bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal variation of annelids in the intertidal zone of beaches of the São Sebastião Channel, southern Brazil
Authors: Rizzo A.E. , Amaral A.C.Z.
Published: July 2002

Monthly collections were made for one year (August 1995 to July 1996) in the intertidal zone of two beaches (Engenho d'Água and São Francisco) located in the São Sebastião Channel, State of São Paulo, Brazil, in order to establish the seasonal fluctuations of the species and the factors determining these fluctuations. On each beach, a 10 m wide sector of varying width was established, from which 15 samples/month were collected with a cylindrical corer (0·01 m2). The salinity of the interstitial water and the temperature of the sediment were measured monthly, while the granulometric parameters and calcium carbonate and organic matter concentrations were recorded seasonally. The temporal distribution of the species was more homogeneous at Engenho d'Água, where the highest diversity and evenness values were also found, although the number of individuals was lower. At São Francisco, the monthly abundance was higher, but the richness, diversity, and evenness values were lower, showing some heterogeneity in the temporal distribution patterns of the species. Most species at Engenho d'Água reached their peak of abundance in summer and autumn. The most abundant and frequent species at Engenho d'Água were Nematonereis hebes, Cirriformia filigera (summer), Scyphoproctus djiboutiensis (spring), Owenia fusiformis and Isolda pulchella (winter). At São Francisco, the capitellids Capitella capitata, Heteromastus filiformis, and Capitomastus minimus, and the tubificid oligochaetes dominated in the summer, and Laeonereis acuta and Scolelepis squamata in the winter. The log-normal distribution of the species was used to group those species that are sensitive to and those that are tolerant of organic enrichment, over the four seasons of the year.
Patterns of shell utilization and selection in two sympatric hermit crabs (Anomura: Diogenidae) in south-eastern Brazil
Authors: Floeter S.R. , Nalesso R.C. , Rodrigues M.M.P. , Turra A.
Published: July 2002

The present study evaluated shell utilization and preference of two sympatric hermit crab species, Calcinus tibicen and Clibanarius antillensis, from Ilha Galheta de Dentro, Vitória Bay, south-eastern Brazil. Distribution of individuals and use and availability of shells were estimated in the field, where micro-habitat and shell partitioning were demonstrated between the two species of crabs. Calcinus occurred in higher numbers in the infralittoral fringe and shallow subtidal, while Clibanarius was found mainly in the midlittoral zone. The crabs used shells of different architectures and sizes. Calcinus used mainly globose and low spired shells (Tegula viridula and Cymatium parthenopeum), while Clibanarius utilized predominantly the elongated and high spired ones (mainly Cerithium atratum). Clibanarius used shells with smaller volume, weight, and aperture. Free access experiments were conducted in the laboratory and showed that Calcinus and Clibanarius had a high satisfaction rate, i.e. only 50% of the crabs exchanged their shells. From those that exchanged, they chose shells with higher internal volume than that used in the field, while shell weight did not present any increase. Clibanarius was found in shells closer to the preferred ones and in a very different proportion from shell availability, contrasting to Calcinus, which followed shell availability instead of their preferences. Shell internal volume was more important as a choice factor than the weight for both hermit crab species, showing that crabs optimized shell volume in relation to shell weight in the free access experiments.
Effects of incident light and background conditions on potential conspicuousness of Hawaiian coral reef fish
Authors: Barry Karen L. , Hawryshyn Craig W.
Published: July 2002

Many coral reef fish are assumed to be conspicuous in their natural environment due to their bold and distinct colour patterns. However there have been few attempts to quantify the conspicuousness of coral reef fish under natural photic conditions. In this study, the effects of incident light and background conditions on the potential conspicuousness of four species of Hawaiian reef fish (Chaetodon auriga, Labroides phthirophagus, Thalassoma duperrey, Zebrasoma flavescens) were examined. The optical properties of water, coral and fish colour patterns were measured with an underwater spectroradiometer. Potential conspicuousness was quantified by calculating luminance (brightness) contrast and spectral (colour) contrast within fish colour patterns, and between patterns and natural backgrounds, i.e. water and coral. Under different illuminating and background conditions, the contrast from these fishes was highly variable. Different incident light conditions resulted in significant differences in inherent spectral contrast for L. phthirophagus. All fish had significantly different luminance contrast when the optical properties of the water backgrounds varied. Against coral backgrounds, T. duperrey and Z. flavescens had significantly different luminance contrast and L. phthirophagus and T. duperrey had significantly different spectral contrast. These results have important implications for theories on the adaptive significance of reef fish coloration since the conspicuousness of reef fish appears to be highly dependant on local photic conditions and therefore, some colour patterns may not be conspicuous in the wild as is often presumed.
A novel life history strategy of the hydrozoan, Hybocodon prolifer
Authors: Nakayama Akie , Numakunai Takaharu
Published: July 2002

