bluuebunny/crossref_metadata_2025 huggingface dataset:
About saccade generation in reading
Authors: Vitu Françoise
Published: July 2002

In their model, Findlay & Walker propose that where and when the eyes move is determined by two relatively independent processing streams. Whereas both saccade direction and amplitude result from a low-level visual analysis of the peripheral visual stimulation, saccade latency results mainly from higher-level processes related to processing of the central information. In the present commentary, reading eye movement data are put forward as evidence against a strict autonomy of “Where” and “When” processing streams. First, saccade direction and amplitude might be modified by high-level processes related to word identification. Second, the direction of a saccade directly affects its latency.
An analytic counterexample to the KAM theorem
Authors: BESSI UGO
Published: July 2002

We study the non-existence of KAM tori for quasi-integrable, analytic Lagrangians. Let ${\cal L}\colon {\bf T}^m\times{\bf R}^m \to {\bf R}$, ${\cal L} (Q,\dot{Q})=\tfrac{1}{2}\vert\dot{Q}\vert^2+h(Q)$ and let $\bar\omega\in{\bf R}^m$ be a frequency exponentially close to resonances. We find $h$ analytic of norm arbitrarily small such that ${\cal L}$ has no invariant torus of frequency $\bar\omega$ projecting diffeomorphically on $\T^m$
Parabolic iterated function systems
Authors: MAULDIN R. D. , URBAŃSKI M.
Published: July 2002

In this paper we introduce and explore conformal parabolic iterated function systems. We define and study topological pressure, Perron–Frobenius-type operators, semiconformal and conformal measures and the Hausdorff dimension of the limit set. With every parabolic system we associate an infinite hyperbolic conformal iterated function system and we employ it to study geometric and dynamical features (properly defined invariant measures for example) of the limit set.
Dynamics of sub-hyperbolic and semi-hyperbolic rational semigroups and skew products
Authors: SUMI HIROKI
Published: July 2002

We consider dynamics of sub-hyperbolic and semi-hyperbolic semigroups of rational functions on the Riemann sphere and will show some no wandering domain theorems. The Julia set of a rational semigroup in general may have non-empty interior points. We give a sufficient condition that the Julia set has no interior points. From some information about forward and backward dynamics of the semigroup, we consider when the area of the Julia set is equal to zero or an upper estimate of the Hausdorff dimension of the Julia set.
A bound on the fixed-point index for surface mappings
Authors: KELLY MICHAEL R.
Published: July 2002

In this paper we consider the class of
surface mappings consisting of those maps which have the least number of
fixed points possible among all maps in their homotopy class.
When the surface has non-empty boundary, we show that for mappings
in this class the index of a fixed point is bounded above by $1$
and below by $2\chi -1$.
This generalizes a well known result for pseudo-Anosov homeomorphisms.
A proof of a Jiang–Guo type inequality is also given.
Graph substitutions
Authors: PREVITE JOSEPH P.
Published: July 2002

In 1984, Gromov (see [4] and [6]) introduced the idea of subdividing a ‘branching’ polyhedron into smaller cells and replacing these cells by more complex objects, reminiscent of the growth of multicellular organisms in biology. The simplest situation of this kind is a graph substitution which replaces certain subgraphs in a graph $G$ by bigger finite graphs. The most basic graph substitution is a vertex replacement rule which replaces certain vertices of $G$ with finite graphs. This paper develops a framework for studying vertex replacements and discusses the asymptotic behavior of iterated vertex replacements, the limit objects, and the induced dynamics on the space of infinite graphs from the viewpoint of geometry and dynamical systems.
Random iterations of polynomials of the form $z^2+c_n$: connectedness of Julia sets
Authors: BRÜCK RAINER , BÜGER MATTHIAS , REITZ STEFAN
Published: July 2002

For a sequence $(c_n)$ of complex numbers we consider the quadratic polynomials $f_{c_n}(z):=z^2+c_n$ and the sequence $(F_n)$ of iterates $F_n:= f_{c_n} \circ \dotsb \circ f_{c_1}$. The Fatou set $\mathcal{F}_{(c_n)}$ is by definition the set of all $z \in \widehat{\mathbb{C}}$ such that $(F_n)$ is normal in some neighbourhood of $z$, while the complement of $\mathcal{F}_{(c_n)}$ is called the Julia set $\mathcal{J}_{(c_n)}$. The aim of this paper is to study the connectedness of the Julia set $\mathcal{J}_{(c_n)}$ provided that the sequence $(c_n)$ is bounded and randomly chosen. For example, we prove a necessary and sufficient condition for the connectedness of $\mathcal{J}_{(c_n)}$ which implies that $\mathcal{J}_{(c_n)}$ is connected if $|c_n| \le \frac{1}{4}$, while it is almost surely disconnected if $|c_n| \le \delta$ for some $\delta>\frac{1}{4}$.
Can the State Create Cooperation?: Problems of Reforming the Labor Supply in France
Authors: CULPEPPER PEPPER D.
Published: July 2002

