
taken from the birth of artificial intelligence is unlikely to provide
a satisfactory account of the special features of human intelligence.
In our Response, we begin by addressing the general comments and
criticisms directed at the emerging enterprise of deictic and embodied
cognition. In subsequent sections we examine the topics that
constitute the core of the commentaries: embodiment mechanisms, dorsal
and ventral visual processing, eye movements, and learning.
Significance testing – does it need this defence?
Authors: Palm Günther
Published: July 2002

Chow's (1996) Statistical significance is a
defence of null-hypothesis significance testing (NHSTP). The most
common and straightforward use of significance testing is for the
statistical corroboration of general hypotheses. In this case,
criticisms of NHSTP, at least those mentioned in the book, are
unfounded or misdirected. This point is driven home by the author
a bit too forcefully and meticulously. The awkward and cumbersome
organisation and argumentation of the book makes it even harder to
read.
Emergence of object representations in young infants: Corroborating findings and a challenge for the feature creation approach
Authors: Quinn Paul C.
Published: July 2002

Arguments for feature creation receive support from studies of
young infants forming category representations from perceptual
experience. A challenge for Schyns et al. will be to determine how a
feature creation system might interface with a perceptual system that
appears constrained to follow organizational principles that specify
how edge segments should be grouped into functional units of coherent
object representations.
The rage to drink, or: Frontiers of expertise
Authors: Vitouch Oliver
Published: July 2002

Current evidence shows that “talent”
is an unreliable concept, but the competing concept of
“expertise” suffers from inadequacies too: its
research designs are structurally incomplete (talent and training
are confounded) and individual factors are largely ignored. The
deliberate practice account should be advanced by investigating
in more detail the motivational and individual determinants of
successful practice.
Hebb's other postulate at work on words
Authors: Fuster Joaquín M.
Published: July 2002

The correlative coactivation of sensory inputs, Hebb's
“second rule,” probably plays a critical role in the
formation of word representations in the neocortex. It is essential to
the acquisition of word meaning. The acquisition of semantic memory
is inseparable from that of individual memory, and therefore the
two probably share the same neural connective substrate. Thus,
“content” words are represented mainly in postrolandic
cortex, where individual perceptual memories are also represented,
whereas “action” words are represented in frontal cortex,
with executive memories. The activation of a memory network may not
necessarily entail the high-frequency oscillatory firing of its cells,
though reverberation remains a plausible mechanism of short-term
memory.
Pseudo-orbits, pseudoleaves and geometric entropy of foliations
Authors: BIŚ ANDRZEJ , WALCZAK PAWEŁ
Published: July 2002

We show that the entropy of a finitely generated pseudogroup (respectively, of a foliation on a compact Riemannian manifold) can be calculated by suitable counting separated pseudo-orbits (respectively, pseudoleaves).
The rise of calypso feminism: gender and musical politics in the calypso
Authors: Mahabir Cynthia
Published: July 2002

The sky is the limit

We rising, we rising, we woman rising,

(Easlyn Orr, cited in Ottley 1992, p. 154)

In February 1999, two women of Afro-Caribbean ancestry won their respective societies' highest musical honours. On 14 February, Singing Sandra was crowned Trinidad-Tobago's Calypso Monarch 1999 – the second woman ever to win this coveted title, a full twenty-one years after the country's first woman calypso monarch, Calypso Rose. Two weeks later in the USA, Lauryn Hill received five Grammy awards, the most in any single year for a female performer or a hip-hop artist. This trend continues in Great Britain, where ‘rude girl’ DJ Patra has a growing posse of fans, and in West Africa where the pop music stylings of Benin's Angelique Kidjo and Mali's Oumou Sangaré enjoy mass followings.
Kinematic calibration of the parallel Argos mechanism
Authors: Vischer Peter , Clavel Reymond
Published: July 2002

