bluuebunny/crossref_metadata_2025 huggingface dataset:
Ergodic fractal measures and dimension conservation
Authors: FURSTENBERG HILLEL
Published: April 2008

A linear map from one Euclidean space to another may map a compact set bijectively to a set of smaller Hausdorff dimension. For ‘homogeneous’ fractals (to be defined), there is a phenomenon of ‘dimension conservation’. In proving this we shall introduce dynamical systems whose states represent compactly supported measures in which progression in time corresponds to progressively increasing magnification. Application of the ergodic theorem will show that, generically, dimension conservation is valid. This ‘almost everywhere’ result implies a non-probabilistic statement for homogeneous fractals.
Two facts concerning the transformations which satisfy the weak Pinsker property
Authors: THOUVENOT J.-P.
Published: April 2008

We show that every ergodic, finite entropy transformation which satisfies the weak Pinsker property possesses a finite generator whose two-sided tail field is exactly the Pinsker algebra. This is proved by exhibiting a generator endowed with a block structure quite analogous to the one appearing in the construction of the Ornstein–Shields examples of non Bernoulli K-automorphisms. We also show that, given two transformations T1 and T2 in the previous class (i.e. satisfying the weak Pinsker property), and a Bernoulli shift B, if T1×B is isomorphic to T2×B, then T1 is isomorphic to T2. That is, one can ‘factor out’ Bernoulli shifts.
The Code of Protest: Images of Peace in the West German Peace Movements, 1945–1990
Authors: ZIEMANN BENJAMIN
Published: April 2008

The article examines posters produced by the peace movements in the Federal Republic of Germany during the Cold War, with an analytical focus on the transformation of the iconography of peace in modernity. Was it possible to develop an independent, positive depiction of peace in the context of protests for peace and disarmament? Despite its name, the pictorial self-representation of the campaign ‘Fight against Nuclear Death’ in the late 1950s did not draw on the theme of pending nuclear mass death. The large-scale protest movement in the 1980s against NATO's 1979 ‘double-track’ decision contrasted female peacefulness with masculine aggression in an emotionally charged pictorial symbolism. At the same time this symbolism marked a break with the pacifist iconographic tradition that had focused on the victims of war. Instead, the movement presented itself with images of demonstrating crowds, as an anticipation of its peaceful ends. Drawing on the concept of asymmetrical communicative ‘codes’ that has been developed in sociological systems theory, the article argues that the iconography of peace in peace movement posters could not develop a genuinely positive vision of peace, since the code of protest can articulate the designation value ‘peace’ only in conjunction with the rejection value ‘war’.
Legal nutritional supplements during a sporting event
Authors: Nicholas Ceri
Published: April 2008

Nutrition significantly influences sports performance; however, the efficacy of any nutritional supplement or strategy should be carefully considered in relation to the event and the sex, training and nutritional status of the participant. The causes of fatigue, mechanism of action, safety and legality of the supplement, together with the scientific evidence from studies with an appropriate experimental design, should all be taken into account before incorporating into the training and/or competition diet. The efficacy of ingesting nutritional supplements immediately before and/or during endurance exercise (duration 45–180 min) is reviewed in this chapter. The ingestion of CES (carbohydrate-electrolyte solutions) have been shown to improve both exercise capacity and performance, either due to the maintenance of euglycaemia throughout exercise or the sparing of muscle glycogen early on in exercise. The addition of caffeine to CES may improve endurance performance as a consequence of a reduced perception of effort. Research suggests that the addition of protein to CES may only be effective when a suboptimal amount of CHO (carbohydrate) is ingested during exercise (<60 g of CHO⋅h−1); however, recovery of performance may be enhanced due to a reduction in subsequent muscle soreness and the promotion of muscle protein synthesis after exercise. The findings from studies investigating the effects of ingesting MCTs (medium-chain triacylglycerols) and BCAAs (branched-chain amino acids), either on their own or in combination with CES, on endurance performance have been equivocal and therefore would not be recommended. Any nutritional strategy should be practised in training before being used during a competition.
Improving muscle mass: response of muscle metabolism to exercise, nutrition and anabolic agents
Authors: Tipton Kevin D. , Ferrando Arny A.
Published: April 2008