The life history of the hydrozoan, Hybocodon prolifer, was observed. The polyp from the actinula larva forms the stolon soon after metamorphosis. The stolon is dormant during the warm seawater season. The polyp does not produce the medusa. In early winter the stolon starts to form the polyp, and the polyp produces the medusae. Subsequently the polyp forms the stolon. Experimentally the stolon can be induced to form the polyp at any time during aestivation by treatment with low temperature seawater. Neither the polyp from the actinula nor that from the aestivating stolon forms the next polyp. In this case the hydrozoan is solitary. When the polyp forms the stolon with branches, a polyp is formed from each branch after aestivation. In this case the hydrozoan is colonial. If the stolon piece is divided into several pieces, a polyp is formed from each piece. When the contents of the stolon are extruded, the extruded cells form a cellular mass in several hours, and undergo morphogenesis to form a polyp, as does an intact stolon. The stolon is covered by a thick perisarc, and the endodermal cells contain large quantities of yolk-like granules. A few nematoblasts are found dispersed among the endodermal cells.
On ‘A new cosmological argument’
Authors: OPPY GRAHAM
Published: July 2002

Richard Gale and Alexander Pruss contend that their ‘new cosmological
argument’ is an improvement over familiar cosmological arguments because it
relies upon a weaker version of the Principle of Sufficient Reason than that used in
those more familiar arguments. However, I note that their ‘weaker’ version of the
Principle of Sufficient Reason entails the ‘stronger’ version of that principle which is
used in more familiar arguments, so that the alleged advantage of their proof turns
out to be illusory. Moreover, I contend that, even if their argument did rely on a
weaker version of the Principle of Sufficient reason, nontheists would still be
perfectly within their rights to refuse to accept the conclusion of the argument.
Feeling of absolute dependence or absolute feeling
of dependence? (What Schleiermacher really said
and why it matters)
Authors: Behrens Georg
Published: July 2002

Friedrich Schleiermacher is known as the theologian who said that
the
essence of Christian faith is a state of mind called ‘the feeling
of absolute
dependence’. In this respect, Schleiermacher's reputation owes
much to the influential
translation of his dogmatics prepared by Mackintosh, Stewart and others.
I argue
that the translation is misleading precisely as to the terms which Schleiermacher
uses
in order to refer to the religious state of mind. I also show that the
translation
obscures a problem of some substantive depth regarding what Schleiermacher

thought to be the nature of pious feeling.
Good genes, mating effort, and delinquency
Authors: Lalumière Martin L. , Quinsey Vernon L.
Published: July 2002

High mating effort and antisocial and delinquent behaviors are closely linked. Some delinquent behaviors may honestly signal genetic quality. Men who exhibit high mating effort and who have high genetic quality would be expected to engage in more sexual coercion than other men because its costs to them are lowered by female preferences for them as sexual partners.
Threat perceptions and avoidance in recurrent dreams
Authors: Zadra A. , Donderi D. C.
Published: July 2002

Revonsuo argues that the biological function of dreaming is to simulate threatening events and to rehearse threat avoidance behaviors. He views recurrent dreams as an example of this function. We present data and clinical observations suggesting that (1) many types of recurrent dreams do not include threat perceptions; (2) the nature of the threat perceptions that do occur in recurrent dreams are not always realistic; and (3) successful avoidance responses are absent from most recurrent dreams and possibly nightmares.

[Hobson et al.; Revonsuo]
Over the top: Are there exceptions to the basic capacity limit?
Authors: Wilding John
Published: July 2002

Can we identify individuals with a larger basic capacity than Cowan's proposed limit? Thompson et al. (1993) claimed that Rajan Mahadevan had a basic memory span of 13–15 items. Some of their supporting evidence is reconsidered and additional data are presented from study of another memory expert. More detailed analysis of performance in such cases may yield different conclusions.
Primacy of organising effects of testosterone
Authors: Campbell Anne , Muncer Steven , Odber Josie
Published: July 2002

A test of a biosocial model is reported in which we found
no impact of circulating testosterone on either status-seeking or
aggression. The fact that sex differences in competitiveness and
aggression appear in childhood strongly suggests that the major
impact of testosterone is organisational. Whereas dominance and
resources are linked among males, female aggression may be a
function of pure resource competition, with no element of
status-seeking.
Locus equations: A partial solution to the problem of consonant place perception
Authors: Diehl Randy L.
Published: July 2002

In their important work on locus equations, Sussman and his
colleagues have helped to simplify the theoretical problem of how
human listeners identify place of articulation contrasts among
consonants, but much work remains before this problem is
solved.
Neurobiology of extraversion: Pieces of the puzzle still missing
Authors: Isom Jennifer , Heller Wendy
Published: July 2002

The neurobiological mechanisms associated with affiliation,
that Depue & Collins argue are a central component of extraversion
are not specified in their model. In addition, only the involvement of
the prefrontal cortex in extraversion is discussed, although recent
evidence suggests that activity associated with additional cortical
regions may be related to this trait. Finally, the assumption that
neurobiological mechanisms underlie or play a causal, and therefore,
more fundamental role than psychological constructs in the trait is
challenged.
Where Do New Ideas (About Class) Come From?
Authors: Weinstein Barbara
Published: July 2002