Governments in the advanced industrial countries increasingly rely on supply-side reforms to intervene in the economy.
This article examines one such reform, that of vocational education and training in France, whose successful
implementation required that private actors cooperate not with the state, but with each other. As demonstrated through an
empirical analysis of two employment zones, theories of institutional design that underscore the necessity of
sanctioning cannot explain the successful emergence of cooperation, because new sanctioning regimes lack credibility
under the uncertain conditions of economic reform. The primary obstacle to successful implementation of these reforms
is uncertainty about the consequences of reciprocal cooperation, and the article highlights the mutual roles of states
and employers' associations in overcoming this uncertainty. Active collaboration between policymakers and employers'
associations, which have uniquely good access to private information about firms, is necessary to enable state policies
to target those firms which are the most likely potential cooperators.
Policy Regimes and Policy Change
Authors: WISON CARTER A.
Published: July 2002

The evolution of public policies in the United States has been characterized as a process involving long periods of
stability followed by abrupt episodes of substantial change. In this project, we identify strands in the literature and
synthesize policy theories into a policy regime model useful in explaining both stability and change. This model
focuses on power arrangements, policy paradigms and organization - factors that operate to maintain long periods of
stability. We demonstrate how stressors - catastrophic events, economic crises, demographic changes, shifts in modes
of production, and others - impact policy regimes and create pressures for change. We argue that the process of policy
regime change - the abrupt episodes of substantial change - occurs with changes in the policy paradigm, alterations
in patterns of power and shifts in organizational arrangements. The old policy regime disintegrates and the new one
emerges with a new policy paradigm, new patterns of power and new organizational arrangements that operate to
maintain long periods of stability.
Beyond Legalism? Policy Ideas, Implementation Styles and Emulation-Based Convergence in Canadian and U.S. Environmental Policy
Authors: HOWLETT MICHAEL
Published: July 2002

Past studies of the dynamics of U.S.-Canada environmental policy and policy-making have found little evidence of
‘weak’ convergence in this sector; that is, of Canadian policy moving towards the U.S. model of adversarial legalism,
an implementation style based upon procedural policy instruments such as action-forcing statutes, citizen suits, and
judicial activism. However, recent efforts at de-regulation and the reformation of government in the U.S., and moves
towards multi-stakeholder policy-making in Canada, have altered the standard against which trends towards Canadian^
American convergence must be assessed. These reforms have moved the U.S. environmental regulatory system closer
to that existing in Canada, in which regulations and other elements of the environmental regime are developed through
negotiation rather than litigation. Since Canadian environmental implementation has also been altered over the same
period, however, it is argued that a form of ‘strong’ convergence is emerging, in which both countries are moving not
towards each other but towards a third, common, style, that associated with the development of self-regulation and
voluntary initiatives under the influence of New Public Management ideas and principles.
Devolved Social Security Systems: Principal-agent versus multi-level governance
Authors: Mabbett Deborah , Bolderson Helen
Published: July 2002

This paper presents an analytical framework for comparing patterns of devolution to subnational governments and autonomous social insurance institutions in social security systems. The framework has two components. One is an analysis of financial structures along the dimensions of financial autonomy (indicated by the extent to which the administering institution raises its own revenue or depends on central grants) and financial responsibility (indicated by whether marginal costs are borne by the administering institution). The other component of the framework concerns the assignment of policy-making power; in particular, we contrast the effects of competitive and cooperative modes of devolution. The discussion uses examples from Denmark, France, Germany, the Netherlands and the USA. While we looked for ‘principal-agent’ relationships between central governments and administering institutions, we found that more complex multi-level governance structures prevailed in most cases.
Managing food shopping and cooking: the experiences of older Swedish women
Authors: SIDENVALL BIRGITTA , NYDAHL MARGARETHA , FJELLSTRÖM CHRISTINA
Published: July 2002

The aim of the research reported in this paper was to study older Swedish women's experiences of managing food shopping and cooking as part of an independent life in different family situations. The research approach was qualitative, using informal ethnographic interviews and thematic analysis. Twenty-three single-living and 18 cohabiting Swedish women, aged 64–67, 74–77 and 84–87, participated. They valued being active through continuing with familiar routines whereby they could live independently. They gained physical exercise and social contacts when they went shopping. Well-known foods and traditional dishes were preferred as they enabled them to proceed from familiar routines. Economical thinking related to money and their own work guided their choice of food. Lack of strength made some, particularly the older informants and those living alone, dependent on local shops, and they simplified their cooking, while others had more freedom of choice when they shopped together with their husbands. The implications of the research for services which help older women, particularly those who live alone or who have been recently bereaved, are discussed.
A culturally-relevant theoretical framework for the study of successful ageing
Authors: TORRES SANDRA
Published: July 2002

In spite of the many studies conducted over the past decades, the field of
inquiry known as cross-cultural gerontology remains atheoretical. This is
because of its shortcomings in generating culturally-relevant theoretical
frameworks of its own. In this article, I address this failure and adapt
Kluckhohn's model of value orientations for use in the study of ageing-related
concepts. I discuss possible applications of the adapted model and, in
particular, its application to one of the most frequently debated concepts in
gerontology, successful ageing. In the light of this discussion, I conclude that
the culturally-relevant theoretical framework hereby proposed could lead to
the rectification of the current atheoretical predicament of cross-cultural
gerontology.
Sooner rather than later? Younger and middle-aged adults preparing for retirement
Authors: ANDERSON MICHAEL , LI YAOJUN , BECHHOFER FRANK , McCRONE DAVID , STEWART ROBERT
Published: July 2002