This paper deals with the kinematic calibration of the Argos mechanism which is a novel, spherical parallel structure having 3 rotational degrees of freedom. Its design is based on 3 actuators carrying a pantograph each which are connected to the end-effector by means of 3 spherical joints. Two different calibration models are introduced. The first one models mechanical deviations in all parts except for the spherical joints and the assumption that they are moving on a perfect circle (“model 27”). The second model considers only deviations which affects the orientation of the end-effector but not its position assuming that the mechanism remains spherical (“model 9”). A measurement set-up allows to measure the full pose (position and orientation) of the end-effector with respect to its base. These measurement data are used to identify the parameters of

the two calibration models resulting in an accuracy improvement of RMS (root mean squares errors) of a factor of 5.3 for the orientation and a factor of 3.4 for the prediction of the position.
A heuristic approach to grasp planning for a multifingered hand-arm robot based on the structure of empty space
Authors: Kawarazaki Noriyuki , Hasegawa Tsutomu , Nishihara Kazue
Published: July 2002

This paper proposes a grasp planning for a multifingered hand-arm robot in the presence of obstacles. When the hand grasps an object, neither the hand nor the
arm should collide with obstacles. However, it is very difficult to generate a collision-free grasp configuration of the hand-arm robot due to its abundant degrees of freedom of motion. To overcome this difficulty, we first decompose the hand-arm robot into
the multifingered hand part and the arm part. We develop two methods of the grasp planning. In one method, a collision-free configuration of the hand part is planned first. Then,
the arm configuration is planned so as to enable the hand configuration. In the other method, the collision-free configuration of the arm part is planned first and the multi-fingered hand
configuration second. The best method is selected according to the space structure of the environment. Various heuristics are developed to improve the efficiency of the planning and implementation of the system. Simulation results are presented.
SEMIPARAMETRIC ESTIMATION OF MULTIPLE EQUATION MODELS
Authors: Picone Gabriel A. , Butler J.S.
Published: July 2002

This paper proposes a semiparametric estimator for
multiple equations multiple index (MEMI) models. Examples
of MEMI models include several sample selection models
and the multinomial choice model. The proposed estimator
minimizes the average distance between the dependent variable
unconditional and conditional on an index. The estimator
is √N-consistent and asymptotically normally distributed.
The paper also provides a Monte Carlo experiment to evaluate
the finite-sample performance of the estimator.
Growth, maturation and survival of epiphytic bromeliads in a Mexican humid montane forest
Authors: Hietz Peter , Ausserer Juliska , Schindler Gudrun
Published: July 2002

Growth and survival of plants of eight species of epiphytic bromeliad were studied over a period of 5 y in a humid montane forest in eastern Mexico using repeated photographs of branches. Growth was calculated from annual size increment and used to predict the time taken to reach fertility. Most intermediate-sized plants grew at a rate of 2–3 cm y−1, with the exception of Tillandsia deppeana, which does not invest in offshoots and grew about twice as fast. Tillandsia deppeana and two Catopsis spp. were predicted to become fertile after 11 and 9 y, respectively, T. multicaulis and T. punctulata after 13 y and T. juncea after 18 y. Individuals growing closer to the tree top tended to grow slightly faster. Relative growth rate calculated as biomass increase of the leading shoot was highest in T. deppeana and lowest in T. juncea. These differences are related to the proportion of biomass invested in offshoots, which are most numerous in T. juncea and mostly absent in T. deppeana. Fast maturation is particularly important for species growing on small and exposed branches, which experience higher mortalities caused by the breakage of their supporting branches.
Buttress formation and directional stress experienced during critical phases of tree development
Authors: CHAPMAN COLIN A. , KAUFMAN LES , CHAPMAN LAUREN J.
Published: July 2002