In my comment I raise two main questions about the Eley/Nield essay.
First, I express some doubts about whether the issues discussed in their essay
can be unproblematically transposed to historiographical debates in areas beyond
Western Europe and North America. Certain themes, such as the need to
reemphasize the political, are hardly pressing given the continual emphasis on
politics and the state in Latin American labor history. Closely related to this,
I question whether the state of gender studies within labor history can be used,
in the way these authors seem to be doing, as a barometer of the sophistication
and vitality of labor and working-class history. Despite recognizing the
tremendous contribution of gendered approaches to labor history, I express
doubts about its ability to help us rethink the category of class, and even
express some concern that it might occlude careful consideration of class
identities. Instead, pointing to two pathbreaking works in Latin American labor
history, I argue that the types of questions we ask about class, and primarily
about class, can provide the key to innovative scholarship about workers even if
questions such as gender or ethnicity go unexamined. Finally, I point out that
class will only be a vital category of analysis if it is recognized not simply
as “useful,” but as forming a basis for genuinely creative and
innovative historical studies.
‘Believe’? Vocoders, digitalised female identity and camp
Authors: Dickinson Kay
Published: July 2002

In the two or so years since Cher's ‘Believe’ rather unexpectedly became the number one selling British single of 1998, the vocoder effect – which arguably snagged the track such widespread popularity – grew into one of the safest, maybe laziest, means of guaranteeing chart success. Since then, vocoder-wielding tracks such as Eiffel 65's ‘Blue (Da Ba Dee)’ and Sonique's ‘It Feels So Good’ have held fast at the slippery British number one spot for longer than the now-standard one week, despite their artists' relative obscurity. Even chart mainstays such as Madonna (‘Music’), Victoria Beckham (with the help of True Steppers and Dane Bowers) (‘Out of Your Mind’), Steps (‘Summer of Love’) and Kylie Minogue (the back-ups in ‘Spinning Around’) turned to this strange, automated-sounding gimmick which also proved to be a favourite with the poppier UK garage outfits (you can hear it on hits such as Lonyo/Comme Ci Comme Ca's ‘Summer of Love’, for example).
On the optical analysis of the ray path-lengths in the diffraction
of femtosecond XUV and soft X-ray pulses
Authors: VILLORESI P.
Published: July 2002

During the diffraction of a femtosecond pulse with
a grating, apart spectral filtering, there occurs a time
stretching due to the difference in the path length among
the rays diffracted, even of equal wavelength. The reason
resides in the action of the grating: to depart from the
behavior of the mirror, that is, α = β, and to direct
the rays in directions whose paths are groove-by-groove
different of mλ. The compensation of this
broadening is studied in the following by using a pair of
grating in a particular mounting. The configuration is
studied for the application in the selection of one single
laser harmonics in the framework of high order harmonic
generation processes.
The Weston wheelchair mounted assistive robot - the design story
Authors: Hillman Michael , Hagan Karen , Hagan Sean , Jepson Jill , Orpwood Roger
Published: July 2002

Robotic technology can be used in several ways to benefit people with disabilities. This paper describes the mounting of a robotic arm to a powered wheelchair to
assist disabled users in daily activities. Although there are many potential benefits for the disabled user, there are also very strong requirements and compromises, which must be considered in integrating the robotic arm with the wheelchair. This paper focuses on how these integration issues have been addressed.
A capacitance sensor for safeguarding operators of industrial robots
Authors: Karlsson Nils
Published: July 2002

To increase operator safety in robotic working cells, a capacitive sensor for the detection of humans has been developed. The sensor consists of two electrically conducting planes, insulated electrically from the ambient. When the dielectric or conductive conditions
in the space between the planes are altered, e.g. a person enters, the sensor will indicate the presence of the person. The strength of the electric field caused by the sensor is kept low by lock-in amplifier technique. In the article the basic detection principle, the sensor electronics and the sensor signal handling are described and some practical experiments are
presented.
Analysis and Experimentation of Transpose Jacobian-based Cartesian Regulators
Authors: Kelly Rafael , Coello Angel
Published: July 2002

Transpose Jacobian-based controllers represent
an attractive approach to robot control in Cartesian space. These
controllers attempt to drive the robot end-effector posture to a
specified desired position and orientation without solving either the inverse
kinematics nor computing the robot inverse Jacobian. A wide class
of transpose Jacobian-based regulators obtained from the energy shaping plus
damping injection technique is analyzed in this paper. Our main
theoretical contribution is the introduction of a novel analysis which
does not invoke any assumption on Jacobian singularities to ensure
local asymptotic stability for a family of nonredundant robots. The
performance of four transpose Jacobian-based regulators is illustrated via experimental
tests conducted on a direct-drive vertical arm.
A new dynamic formulation for robot manipulators containing closed kinematic
chains
Authors: Xu Xiang-Rong , Chung Won-Jee , Choi Young-Hyu , Ma Xiang-Feng
Published: July 2002

This paper presents a new
recursive algorithm of robot dynamics based on the Kane's dynamic
equations and Newton-Euler formulations. Differing from Kane's work, the algorithm
is general-purpose and can be easily realized on computers. It
is suited not only for robots with all rotary joints
but also for robots with some prismatic joints. Formulations of
the algorithm keep the recurrence characteristics of the Newton-Euler formulations,
but possess stronger physical significance. Unlike the conventional algorithms, such
as the Lagrange and Newton-Euler algorithm, etc., the algorithm can
be used to deal with dynamics of robots containing closed
chains without cutting the closed chains open. In addition, this
paper makes a comparison between the algorithm and those conventional
algorithms from the number of multiplications and additions.
Internal nutrient fluxes in a Puerto Rican rain forest
Authors: McDowell William H.
Published: July 2002