During the 1990s, the British population has been urged by government and
financial institutions to make more personal preparation for retirement and to
begin doing so while they are still relatively young. This paper, set within a
wider analysis of people's long-term planning behaviour, investigates the
extent to which a sample of the general population of Kirkcaldy in Scotland,
mostly aged between 30 and 49, has given thought to the question of
retirement, feels they have made financial preparation for it, and also how
comfortable they expect retirement to be. While it seems likely that early
planning for retirement is more common today than 20 years ago, there
remain substantial sections of the population, including – but going well
beyond – many in lower income groups, who appear not to be preparing, for
varying combinations of reasons (including family responsibilities, personal
history, cultural and general orientation to life). The study concludes that
planning for retirement must be seen as part of planning as a whole, and that
the propensity to plan is the outcome of a complex web of material, social,
cultural and psychological factors. This suggests that even very high profile
urging from politicians and financial institutions is unlikely to deliver
adequate pensions for significant sections of the UK population.
‘Britain's Irish Question: Britain's European Question?’ British-Irish relations in the context of European Union and The Belfast Agreement
Authors: MEEHAN ELIZABETH
Published: July 2002

If students of world politics can be reasonably accused of ignoring the Troubles in Northern Ireland—in part because they seemed to have little to do with the larger East-West confrontation and partly because they were so obviously about something distinctly national in character—then by the same token specialists on Northern Ireland can justly be accused of a certain intellectual parochialism and of failing to situate the long war within a broader global perspective. The quite unexpected outbreak of peace however only emphasizes the need for a wider understanding of the rise and fall of the Northern Irish conflict. This article explores the relationship between the partial resolution of the Irish Question—as expressed in the Good Friday Agreement of 1998—and the changing character of the European landscape. Its central thesis is that while there were many reasons for the outbreak of peace in the 1990s, including war weariness, it is difficult to understand what happened without situating it in a larger European framework and the new definition of sovereignty to which the EU has given birth.
American neutral rights reappraised: identity or interest in the foreign policy of the early Republic?
Authors: SOFKA JAMES
Published: July 2002

This article analyses the early American commitment to maintaining its neutral rights from several theoretical perspectives. Rejecting recent constructivist interpretations as unsubstantiated by the empirical evidence, it concludes that early American leaders largely mirrored traditional eighteenth century mercantilist practices to suit the interests of the United States. In particular, Jefferson's ‘two-tiered’ approach to the international system was based on astringent calculations of power rather than prevailing notions of ‘republicanism’. This ideology, while manifest in partisan rhetoric, had little measurable impact on the conduct of early American neutral rights policy. By focusing on the relationship of theory and practice in this context, this article offers a case study of the role of norms and ideology in the shaping of foreign policy in a republican state.
Strategic culture as context: the first generation of theory strikes back
Authors: GRAY COLIN S.
Published: July 2002

‘Strategic Culture as Context: The First Generation of Theory Strikes Back’ takes the scholarly argument about the study, and meaning, of strategic culture to a new stage. Specifically, this article is a direct reply to recent criticisms of so-called first-generation theorists of strategic culture. The author reconsiders both the subject of strategic culture, and what he first wrote about it fifteen and more years ago. He finds that although there is noteworthy room for improvement in what he wrote then, the recent theorising by Alastair Iain Johnston, in particular, rests upon a misunderstanding of the nature, character, and ‘working’ of strategic culture. Of particular note is the insistence by Johnston on a separation of ideas from behaviour, for the dominant purpose of developing falsifiable theory. ‘Strategic Culture as Context,’ therefore, revisits in some detail questions of definition, with particular reference to the ideas-behaviour nexus. The article proceeds both to register arguments that should advance understanding of how strategic culture ‘works,’ and to suggest a better set of discriminators, different perspectives, for better consideration of evidence of strategic culture. Overall, the article suggests that strategic culture provides context for understanding, rather than explanatory causality for behaviour.
Line shape modeling of multielectron ions in plasmas
Authors: LOBODA P.A. , LITVINENKO I.A. , BAYDIN G.V. , POPOVA V.V. , KOLTCHUGIN S.V.
Published: July 2002

A density-matrix theoretical model to calculate
spectral line profiles of general multielectron ions in
plasmas is described. The line-profile calculation involves
electron collisional and radiative relaxation of ionic
states, the emitter's motion (Doppler effect) and its
interaction with a quasi-static ion microfield. Using the
LineDM computer package implementing this model, line-profile
calculations of the K- and L-shell transitions
in Al XII, Ar XVII, Ar XVI, Cu XX, and Xe XLV ions have been
performed in the context of plasma diagnostic issues of recent
laboratory experiments. Comparisons of the calculated line profiles
with experimental and other theoretical data show the applicability
of the model and package for the detailed computational analysis
of line radiation spectra from multielectron emitters in hot
dense plasmas.
PD control with feedforward compensation for robot manipulators: analysis and
experimentation
Authors: Santibañez Victor , Kelly Rafael
Published: July 2002