Muscle mass is critical for athletic performance and, perhaps more importantly for most, health and survival. The metabolic basis for a change in muscle mass is an increase in net muscle protein balance (termed NBAL). NBAL is the difference between MPS (muscle protein synthesis) and MPB (muscle protein breakdown). Thus an increase in MPS and/or a decrease in MPB are necessary for NBAL to increase, leading to accretion of muscle proteins. In particular, accretion of myofibrillar proteins is necessary. NBAL responds to exercise, feeding and other factors. In healthy, weight-stable adults, muscle mass remains constant because periods of positive balance following feeding are countered by periods of negative balance during fasting. A combination of resistance exercise and nutrition is a potent anabolic stimulus through stimulation of MPS from amino acids and attenuation of MPB by carbohydrates. Increased muscle mass results from the accumulation of small amounts of protein in response to each bout of exercise combined with nutrient intake. The magnitude of the response may be influenced by factors other than just the amount of a nutrient ingested. Timing of ingestion, co-ingestion of nutrients and the type of protein may all influence protein accretion. Testosterone is a potent anabolic stimulus primarily through improvement in re-utilization of amino acids from MPB. There is a general lack of efficacy in studies assessing the potential for growth hormone, androstenedione and dehydroepiandrostenedione to increase muscle mass. Creatine supplementation is clearly an effective means to increase muscle mass, especially in combination with resistance exercise, however the mechanisms remain unclear. Results from acute metabolic studies provide useful information for estimation of the efficacy of anabolic agents.
Mechanical resonance of clamped silicon nanowires measured by optical interferometry
Authors: Belov M. , Quitoriano N. J. , Sharma S. , Hiebert W. K. , Kamins T. I. , Evoy S.
Published: April 2008

The mechanical resonance of laterally grown silicon nanowires measured by an optical interferometric technique is reported. The lengths and diameters of the nanowires ranged from L=2to20μm and D=39to400nm, respectively. The wires showed resonant frequencies in the f0=1–12MHz range and resonant quality factors Q at low pressure ranging from Q=5000 to Q=25000. The dependence of resonant frequency on the ratio of diameter to length squared, D∕L2, yielded a ratio of E∕ρ=9400±450m∕s. Assuming a density of ρ=2330kg∕m3, this experimental result yields an experimental Young modulus of E=205±10GPa, consistent with that of a bulk silicon. As the wires were cooled from T=270KtoT=77K, a 0.35% increase of resonant frequency was observed. This increase of resonant frequency with cooling resulted from a change in Young’s modulus and from the thermal contraction of silicon. The quality factor did not vary significantly from P=10−4to102Torr, suggesting that viscous damping does not dominate the dissipative processes in this pressure range. Although viscous damping became important above P=102Torr, relatively high quality factors of Q=7000 were still observed at atmospheric pressure.
Spin coating of a colloidal suspension
Authors: Zhao Y. , Marshall J. S.
Published: April 2008

A discrete-element approach is employed to model the transport, collision, adhesion, and deposition of small colloidal particles in a spin coating process. The computations are used to predict particle distribution and wall adhesion during the nonevaporative phase of spin coating of a thin film, which is important for controlling the abrasiveness, opacity, conductivity, and other properties of the film, as well as for using the deposited particles for growing new materials (e.g., nanotubes). The computations examine the particle distribution and the effect of particle adhesive force on particle deposition during spin coating. Particles are observed to preferentially collect within the film ridge just behind the moving contact line. An increase in the particle adhesive force is observed to lead to enhanced deposition of particles within an inner radius of the film and increase in the aggregate size.
Analysis of Schottky barriers to ultrathin strained Si
Authors: Connelly Daniel , Clifton Paul
Published: April 2008

We evaluated the Schottky barrier height between a metal and strained ultrathin silicon using a simple thermionic emission model combined with a self-consistent solution of Schrödinger’s and Poisson’s equations near the metal/semiconductor interface. Three “Fermi level pinning” models and two published deformation potential parameter sets yielded different results. We show that both strain and silicon thickness substantially affect the Schottky barrier height, although whether the height was increased or decreased depended on the model for Fermi level pinning at the metal/semiconductor interface.
Nondestructive dislocation delineation using topographically enhanced imaging of surface morphologies in 4H-SiC epitaxial layers
Authors: Picard Yoosuf N. , Liu Kendrick X. , Stahlbush Robert E. , Twigg Mark E. , Zhang Xuan , Skowronski Marek
Published: April 2008