Throughfall and soil solution chemistry were studied for 1 y in a tropical montane forest in the Luquillo Mountains of Puerto Rico. Passage of precipitation through the forest canopy resulted in an increase in the concentration and flux of all solutes except H+ and NO3−. Throughfall chemistry showed no strong seasonal patterns, but concentrations of many solutes declined during weeks of high rainfall. Enrichment in throughfall relative to precipitation was similar to values reported recently for several other tropical sites, with the exception of NH4+, which was particularly high at this site. Based on net throughfall deposition of Cl−, dry deposition of marine aerosols appears to be a relatively minor component (c. 15%) of total deposition. In soil solution, no seasonal patterns in concentration were evident and variability was highest for elements with high biological activity (especially N). Concentrations and fluxes of K+ and dissolved organic carbon (DOC) showed the largest declines as throughfall passed through the soil profile; concentrations of most other elements increased or were relatively constant. Declining DOC flux through the soil profile appears to be due to sorption processes similar to those observed in many temperate forests. Concentrations and fluxes of HCO3− and SiO2 increased substantially in soil solution, but never approached those observed in the stream. This suggests that additional weathering must occur as groundwater moves from this ridgetop site to the stream.
Effects of deforestation on seed banks in a tropical deciduous forest of western Mexico
Authors: Miller P. M.
Published: July 2002

Seed density and seed bank species composition were determined by germination trials on soils collected during the initial phase of deforestation in a Mexican tropical deciduous forest. The reference forest, pre-burn, 1-d post-burn, and 1-y post-burn soils contained 700, 1000, 70 and 3500 germinating seeds m−2, of 30, 30, 8 and 13 species, respectively. A total of 43 dicotyledonous species were identified. Percentages of herbs, vines, shrubs and small trees/shrubs were similar in reference forest, pre-burn, and 1-d post-burn soils; herbs were the most common growth form. Pasture conversion greatly altered seed bank species composition; 81% of the species that germinated from the seed bank before burning were absent from the seed bank 1 d after the fires. One-year post-burn soil was dominated by monocots; only 3% of the seedlings were herbs; no vines, small trees/shrubs or trees germinated. The reference forest and the pre-burn soils had 18 dicot species in common and the highest similarity index, 0.43; six of the shared species were herbs. One-day and 1-y post-burn soils had the lowest similarity index, 0.05. Burning the slashed forest and conversion to cattle pasture depleted the original seed bank, replacing it by one dominated by pasture grasses.
Agent based process management: applying intelligent agents to workflow
Authors: O'BRIEN P. D. , WIEGAND M. E.
Published: July 2002

This paper presents an Agent-based Process Management System (APMS) architecture that combines recent developments in autonomous agent technology and distributed computing platforms. It argues that a service-oriented view is required in order to meet the requirements of open distributed enterprises, now and in the future. This approach embraces and fully supports the decentralisation of responsibility and local autonomy, within and across enterprises. The paper begins by summarising existing approaches to workflow. It describes the APMS approach which extends workflow with the abilities to anticipate process requirements, to resource processes dynamically, and to adapt to exceptions. An important feature of APMS is the absence of a centralised business process representation. Finally, the paper describes an implementation of the APMS architecture, and discusses the engineering issues related to realising such a system within a large organisation.
TRANSIENT ANALYSIS OF PERMANENT CUSTOMERS IN A SINGLE-SERVER
QUEUE WITH MIXED TRAFFIC
Authors: Kobza John E. , Nachlas Joel A.
Published: July 2002

Single-server queueing systems with mixed traffic are
a flexible modeling tool that have been used to analyze
polling systems and database striping strategies. They
also have applications in manufacturing and telecommunication
systems. Ordinary (open) customers arrive according to
a Poisson process, receive service, and leave the system.
Permanent (closed) customers remain in the system, reentering
the queue after receiving service. This work examines the
transient behavior of the permanent customers. The cycle
times and output/departure process for the permanent customers
are described.
Magnetic Discrimination Learning in Rainbow Trout (Oncorhynchus
mykiss)
Authors: Haugh Cordula V. , Walker Michael M.
Published: July 2002

Although conditioning techniques are the most powerful way to
study behavioural responses
by animals to external stimuli, the magnetic sense has proved surprisingly
resistant to
conditioning approaches. This study demonstrated learned discrimination
of magnetic field
intensity stimuli by a new species, the rainbow trout
(Oncorhynchus mykiss). In a unitary
conditioned discrimination technique, four juvenile rainbow trout were
trained to strike a
target at the end of a response bar in anticipation of food.
In successive experiments, the trout
failed to discriminate the presence and absence of a vibration stimulus,
but subsequently
learned to discriminate the presence and absence of a magnetic field intensity
anomaly (peak
intensity of 75 μTesla). The authors conclude that the necessary
conditions for training animals
to magnetic intensity are the use of spatially distinctive stimuli
and of a conditioned response that requires movement.
SPIDA: Abstracting and generalizing layout design cases
Authors: MANFAAT D. , DUFFY A.H.B. , LEE B.S.
Published: July 2002