One of the
simplest and natural appealing motion control strategies for robot manipulators
is the PD control with feedforward compensation. Although successful experimental
tests of this control scheme have been published since the
beginning of the eighties, the proof of global asymptotic stability
has remained unattended until now. The contribution of this paper
is to prove that global asymptotic stability can be guaranteed
provided that the proportional and derivative gains are adequately selected.
The performance of the PD control with feedforward compensation evaluated
on a two degrees-of-freedom direct-drive arm appears as fine as
the classical model-based computed torque control scheme.
Ultrasonic classification and location of 3D room features using maximum likelihood estimation - Part II
Authors: Hong Mun-Li , Kleeman Lindsay
Published: July 2002

This paper is part II of a paper published in the previous issue
of Robotica. This part proceeds from the assumption that 3D features
have been calssified into either a plane, a 2D corner type I or II, or a 3D
corner using the Maximum Likelihood Estimator. The location of the 3D features
from the results of the Maximum Likelihood Estimation are derived here.
Experimental results characterising the ultrasonic sensor and its application
to a robot localisation problem are presented in this paper.
Dynamic instant gait stability measure for quadruped walking robot
Authors: Koo Tae-Wan , Yoon Yong-San
Published: July 2002

A mathematic model is developed for a quadruped walking robot to investigate the dynamic stability considering all the inertial effects in the system including those of legs. The dynamic model is derived based on Lagrange's equation using matrix-vector notations for the simpler expression. Then an instant gait stability measure is proposed to
apply to dynamic gait as well as static gait. The gait stability measure is obtained from the angular momentum of the system about the supporting edges in the quadrupedal gait of +x type. The validity of the gait stability measure is examined along with the gait stability analysis for several representative gait parameters using the developed dynamic model.
NON-GAUSSIAN LOG-PERIODOGRAM REGRESSION
Authors: Velasco Carlos
Published: July 2002

We show the consistency of the log-periodogram
regression estimate of the long memory parameter for long
range dependent linear, not necessarily Gaussian, time
series when we make a pooling of periodogram ordinates.
Then, we study the asymptotic behavior of the tapered periodogram
of long range dependent time series for frequencies near
the origin, and we obtain the asymptotic distribution of
the log-periodogram estimate for possibly non-Gaussian
observation when the tapered periodogram is used. For these
results we rely on higher order asymptotic properties of
a vector of periodogram ordinates of the linear innovations.
Finally, we assess the validity of the asymptotic results
for finite samples via Monte Carlo simulation.
IDENTIFICATION OF THE BINARY CHOICE MODEL WITH MISCLASSIFICATION
Authors: Lewbel Arthur
Published: July 2002

Misclassification in binary choice (binomial response)
models occurs when the dependent variable is measured with
error, that is, when an actual “one” response
is sometimes recorded as a zero and vice versa. This paper
shows that binary response models with misclassification
are semiparametrically identified, even when the probabilities
of misclassification depend in unknown ways on model covariates
and the distribution of the errors is unknown.
LOCAL SEMIPARAMETRIC EFFICIENCY BOUNDS UNDER SHAPE RESTRICTIONS
Authors: Tripathi Gautam
Published: July 2002

Consider the model y = x′β0
+ f*(z) + ε, where ε [d over =]
N(0, σ02). We calculate the smallest
asymptotic variance that n1/2 consistent regular
(n1/2CR) estimators of β0 can
have when the only information we possess about f*
is that it has a certain shape. We focus on three particular cases:
(i) when f* is homogeneous of degree r,
(ii) when f* is concave,
(iii) when f* is decreasing.
Our results show that in the class of all n1/2CR
estimators of β0, homogeneity of
f* may lead to substantial asymptotic efficiency gains
in estimating β0. In contrast, at least
asymptotically, concavity and monotonicity of f* do
not help in estimating β0 more efficiently, at
least for n1/2CR estimators of
β0.
Integrating liana abundance and forest stature into an estimate of total aboveground biomass for an eastern Amazonian forest
Authors: Gerwing Jeffrey John , Farias Damião Lopes
Published: July 2002

This study provides an estimate of aboveground live biomass for an intact eastern Amazonian forest. An allometric regression biomass equation was developed to estimate the aboveground biomass of live lianas. This equation, together with a previously published equation for trees, was then used to estimate the contributions of lianas and trees to the total biomass of forest patches in four stature classes: gap (openings in the canopy of at least 25 m2 with the dominant vegetation < 3 m high), low (3–15 m canopy height), medium (15–25 m canopy height), and high (> 25 m canopy height). Total stand-level biomass was estimated as the weighted average of the stature classes. In 130 ha of surveyed forest, forest stature classes were found in the following proportions: gap phase 8%; low stature 31%; medium stature 44%; and high stature 17%. Total aboveground biomass was found to be three times higher in high stature forest than in low. Liana biomass, however, showed the opposite result, being three times higher in low stature forest. Stand-level aboveground live biomass was estimated at 314 t ha−1 of which 43 t ha−1 (14%) was lianas. Liana leaf area index (LAI) ranged from 1.3 m m−2 in high stature forest to 5.3 m m−2 in low stature. Abundant lianas are generally interpreted as a sign of past forest disturbance. As forests throughout the Amazon basin are increasingly disturbed through human activities, it is likely that their biomass will be underestimated if the contribution of lianas is ignored.
Diversity and distribution of lianas in a neotropical rain forest, Yasuní National Park, Ecuador
Authors: NABE-NIELSEN JACOB
Published: July 2002