Patterns of buttress formation in tropical trees vary greatly within and among species. In Kibale National Park, Uganda, some form of a buttres was found on 23% of the 78 species (1785 trees) sampled from a variety of distantly related families. Large differences in buttress formation were documented within a single family and even within the same genus. Previous studies have suggested that buttresses are mechanical adaptations to counter asymmetric loads experienced during brief critical phases in a tree’s development and these persist after the need for a mechanical support has disappeared. As a tree grows from the understorey, up to the canopy, or emerges from the canopy, the potential number of occasions that a tree will experience directional stress increases. Many canopy level trees will probably have been in the vicinity of a treefall gap during their development, while emergent trees may experience gap exposure in addition to wind stresses associated with canopy emergence. Therefore, it is predicted that understorey trees should have fewer and less developed buttresses (after correcting for overall tree size) than canopy trees, which should have fewer and less developed buttresses than emergent trees. Detailed measurements of buttresses from 194 trees of eight species support this prediction. There was no evidence that trees thought to have experienced directional stress associated with selective logging almost 30 y ago had increased the number or size of existing buttresses. The pattern of buttressing in Kibale generally supports the idea that buttresses are mechanical adaptations to counter episodic asymmetric loads, and that buttresses persist after the need for a mechanical support has disappeared.
Integrating multiple problem solvers in knowledge-based systems
Authors: CHRISTODOULOU E. , KERAVNOU E. T.
Published: July 2002

Research in knowledge-based systems has shown that the use of multiple knowledge representation formalisms and reasoning mechanisms for achieving a specific task in complex domains could result in efficient and effective problem solving. This has led t
o the development of a number of general architectures and application-specific systems integrating multiple problem solvers. A problem solver is defined to be an association between a knowledge intensive (sub)task, an inference mechanism and a knowledge
representation formalism on which the inference mechanism is working to achieve the (sub)task. A knowledge-based system making use of different problem solvers should address a number of critical aspects of integration of the solvers, like interaction, in
vocation, reactiveness, learning and expandability. The aim of this paper is to distinguish and discuss essential integration aspects, and to review a number of proposed general hybrid architectures and application specific hybrid systems on the basis of
these aspects. The review shows that none of these general architectures or application specific systems directly addresses all the identified integration aspects. In general, the limitations exhibited by these systems are due to the naive form of interac
tion and invocation of the integrated solvers. We give a high level specification for a competent hybrid knowledge-based architecture that supports the identified integration aspects.
THE MEAN WAITING TIME FOR A PATTERN
Authors: Ross Sheldon M.
Published: July 2002

Consider a sequence of independent and identically
distributed random variables along with a specified set
of k-vectors. We present an expression for
E [T], the mean time until
the last k observed random variables fall within
this set. Not only can this expression often be used to
obtain bounds on E[T],
it also gives rise to an efficient way of approximating
E[T] by a simulation. Specific
lower and upper bounds for E[T]
are also derived. These latter bounds are given in terms of
a parameter, and a Markov chain Monte Carlo approach to
approximate this parameter by a simulation is indicated.
The results of this paper are illustrated by considering
the problem of determining the mean time until a sequence
of k-valued random variables has a run of size
k that encompasses each value.
TEACHING AND LEARNING IN MULTICULTURAL SCHOOLS: AN
INTEGRATED APPROACH. Elizabeth Coelho. Clevedon, UK: Multilingual
Matters, 1998. Pp. xiv + 283. $79.00 cloth, $24.95 paper.
Authors: Paulston Christina Bratt
Published: July 2002

Elizabeth Coelho's Teaching and Learning in Multicultural Schools(TLMS) is a very good book for its kind. Its primary audience is teachers at the primary and secondary level of schools in situations of cultural pluralism, the “multicultural” of the title. Schools are actually rarely multicultural, even if their students represent different cultures in contact, but rather serve as the major instrument of acculturation and assimilation into the dominant ideology. TLMSattempts to counteract this tendency by a valiant attempt of an “account of what is required to teach and learn effectively in multicultural schools” (p. x)! Coelho's ultimate goal is using the schools as agents for change in society, affirming the richness and stimulation to be found in cultural diversity.
VALIDATION IN LANGUAGE TESTING.Alister Cumming and Richard
Berwick (Eds.). Philadelphia: Multilingual Matters, 1996. Pp. 258. $29.95 paper.
Authors: Connor-Linton Jeff
Published: July 2002

This collection of papers is offered to “serve as a foundation point to illuminate the
range of considerations and approaches” in language test construct validation research (p.
12), and it succeeds admirably. The studies represent a useful sample of validation research
questions and methods. Research methods are carefully described and motivated, and many
chapters have appendices containing original research materials. Discussion and interpretation of
the results seem abridged in a few studies, but collectively the chapters present a clear and useful
picture of the complexity of construct validation research.
The paucity problem for simultaneous quadratic and biquadratic equations
Authors: TSUI W. Y. , WOOLEY T. D.
Published: July 2002