Abstraction and generalization of layout design
cases generate new knowledge that is more widely applicable
to use than specific design cases. The abstraction and
generalization of design cases into hierarchical levels
of abstractions provide the designer with the flexibility
to apply any level of abstract and generalized knowledge
for a new layout design problem. Existing case-based layout
learning (CBLL) systems abstract and generalize cases into
single levels of abstractions, but not into a hierarchy.
In this paper, we propose a new approach, termed customized
viewpoint—spatial (CV–S), which supports
the generalization and abstraction of spatial layouts into
hierarchies along with a supporting system, SPIDA (SPatial
Intelligent Design Assistant).
The role of competition and habitat in structuring small mammal communities in a tropical montane ecosystem in southern India
Authors: Shanker Kartik
Published: July 2002

Small mammals were sampled in two natural habitats (montane stunted evergreen forests and montane grassland) and four anthropogenic habitats (tea, wattle, bluegum and pine plantation) in the Upper Nilgiris in southern India. Of the species trapped, eight were in montane evergreen forests and three were in other habitats. Habitat discrimination was studied in the rodents Rattus rattus and Mus famulus and the shrew Suncus montanus in the montane forest habitat. Multivariate tests on five variables (canopy cover, midstorey density, ground cover, tree density, canopy height) showed that R. rattus uses areas of higher tree density and lower canopy cover. Suncus montanus and M. famulus use habitat with higher tree density and ground cover and lower canopy height. Multivariate tests did not discriminate habitat use between the species. Univariate tests, however, showed that M. famulus uses areas of higher tree density than R. rattus and S. montanus. Rattus rattus was the dominant species in the montane forest, comprising 60.9+ of total density, while the rodent Millardia meltada was the dominant species in the grassland. Studies of spatial interaction between these two species in habitats where they coexisted showed neither overlap nor avoidance between the species. Rattus rattus, however, did use areas of lower ground cover than did M. meltada. The analysis of spatial interactions between the species, habitat discrimination and use, and the removal experiments suggest that interspecific competition may not be a strong force in structuring these small mammal communities. There are distinct patterns in the use of different habitats by some species, but microhabitat selection and segregation is weak. Other factors such as intraspecific competition may play a more important role in these communities.
RAPD and isoenzyme analysis of genetic variability in three allied species of catfish (Siluriformes: Pimelodidae) from the Tibagi River, Brazil
Authors: de Almeida Fernanda Simões , Fungaro Maria Helena Pelegrinelli , Sodré Leda Maria Koelblinger
Published: July 2002

Genetic variability in three species of Pimelodidae catfish (Iheringichthys labrosus, Pimelodus maculatus and Pimelodus cf. absconditus), collected at four sites in the Tibagi river‐basin: Sertaneja, Londrina (lower Tibagi), Sapopema (middle Tibagi) and Tibagi (upper Tibagi) was analysed using RAPD and isoenzymatic techniques. Iheringichthys labrosus had the greatest genetic variability showing a proportion of mean polymorphic loci (P̄m) of 53.7+. The dendrogram showed that the individuals from the locations were clustered together, supporting the hypothesis that I. labrosus has a sedentary or localized geographical distribution. Pimelodus maculatus is the only species studied that is considered to be highly migratory. The P̄m obtained for this species was 30.2+. Their genetic dendrogram showed that the individuals were not clustered, based on the place of collection. P. cf. absconditus had a P̄m value of 47.4+, and the external morphology of this species is similar to that of I. labrosus, which hindered differentiation of individuals from the two species. RAPD and isoenzyme analysis, however, provided differential patterns for P. cf. absconditus from I. labrosus.
Effects of radio‐collars on European badgers (Meles meles)
Authors: Tuyttens F. A. M. , Macdonald D. W. , Roddam A. W.
Published: July 2002

The relationships between radio‐collaring/tracking and 12 biometric parameters in a population of badgers (Meles meles) that were live‐trapped in south‐west England were investigated. The length of time for which a badger had worn a radio‐collar was selected as an explanatory variable in generalized linear models of three biometric parameters (body condition, body weight and testes volume) irrespective of whether or not age class was included as a variable in the analyses. There was evidence that badgers that had been carrying a radio‐collar for 1–100 days had lower body condition scores both when compared to badgers that had not been collared and with those that had been collared for longer than 100 days, suggesting a post‐collaring acclimation period. In addition, the time period between first and last capture was longer for radio‐collared than non‐collared badgers. It is unlikely that this was due to an effect of collaring on trappability or to non‐random selection of badgers for collaring. Although testes size differed between non‐collared badgers and badgers that had been tagged for > 100 days, the relationship between radio‐collaring and reproductive output remained unproven. These results highlight not only the need to assess the welfare aspects of radio‐collaring but also the potential intricacy of corollaries of collaring. Explorations such as that reported here are important to the validity of studies that make use of radio‐telemetry.
Working with family carers: towards a partnership approach
Authors: Nolan Michael
Published: July 2002