Lianas (woody vines) contribute substantially to the diversity of woody
plants in Yasuní National Park, Eastern Ecuador. In total 606
individuals, belonging to 138 species, were found in two 20-m × 100-m
plots. The liana diversity was higher than in any comparable study, but the
density was relatively low. Sapindaceae and Leguminosae were the most
species-rich families, whereas Leguminosae and Celastraceae were the most
abundant families. The number of liana individuals as well as the number of
liana species was partially explained by forest structure, but 92% of the
variation in number of liana species depended on the number of liana
individuals. Areas with high density of small trees had high liana density,
and areas with a high number of tree saplings had a relatively high diversity
of climbing lianas. The probability of trees being colonized by lianas
increased with tree diameter. The presence of one liana on a tree increased
its risk of being colonized by additional lianas.
Diversity and structure of the arthropod fauna within three canopy epiphyte species in central Panama
Authors: Stuntz Sabine , Ziegler Christian , Simon Ulrich , Zotz Gerhard
Published: July 2002

The arthropod fauna inhabiting 90 individuals of three different species of epiphyte was investigated in the moist lowland forest of the Barro Colorado National Monument in Panama. In total, 3694 arthropods belonging to 89 morphospecies and 19 orders were collected. While arthropod abundance was primarily a function of host plant biomass irrespective of epiphyte species, there were pronounced differences in species richness, species composition and guild structure of the arthropod faunas of the three epiphyte species. Although all study plants were growing in close proximity on the same host tree species, there was remarkably little overlap in the species assemblages across epiphyte taxa. The inhabitant species also differed dramatically in their ecological functions, as feeding guild and hunting guild analyses indicated. The influence of plant size, structure and impounded leaf litter on arthropod diversity is discussed. We conclude that epiphytes are microhabitats for a diverse and numerous fauna, and that different species of epiphytes foster both taxonomically and ecologically very distinct arthropod assemblages.
Seed dispersal of Asplundia peruviana (Cyclanthaceae) by the primate Saguinus fuscicollis
Authors: KNOGGE CHRISTOPH , HEYMANN ECKHARD W. , TIRADO HERRERA EMÉRITA R.
Published: July 2002

The reproductive success of plants depends to a very large degree on the quantity and quality of seed dispersal. If dispersal is by animals (zoochory), characteristics of fruits such as colour, size, shape and nutritional content have been shown to influence the likelihood of visitation by frugivores or the rate of fruit removal (e.g. Fuentes 1994, Howe 1983, Murray et al. 1993). While these characteristics function in the attraction of dispersers, plants may also evolve characters that manipulate the behaviour or the physiology of dispersers after the consumption of fruits and the ingestion of seeds. An example of such post-consumption manipulation of dispersers' behaviour by plants is provided by mistletoes. The viscous mistletoe seeds stimulate the disperser (usually birds) to either rub the cloaca (when seeds are passed through the gastro-intestinal tract) or the bill (when seeds are regurgitated) on a branch (e.g. Reid 1991). It has also been proposed that fruits might manipulate the disperser's physiology by including laxatives that determine the optimal passage time through the disperser's gut (Murray et al. 1994), although this view has recently been challenged (Witmer 1996).
Ecosystem structure in the Brazilian Cerrado: a vegetation gradient of aboveground biomass, root mass and consumption by fire
Authors: DE CASTRO ELMAR ANDRADE , KAUFFMAN J. BOONE
Published: July 2002

Conversion to permanent agriculture is rapidly occurring over vast areas of the 1.8 million km2; Brazilian Cerrado; a region that is naturally a mosaic of grasslands, savannas and evergreen tropical woodlands. Yet, few studies have quantified total biomass of plant communities in this ecosystem, particularly the belowground component; a C pool of potential global significance. Total biomass (aboveground and belowground), and the quantity of biomass consumed by fires were measured in four plant communities comprising a vegetation gradient from pure grassland (campo limpo) to a woodland with a closed canopy of tall shrubs and scattered trees (cerrado denso) near Brasilia, DF, Brazil. Total aboveground biomass (TAGB) increased along this gradient from 5.5 Mg ha-1 in campo limpo to 29.4 Mg ha-1 in cerrado denso. Vegetation structure varied among communities; trees were nonexistent in campo limpo, but were at a density of 1000 ha-1 and a biomass of 12.9 Mg ha-1 in cerrado denso. Fires consumed 92 and 84% of the TAGB in campo limpo (pure grassland) and campo sujo (savanna), respectively. In cerrado aberto and cerrado denso, trees and tall shrubs were little affected by fire. Combustion factors of the TAGB in these communities was 54 and 33%, respectively. The total biomass consumed by fire ranged from 5.0 Mg ha-1 in campo limpo to 13.5 Mg ha-1 in cerrado aberto. Compared to other widespread Brazilian ecosystems (tropical dry forest and evergreen forest), the Cerrado has a lower aboveground biomass. The TAGB of cerrado denso is > 9% of that of Amazonian tropical evergreen forest. The total quantity of biomass consumed by fire, and hence emissions to the atmosphere is lower in intact Cerrado communities compared to fires in slashed tropical forest.
Consumption of macro-fungi by invertebrates in a Mexican tropical cloud forest: do fruit body characteristics matter?
Authors: Guevara Roger , Dirzo Rodolfo
Published: July 2002