The problem of constructing non-diagonal solutions to systems of
symmetric
diagonal equations has attracted intense investigation for centuries
(see [5, 6] for a
history of such problems) and remains a topic of current interest (see,
for example,
[2–4]). In contrast, the problem of bounding
the number of such non-diagonal
solutions has commanded attention only comparatively recently, the first
non-trivial
estimates having been obtained around thirty years ago through the sieve
methods
applied by Hooley [10, 11] and Greaves

[7] in their investigations concerning sums
of two kth powers. As a further contribution to the problem of
establishing the
paucity of non-diagonal solutions in certain systems of diagonal diophantine

equations, in this paper we bound the number of non-diagonal solutions
of a system
of simultaneous quadratic and biquadratic equations. Let
S(P) denote the number of
solutions of the simultaneous diophantine equations

formula here

with 0[les ]xi,
yi[les ]P(1[les ]i[les ]3),
and let
T(P) denote the corresponding number of
solutions with (x1, x2, x3)

a permutation of (y1, y2, y3).

In Section 4 below we establish the upper and lower bounds for
S(P)−T(P) contained in the following
theorem.
The global wood market, prices and plantation investment: an examination drawing on the Australian experience
Authors: Clark Judy
Published: July 2002

A global wood shortage generating real inflation-adjusted price increases for wood has been a long and widely-held expectation. This paper assesses the validity of this view by examining global trends in wood and wood-products consumption, developing a model to explain movements in wood prices and testing it empirically. No evidence was found of increasing real prices for wood over the long-term, indicating that there is no looming global wood shortage. A global wood shortage is not predicted because technology is increasing resource productivity, enabling wood products to be made using less wood, and also increasing wood supply. It is superficial to interpret this to mean that there is little to worry about from a native forest biodiversity perspective. The analysis presented in this paper suggests that real prices for wood are likely to continue to fall. This will discourage commercially-driven investment in plantation establishment on existing agricultural land. But industrial pressure will continue for a wood resource that is attractive in cost and quality terms, increasing the risk of biodiversity loss through intensification of native forest management and clearing of native forests for plantations. It is prudent to consider approaches that encourage plantation investment on existing agriculture land using the price mechanism. Currently, much private sector plantation investment is based on price expectations derived from an incorrect view of an imminent global wood shortage. Withdrawing old-growth forests from commodity wood supply is likely to increase wood prices in line with widely-held, though apparently false, expectations and also deliver an absolute best ecological outcome. As increasing volumes of wood become available from maturing plantations, government policy changes will be required to ensure that levels of logging in native forests actually decline rather than new markets being found for native forest wood. Despite its strategic commercial importance, little is known about the potential of the existing global plantation estate to supply wood. Addressing this information gap is a timely task that would enhance industry policy and clarify future plantation investment requirements.
Understanding local people's use of time: a pre-condition for good co-management
Authors: COLFER CAROL J. PIERCE , WADLEY REED L. , VENKATESWARLU P.
Published: July 2002

Development of management plans collaboratively with local people (e.g. co-management) is now an important means of protected area conservation. Yet formal protected area managers often need more specific information about the local people with whom they want to co-manage resources. We propose wider use of a method, which we describe, for studying time allocation, as an early step in the co-management of conservation areas. Use of time allocation data in co-management is illustrated from a conservation project in Danau Sentarum Wildlife Reserve (DSWR) in West Kalimantan, Indonesia. Data from spot observations were analysed at three levels, namely those of 'macro-categories' (production, reproduction and leisure), an intermediate level (e.g. agriculture and food preparation), and that of individual activities (such as fishing, collection of forest foods and hunting).

In the DSWR, the allocation of time differed according to gender, ethnicity and seasonality, throughout the year of the study. Our experience suggests that knowledge of such patterns of behaviour can help conservation area managers to understand local people's needs and desires better, improve managers' rapport with local people, and make better cooperative plans with local people.