The use of the term ‘family (informal) carer’, as it is currently conceptualized, is recent and is largely the product of increased attention in the academic and policy literature over the last two decades. Despite their fairly late arrival on the scene, family carers now occupy centre stage in UK government policy, having being described by the Prime Minister, Tony Blair, as the ‘unsung heroes’ of British life, who are essential to the fabric and character of Britain. Such recognition stems from the growing realization that family carers are the lynchpin of community care, providing 80% of all the care needed at an estimated saving to the UK government of some £40 billion annually.
Virtual worlds, real knowledge: towards a hermeneutics of virtuality
Authors: AARSETH ESPEN
Published: July 2002

What is the ‘virtual’ and what types of phenomena can be so described? This article tries to establish the context within which this unclear and ideological term can be constructive. Phrases such as ‘virtual community’ are paradoxical and weak, but ‘virtual’ applied cognitively to simulated phenomena, such as virtual worlds or computer games, has validity and represents an alternative discourse mode to narratives and storytelling in conveying experience and knowledge.
Differential association of HIV-related neuropsychological
impairment with semantic versus repetition priming
Authors: JASIUKAITIS PAUL , FEIN GEORGE
Published: July 2002

There is evidence that the facilitating effects
of stimulus repetition (repetition or identity priming)
are mediated by visuoperceptual functions local to extrastriate
cortex. Semantic or verbal–associative priming, on
the other hand, is believed to be a function of more anterior
brain systems. The present study finds evidence for disrupted
semantic priming with intact repetition priming in a cognitively
impaired HIV+ sample. These results are consistent with
recent brain-imaging evidence for a subcortical and white-matter
locus for HIV associated neuropathology resulting in effects
on subcortical–frontal systems. (JINS, 1999,
5, 434–441.)
A MutaSynth in parameter space: interactive composition through evolution
Authors: Dahlstedt Palle
Published: July 2002

In this vision paper I will discuss a few questions concerning the use of generative processes in composition and automatic music creation. Why do I do it, and does it really work? I discuss the problems involved, focusing on the use of interactivity, and describe the use of interactive evolution as a way of introducing interactivity in composition. The installation MutaSynth is presented as an implementation of this idea.
Plant 21D7 Protein, a Nuclear Antigen Associated with Cell Division, Is a Component of the 26S Proteasome
Authors: Smith M. W. , Ito M. , Miyawaki M. , Sato S. , Yoshikawa Y. , Wada S. , Maki H. , Nakagawa H. , Komamine A.
Published: July 2002

Previously, we cloned a carrot (Daucus carota L.) cDNA encoding a 45-kD protein, 21D7, located in the nuclei of proliferating cells. The 21D7 protein is similar to the partial sequence of a regulatory subunit of the bovine 26S proteasome, p58 (G. DeMartino, C.R. Moomaw, O.P. Zagnitko, R.J. Proske, M. Chu-Ping, S.J. Afendis, J.C. Swaffield, C.A. Slaughter [1994] J Biol Chem 269: 20878–20884) and to the deduced sequence encoded by the Saccharomyces cerevisiae gene SUN2 (M. Kawamura, K. Kominami, J. Takeuchi, A. Toh-e [1996] Mol Gen Genet 251: [146–152]). In our work, the expression of plant 21D7 cDNA rescued the yeast sun2 mutant. Fractionation of carrot and spinach (Spinacia oleracea L.) crude extracts showed that the 21D7 protein sedimented with the active 26S proteasomes. The cessation of cell proliferation in carrot suspensions at the stationary phase caused 26S proteasome dissociation and, correspondingly, the 21D7 protein sedimented together with the free regulatory complexes of the 26S proteasomes. Large-scale purification of carrot 26S proteasomes resulted in coisolation of the 21D7 protein. Polyacrylamide gel electrophoresis under nondenaturing conditions showed that the 21D7 protein had the same mobility as the 26S proteasome and that proteasome dissociation changed the mobility of the 21D7 protein accordingly. We conclude that the 21D7 protein is a subunit of the plant 26S proteasome and that it probably belongs to the proteasome regulatory complex.
Calcium-Regulated Proteolysis of eEF1A
Authors: Ransom-Hodgkins Wendy D. , Brglez Irena , Wang Xuemin , Boss Wendy F.
Published: July 2002