The emphasis of antagonistic fungus–consumer interactions to date has been on temperate taxa and predominantly zoocentric, neglecting the effects on the fungal component. These interactions are expected to be especially complex and diverse in the tropics, where both components display their greatest diversity. Variability in fungivory (apparent biomass consumed) of understorey basidiomycetes in a tropical cloud forest was investigated to test whether this could be explained (at the proximate level) by apparency-related characteristics of the aboveground structures (colour of pileus, stipe and hymenium; size and aggregation), as has been suggested for plant–herbivore relationships. Considerable interspecific variation in fungivory was detected (range 0–50%). Cluster analysis showed that neighbouring clusters had dissimilar levels of fungivory. Such clusters were similar in colour attributes of aboveground structures, but differed in aggregation size and apparent biomass. A quantitative analysis also showed that colour attributes were not strongly associated with the observed variation of consumption levels, whereas apparent biomass and aggregation size did correlate with the observed variation in fungivory. Furthermore, specific identity correlated with fungivory. It was concluded that coloration patterns may not be important for fungivory, whereas genet size and species identity (probably via characteristics unrelated to apparency, such as mycotoxins and nutritional value) seemed to be critical factors.
Tanzanian forest tree plot diversity and elevation
Authors: Lovett Jon C.
Published: July 2002

Observed variation in species richness on ecological gradients and between
regions has attracted several different explanations. Climatic factors, such as
energy availability, precipitation and mean annual temperature, are frequently
cited to explain differences in species richness (Wright et al. 1993). The relative
amount of variation in these variables may be of importance as well as absolute
values (Stevens 1989, 1992). Alternatively, the history of colonization and
extirpation have been used to explain regional variation in diversity (Guo et al. 1998; Latham & Ricklefs 1993a, b). Area is an important factor, for example
on an elevational gradient the tops of mountains are not only cooler than the
bottoms, but they are also much smaller (Rahbek 1997).
ON MEASURE OF SYSTEM INTERVAL AVAILABILITY
Authors: Mi Jie
Published: July 2002

Let [script S] be a system that can be in one of
two states, up or down. We can interpret the up state as
the working state and the down state as the nonworking
state for system [script S]. Assume the system [script S] is
up at time t = 0. Denote the elapsed time from zero
until [script S] enters down state by U1,
and the elapsed time from then until [script S] is up again
by D1. The interval
[0,U1 + D1)
is called cycle 1, and, at that point, cycle 2 starts and
the sequence is repeated so on and so forth. In general,
the up time and down time in the jth cycle are
denoted by Uj and
Dj, respectively, for j
≥ 1. We can introduce a binary process {X(t),
t ≥ 0} to describe the state of [script S] at time
t using X(t) = 1(0) to indicate
[script S] is up (down). Many problems require finding
the probability that [script S] is up at time t,
that is, P(X(t) = 1). However,
an even more interesting question to answer is what the
probability is that [script S] is in the up state in an
interval of length w starting at time t,
that is, P(X(s) = 1,
t ≤ s ≤ t + w).
Due to the complexity of this problem, no explicit expressions
are available for most systems even in the case where
(Uj, Dj),
j ≥ 1 are i.i.d. Fortunately, in practice engineers are more
interested in the long-run properties of the above two probabilities.
SECOND LANGUAGE ATTRITION IN JAPANESE CONTEXTS. Lynn
Hansen (Ed.). Oxford: Oxford University Press, 1999. Pp. xi + 219. $35.00 cloth.
Authors: Ohta Amy Snyder
Published: July 2002

Researchers interested in second language attrition have studied a wide variety of bilingual
speakers, ranging from foreign language students who learned a language through classroom
study to those who have developed high proficiency during life abroad. What these studies have in
common is their investigation of questions related to bilingual speakers' loss of L2
knowledge or proficiency. Hansen's collection of papers presents research on a range of
bilingual speakers who have the Japanese language in common, whether that language is their L1
or L2. The book is divided into two major sections. The first section, consisting of three papers,
presents studies of Japanese children of elementary school age who learned English while living
abroad but who have returned to Japan. This section will be of interest to EFL teachers of
children as well as to L2 researchers. The four papers in the second section of the book examine
the attrition of Japanese by adults. Most of these adults became subjects while residing in the
United States after working or studying in Japan. The adults studied in these chapters had a
variety of different combinations of exposure and formal study and also a broad range of years
away from Japan, from 9 months to 30+ years. Additionally, the subjects of one study never lived
in Japan at all but learned Japanese during Japan's occupation of Micronesia.
ACCENT, INTELLIGIBILITY, AND COMPREHENSIBILITY
Authors: Derwing Tracey M. , Munro Murray J.
Published: July 2002

This study was designed to extend previous research on the relationships among
intelligibility, perceived comprehensibility, and accentedness. Accent and comprehensibility
ratings and transcriptions of accented speech from Cantonese, Japanese, Polish, and Spanish
intermediate ESL students were obtained from 26 native English listeners. The listeners were
also asked to identify the first language backgrounds of the same talkers and to provide
information on their familiarity with the four accents used in this study. When the results of this
study were compared with the Munro and Derwing (1995, Language Learning,
45, 73–97) study of learners of high proficiency, speaker proficiency level did
not appear to affect the quasi-independent relationships among intelligibility, perceived
comprehensibility, and accentedness; however, the relative contributions of grammatical and
phonemic errors and goodness of prosody differed somewhat. Ability to identify the
speakers' first languages was influenced by familiarity.
INCIDENTAL VOCABULARY ACQUISITION FROM ORAL
AND WRITTEN DIALOGUE JOURNALS
Authors: Brown Cheryl , Sagers Sherri L. , LaPorte Carrie
Published: July 2002