Eukaryotic elongation factor 1α (eEF1A) can be post-translationally modified by the addition of phosphorylglycerylethanolamine (PGE). [14C]Ethanolamine was incorporated into the PGE modification, and with carrot (Daucus carota L.) suspension culture cells, eEF1A was the only protein that incorporated detectable quantities of [14C]ethanolamine (Ransom et al., 1998). When 1 mm CaCl2 was added to microsomes containing [14C]ethanolamine-labeled eEF1A ([14C]et-eEF1A), there was a 60% decrease in the amount of [14C]et-eEF1A recovered after 10 min. The loss of endogenous [14C]et-eEF1A was prevented by adding EGTA. Recombinant eEF1A, which did not contain the PGE modification, also was degraded by microsomes in a Ca2+-regulated manner, indicating that PGE modification was not necessary for proteolysis; however, it enabled us to quantify enodgenous eEF1A. By monitoring [14C]et-eEF1A, we found that treatment with phospholipase D or C, but not phospholipase A2, resulted in a decrease in [14C]et-eEF1A from carrot microsomes. The fact that there was no loss of [14C]et-eEF1A with phospholipase A2 treatment even in the presence of 1 mmCa2+ suggested that the loss of membrane lipids was not essential for eEF1A proteolysis and that lysolipids or fatty acids decreased proteolysis. At micromolar Ca2+ concentrations, proteolysis of eEF1A was pH sensitive. When 1 μmCaCl2 was added at pH 7.2, 35% of [14C]et-eEF1A was lost; while at pH 6.8, 10 μm CaCl2 was required to give a similar loss of protein. These data suggest that eEF1A may be an important downstream target for Ca2+ and lipid-mediated signal transduction cascades.
Crop Biotechnology. Where Now?
Authors: Miflin Ben J.
Published: July 2002

Nature Biotechnology organized a conference in London on Agbiotech 99: Biotechnology and World Agriculture (November 14–16, 1999). The conference focused entirely on crop biotechnology and covered both societal and scientific aspects. Below is an account of the more important issues raised by the speakers and the audience.
Complementary Expression of Two Plastid-Localized ς-Like Factors in Maize
Authors: Lahiri Sushmita D. , Allison Lori A.
Published: July 2002

The eubacterial-like RNA polymerase of plastids is composed of organelle-encoded core subunits and nuclear-encoded ς-factors. Families of ς-like factors (SLFs) have been identified in several plants, including maize (Zea mays) and Arabidopsis. In vitro import assays determined that at least two of the maize ς-like proteins have functional chloroplast transit peptides and thus are likely candidates for chloroplast transcriptional regulators. However, the roles of individual SLFs in chloroplast transcription remain to be determined. We have raised antibodies against the unique amino-terminal domains of two maize SLFs, ZmSig1 and ZmSig3, and have used these specific probes to examine the accumulation of each protein in different maize tissues and during chloroplast development. The expression of ZmSig1 is tissue specific and parallels the light-activated chloroplast development program in maize seedling leaves. Its accumulation in mature chloroplasts however, is not affected by subsequent changes in the light regime. It is interesting that the expression profile of ZmSig3 is complementary to that of ZmSig1. It accumulates in non-green tissues, including roots, etiolated seedling leaves, and the basal region of greening seedling leaves. The nonoverlapping expression patterns of these two plastid-localized SLFs suggest that they may direct differential expression of plastid genes during chloroplast development.
Analysis of the Ethylene Response in theepinastic Mutant of Tomato
Authors: Barry Cornelius S. , Fox Elizabeth A. , Yen Hsiao-ching , Lee Sanghyeob , Ying Tie-jin , Grierson Donald , Giovannoni James J.
Published: July 2002

Ethylene can alter plant morphology due to its effect on cell expansion. The most widely documented example of ethylene-mediated cell expansion is promotion of the “triple response” of seedlings grown in the dark in ethylene. Roots and hypocotyls become shorter and thickened compared with controls due to a reorientation of cell expansion, and curvature of the apical hook is more pronounced. Theepinastic (epi) mutant of tomato (Lycopersicon esculentum) has a dark-grown seedling phenotype similar to the triple response even in the absence of ethylene. In addition, in adult plants both the leaves and the petioles display epinastic curvature and there is constitutive expression of an ethylene-inducible chitinase gene. However, petal senescence and abscission and fruit ripening are all normal in epi. A double mutant (epi/epi;Nr/Nr) homozygous for both the recessive epi and dominant ethylene-insensitive Never-ripe loci has the same dark-grown seedling and vegetative phenotypes as epi but possesses the senescence and ripening characteristics ofNever-ripe. These data suggest that a subset of ethylene responses controlling vegetative growth and development may be constitutively activated in epi. In addition, theepi locus has been placed on the tomato RFLP map on the long arm of chromosome 4 and does not demonstrate linkage to reported tomato CTR1 homologs.
A software system for rigid-body modelling of solution scattering data
Authors: Kozin M.B. , Svergun D.I.
Published: July 2002

A computer system for rigid body modelling against solution scattering data is described. Fast algorithms to compute scattering from a complex of two arbitrary positioned subunits are implemented and coupled with the graphics program ASSA (Kozin, Volkov & Svergun, 1997, J. Appl. Cryst.
30, 811-815). Mutual positions and orientations of the subunits (represented by low-resolution envelopes or by atomic models) can be determined by interactively fitting the experimental scattering curve from the complex. The system runs on the major Unix platforms (SUN, SGI and DEC workstations).
Powder diffraction beyond the Bragg law: study of palladium nanocrystals
Authors: Kaszkur Zbigniew
Published: July 2002