This paper is in answer to Ellis's (1994) call for more research about vocabulary
acquisition from oral input in four areas. It is a hypothesis-generating study of nine advanced
university EFL learners' incidental vocabulary acquisition from oral and written dialogue
journals over a semester's time. All teacher and student entries in the two types of journals
were transcribed and analyzed using WordCruncher (1993). The analyses compare the
characteristics of the input to the learners in the two modes as well as quantitative and qualitative
evidence of vocabulary acquisition by the learners from the two modes. Findings of this study
indicate several specific places (14 statements) where further research could be undertaken. These
fit in three of the areas Ellis named for exploration: (a) “the nature of the input,”
(b) “the role of interaction,” and (c) “individual learner factors” (p.
1). The findings suggest measures that can be used for quantitative and qualitative evidence of
vocabulary acquisition from natural sources
Counting nouns and verbs in the input: differential frequencies, different kinds of learning?
Authors: SANDHOFER CATHERINE M. , SMITH LINDA B. , LUO JUN
Published: July 2002

Previous research has focused on evaluating the nouns and verbs in
parents' input through type/token ratios. This research offers an
additional means of evaluating parent speech by first examining the
frequencies of individual nouns, verbs and descriptors and second
examining the learning task presented to children. Study 1 examines 25
transcripts from the CHILDES database of English-speaking parents'
speech to children at five developmental levels ranging from 0;11 to
2;11 in age. Study 2 examines 50 transcripts from the CHILDES
database of Mandarin-speaking caregivers' speech to children ranging
from 1;9 to 2;3 in age. The results suggest that the patterns of
frequency for individual nouns and individual verbs are different, but
that the frequency patterns for nouns and the frequency patterns for
verbs are similar in English and Mandarin. Further, this research
suggests that in both languages the nouns in parents' input are similarly
organized: the most frequent nouns spoken to children tend to name
solid objects that share a similar shape. In contrast verbs' meanings in
both languages tend to include more variable conceptual relations.
Does error-free use of French negation constitute evidence for Very Early Parameter Setting?
Authors: JOSEPH KATE L. , PINE JULIAN M.
Published: July 2002

Many recent generativist models attribute grammatical knowledge to young children on the basis that children's language patterns the same way as the target adult language. It has been proposed that the child acquires this knowledge early on in development by a process of parameter setting. Wexler (1996) presents the VERY EARLY PARAMETER SETTING HYPOTHESIS (VEPS), which suggests that basic language-specific parameters are set correctly at the earliest observable stages, that is, from the onset of multi-word speech. However, the patterns predicted by VEPS are necessarily a characteristic feature of the input language and could therefore be just as readily explained in more limited scope terms. A good example of this is French negation where, in order to perform correctly, the child simply has to register that certain lexical forms precede the negative particle pas and certain other forms follow it. One implication of such a limited scope account is that there should be a strong relation between the lexical specificity of children's and mothers' use of verbs before and after pas. We present data for one subject, aged from 2;1 to 2;8, that are compatible with this hypothesis. While these data do not count directly against VEPS, they do suggest that the very low frequency of errors in children's use of French negation does not in and of itself constitute evidence for early syntactic knowledge.
Why are some verbs learned before other verbs? Effects of input frequency
and
structure on children's early verb use
Authors: NAIGLES LETITIA R. , HOFF-GINSBERG ERIKA
Published: July 2002

This study investigated the extent to which the nature of verb
input
accounts for the order in which children acquire verbs. We assessed the

nature of verb input using a combined sample of the speech of 57
mothers addressing their Stage I children. We assessed the order of verb

acquisition using as our database a combined sample of those children's

speech 10 weeks later and using as our measure of order of acquisition

the frequency of verb occurrence. The first set of analyses established

the validity of this measure of acquisition order by comparing it with

order of acquisition data obtained from checklist and diary data. The
second set of analyses revealed that three properties of the input were

significant predictors of the order of acquisition of the 25 verbs that
were
the focus of this study. The predictive properties of input were the total

frequency, final position frequency, and diversity of syntactic environments

in which the verbs appeared. These findings suggest that the way
verbs appear in input influences their ease of acquisition. More specifically,

the effect of syntactic diversity in input provides support for the
syntactic bootstrapping account of how children use structural information

to learn the meaning of new verbs.
Children's comprehension of unfamiliar regional
accents: a preliminary investigation
Authors: NATHAN LIZ , WELLS BILL , DONLAN CHRIS
Published: July 2002

The effect of regional accent on children's processing of
speech is a
theoretically and practically important aspect of phonological development

that has been little researched. 48 children from London,
aged four and seven years old, were tested on their ability to repeat and

define single words presented in their own accent and in a Glaswegian
accent. Results showed that word comprehension was significantly
reduced in the Glaswegian condition and that four-year-olds performed
less successfully than seven-year-olds. Both groups made similar
numbers of lexical misidentifications, but the younger children were
more likely to fail to access any word at all. On the repetition task,
the
younger children showed a different pattern of errors to the older
children, their productions being apparently more influenced by the
phonetics of the Glaswegian stimuli. It is suggested that such phonetic

responses are related to the younger children's failure to map the

unfamiliar accent onto their own phonological representations. It is
proposed that the lexical misidentifications, common to both age groups,

are more likely to be induced by lack of context. The paper concludes
with discussion of implications of these findings for our understanding

of how children develop the ability to process unfamiliar regional
accents.
Language choice in the earliest utterances: a case
study with methodological implications
Authors: DEUCHAR MARGARET , QUAY SUZANNE
Published: July 2002

In this case study we investigate how early a developing bilingual
exposed simultaneously to English and Spanish can make appropriate
language choices. We propose two methodological requirements for
studies of this kind: (1) detailed records of the development of the
child's lexicon; and (2) data collection in more than one language
context. Our own study relies on detailed records of the child's
cumulative vocabulary from the first word at ten months, and on weekly
audiovideo recordings in both English and Spanish contexts from age
1;3. Analysis of the data shows a strong tendency for the language of the
child's utterances to match that of the context at ages 1;7–1;8.
Box and packing dimensions of projections and dimension profiles
Authors: HOWROYD J. D.
Published: July 2002

For E a subset of ℝn and s ∈ [0, n]
we define upper and lower box dimension profiles, B-dimsE and
B-dimsE respectively, that are closely related to the box
dimensions of the orthogonal projections of E onto subspaces of ℝn. In particular,
the projection of E onto almost all m-dimensional subspaces has upper box dimension
B-dimmE and lower box dimension B-dimmE.
By defining a packing type measure with respect to s-dimensional kernels we are able to establish the connection
to an analogous packing dimension theory.
Surgeries on periodic links and homology of periodic 3-manifolds
Authors: PRZYTYCKI JÓZEF H. , SOKOLOV MAXIM V.
Published: July 2002

Fix a prime integer p. We show that a closed orientable 3-manifold M admits an
action of Zp with the fixed point set S1
if and only if M can be obtained as the result of surgery on a p-periodic framed link
L and Zp acts freely on the components
of L. We prove a similar theorem for free Zp-actions.
As an interesting application, we prove the following, rather unexpected result: for any M as above and for any odd prime
p, H1(M, Zp) ≠ Zp.
We also prove a similar criterion of 2-periodicity for rational homology 3-spheres.
Primitive divisors of Lucas and Lehmer sequences, III
Authors: VOUTIER PAUL M.
Published: July 2002

In this paper we prove that if n>30 030, then the
nth element of any Lucas or
Lehmer sequence has a primitive divisor.
Minimal Siegel modular threefolds
Authors: GRITSENKO VALERI , HULEK KLAUS
Published: July 2002

The starting point of this paper is the maximal extension
Γ*t of Γt, the
subgroup of
Sp4(ℚ) which is conjugate to the paramodular group. Correspondingly
we
call the quotient
[Ascr ]*t=Γ*t\ℍ2

the minimal Siegel modular threefold. The space [Ascr ]*t
and the
intermediate spaces between
[Ascr ]t=Γt\ℍ2

which is the space of (1, t)-polarized abelian surfaces and
[Ascr ]*t have not yet been studied in any detail.
Using the
Torelli theorem we first prove that [Ascr ]*t can
be interpreted
as the space of Kummer surfaces of (1, t)-polarized abelian surfaces
and that
a certain degree 2 quotient of [Ascr ]t which lies over

[Ascr ]*t is a moduli space of lattice polarized
K3
surfaces. Using the action of Γ*t on
the
space of Jacobi forms we show that many spaces between [Ascr ]t
and
[Ascr ]*t possess a non-trivial 3-form, i.e. the
Kodaira
dimension of these spaces is non-negative. It seems
a difficult problem to compute the Kodaira dimension of the spaces
[Ascr ]*t themselves.
As a first necessary step in this direction we determine the divisorial
part of the
ramification locus of the finite map
[Ascr ]t→[Ascr ]*t. This
is a
union of Humbert surfaces which can be interpreted as Hilbert modular surfaces.
Genus one 1-bridge positions for the trivial knot and cabled knots
Authors: HAYASHI CHUICHIRO
Published: July 2002

Let (Vi, ti)

be a pair consisting of a solid torus
Vi and an unknotted arc ti
properly
imbedded in Vi for i=1 and 2.
Taking the union of these pairs we obtain a pair
(M, K) of the 3-dimensional sphere or a lens space
M and a knot K. We call such
a knot K a genus one 1-bridge knot. In this paper we determine
when a genus one
1-bridge knot is the trivial knot or a cabled knot.
Signature invariants of links
from irregular covers and non-abelian covers
Authors: CHA JAE CHOON , KO KI HYOUNG
Published: July 2002

Signature invariants of odd dimensional links from irregular covers and non-abelian covers of complements are obtained by using the technique of Casson and
Gordon. We show that the invariants vanish for slice links and can be considered as
invariants under Fm-link concordance. We
illustrate examples of links that are not
slice but behave as slice links for any invariants from abelian covers.