An experimental method of measurement of the subtle changes of structure of metal nanocrystals occurring on chemisorption of oxygen, interaction with inert gas and hydrogen,etc., is proposed. The measured patterns and their evolution are interpretedviaatomistic simulations. Described are quantitative observations of the changes in peak position, intensity and half width of the 111 diffraction peak of a palladium catalyst caused by modifying the gaseous environment. The results of the measurements are in line with an atomistic model proposed earlier and prove that the measured average lattice constant of palladium clusters evolves according to their surface relaxation. The evolution of the measured peak intensity suggests surface ordering effects and was used to propose a detailed structural model of nanocrystalline metal particles. The transition of palladium into β-Pd-H in hydrogen under normal conditions was used as a structure probe and provided evidence for the presence of icosahedral clusters in a highly dispersed catalyst. The icosahedral phase is not significantly modified under hydrogen atmosphere and does not transform into the β hydride.
Electric-field-induced structural changes measured with a CCD-coupled X-ray image intensifier
Authors: van Reeuwijk S. J. , Vonk V. , Puig-Molina A. , Graafsma H.
Published: July 2002

The conventional method to measure small induced changes in integrated intensity utilizes a zero-dimensional detector, which greatly limits the data collection speed. This paper shows that the use of an area detector in combination with an X-ray chopper decreases the data collection time significantly. A monochromatic diffraction setup using a charge-coupled device (CCD) detector coupled to an X-ray image intensifier was constructed and tested. The setup proved to be sufficiently stable to measure changes in integrated intensity well below 0.1%. Subsequently, a data set of a piezoelectric KD2PO4crystal in an external electric field was collected. The data were merged to yield 77 unique reflections. The induced structural changes were determined by a least-squares refinement. The results agree very well with experiments in which a zero-dimensional detector was used. The major improvement is the decrease in data collection time by one order of magnitude, without any degradation of the data quality, offering new possibilities for this type of perturbation study.
SAS from inhomogeneous particles with more than one domain of scattering density and arbitrary shape
Authors: Spinozzi F. , Carsughi F. , Mariani P. , Teixeira C.V. , Amaral L. Q.
Published: July 2002

The Small Angle Scattering from inhomogeneous particles is very important in the investigation of biological systems, where the scattering objects might be formed by many domains. For these systems, the scattering intensity, as well as its Fourier transform, are written as a sum of different contributions. In this work, for the simple case of two domains, the form factors of different scattering particle shapes, such as the oblate, prolate and biaxial ellipsoids, spherocylinder and disks were calculated by using a Monte Carlo method. Finally, SAS data of sodium lauryl sulfate micelles in water were analysed by using a model that accounts for polydispersity and micelles of different shape.
X-ray studies on aqueous dispersions of dipalmitoyl phosphotidylglycerol in the presence of salt
Authors: Degovics G. , Latal A. , Lohner K.
Published: July 2002

The structure and lamellarity of lipid vesicles composed of dipalmitoyl phosphatidylglycerol in the presence of salt has been studied by small- and wide-angle X-ray diffraction which revealed formation of unilamellar vesicles up to 150 mM NaCl. Analysis of these data indicated that both the bilayer thickness and the distance of the phosphate groups between the two opposite lipid leaflets increased only by a small amount in the presence of salt. Further addition of NaCl did not markedly affect the wide-angle reflections. However, in the small-angle region additional reflections were observed above 300 mM NaCl, originating from the bilayer stacking in multilamellar vesicles. These observations can be explained by the screening of the negatively charged vesicle surface by Na-ions, thereby reducing the electrostatic repulsion between the lipid bilayers and enabling the formation of multilamellar vesicles.
Direct determination of microstructural parameters from the X-ray diffraction profile of a crystal with stacking faults
Authors: Estevez-Rams Ernesto , Penton-Madrigal Arbelio , Lora-Serrano Raymundo , Martinez-Garcia Jorge
Published: July 2002

The practical aspects of a recently deduced formalism for the direct solution of the powder diffraction pattern of a layer crystal are addressed. It is shown that the obtained solution is particularly well suited to combination with a deconvolution procedure based on a series development of the peak profile. The influence of noise and step size on the obtained solution is discussed. Computer simulation is used to assess the robustness of the proposed procedure. The developed procedure is applied to a powder sample of Y2Co17that is affected by planar disorder.
Scattering curve and radius of gyration of a straight chain of identical spheres
Authors: Kawaguchi Takeshi
Published: July 2002

The angularly averaged scattering intensity and the radius of gyration of a straight chain ofNequal spheres have been derived. The intensity becomes equal to zero at the same points where the intensity of the constituting sphere vanishes. The property holds also for a `particle' formed ofNequally sized and non-overlapping spheres with different electron densities. The radius of the spheres can be determined from the positions of the zeros. The number of the spheres can be obtained from the extrapolated zero-angle intensity or from the radius of gyration in the case of linear chains.
Controllable variation of the intensity of diffracted X-ray beams and double modulation of such beams for transmission and reception of audio information
Authors: Navasardyan M. A.
Published: July 2002

This paper discusses research devoted to the study of the intensity change of diffracted and transmitted X-ray beams under the action of a temperature gradient or acoustic oscillations, as well as the techniques for `controllable complete reflection' of transmitted X-radiation in the direction of the diffracted beam. Also discussed are results on the double modulation of X-ray beam intensity by acoustic oscillations. A scheme is presented for a practical device for transmission and reception of audio information, in particular speech, with the help of X-ray beams diffracted by perfect single crystals. Finally, there are suggestions for applications of modulated beams in the solution of various problems in physics.