The morphology of surface features generated by dislocations present at 4H-SiC epitaxial layer surfaces was investigated by forescattered electron detection (FED) inside a conventional scanning electron microscope. Various growth pit morphologies were correlated to dislocation types using molten KOH etching. Specifically, sharp-apex pits and stripe-shaped pits were consistently linked to screw and edge dislocations, respectively. The size and depth of these growth pits were measured by atomic force microscopy (AFM). Tail-like features were observed by FED emanating from sharp-apex pits and verified by Nomarski optical microscopy (NOM). A mechanism is proposed to explain the FED contrast exhibited by these tail-like features. This mechanism relates the nature of step-flow and spiral growth in the wake of a screw dislocation to the surface distortions resulting in such tail-like features. The Burgers vector direction can thus be determined based on a purely morphological analysis of these tail-like features. The results of this study illustrate the various capabilities of FED for surface imaging as compared to AFM and NOM. The potential for utilizing FED to map dislocation-associated growth pits is discussed.
Transport properties of nanoscale Nb and NbN Josephson junctions fabricated by focused-ion-beam milling
Authors: Matsuba Kazuaki , Watanabe Michio , Tsai Jaw-Shen
Published: April 2008

We have studied low-temperature electrical transport properties of nanoscale Nb∕(Al–)Al2O3∕Nb and NbN∕AlN∕NbN Josephson junctions (JJs) fabricated by focused-ion-beam (FIB) milling. This FIB fabrication process yields high-quality JJs whose superconducting gap energy agrees with the bulk value. In this paper, we report the improvement in the precision of the fabrication technology by employing a weaker ion beam current and by introducing a step of XeF2-gas-assisted milling, which allowed us to reduce the anodization voltage. For Nb JJs, we measured the current-voltage (I-V) characteristics of single-electron transistors (SETs) and examined the current observed within the superconducting energy gap. At finite voltages, we observed current peaks due to the Josephson-quasiparticle (JQP) cycle. Based on the JQP-peak positions, we estimated the charging energy Ec of the SETs. For all SETs, Ec∕kB is larger than 1K, which is consistent with 0.1×0.1μm2 junctions. We also analyzed the superconducting critical current at zero voltage. The ratio Ic∕Ic0 depended on the junction size, where Ic is the measured critical current and Ic0 is the theoretical one. The I-V curves of NbN single Josephson junctions also depended on the junction size, and they were qualitatively different, especially around the energy gap. We will discuss the possible origins for the junction-size dependence.
Temperature dependence of domain-wall depinning fields in constricted Permalloy nanowires
Authors: Lendecke Peter , Eiselt René , Meier Guido , Merkt Ulrich
Published: April 2008

We use ballistic Hall micromagnetometry to determine depinning fields of domain walls (DWs) in Permalloy nanowires in the temperature range between 5 and 50K. The walls are pinned in constrictions defined by a triangularly shaped notch on one side of the wire. The high sensitivity of the Hall sensor to local stray fields allows the detection of individual DWs and a distinction of different wall types. A strong temperature dependence of the depinning fields is observed that can be described by a model with a single energy barrier. For temperatures above 20K, additional types of DWs occur.
CW lasing of current injection blue GaN-based vertical cavity surface emitting laser
Authors: Lu Tien-Chang , Kao Chih-Chiang , Kuo Hao-Chung , Huang Gen-Sheng , Wang Shing-Chung
Published: April 2008

Here, we report the cw laser operation of electrically pumped GaN-based vertical cavity surface emitting laser (VCSEL). The GaN-based VCSEL has a ten-pair InGaN∕GaN multiple quantum well active layer embedded in a GaN hybrid microcavity of 5λ optical thickness with two high reflectivity mirrors provided by an epitaxially grown AlN∕GaN distributed Bragg reflector (DBR) and a Ta2O5∕SiO2 dielectric DBR. cw laser action was achieved at a threshold injection current of 1.4mA at 77K. The laser emitted a blue wavelength at 462nm with a narrow linewidth of about 0.15nm. The laser beam has a divergence angle of about 11.7° with a polarization ratio of 80%. A very strong spontaneous coupling efficiency of 7.5×10−2 was measured.
Estimating the residue transfer of pesticides in animal feedstuffs to livestock tissues, milk and eggs: a review
Authors: MacLachlan D. J. , Bhula R.
Published: April 2008

The through chain approach to livestock production places increased emphasis on on-farm management systems for addressing pesticide residues. The current risk management paradigm assumes the user of animal feeds has the ability to assess, or at least profile, risks to trade in animal commodities associated with feeding livestock material containing residues of pesticides. The paper details some approaches that may be used by livestock producers, focusing on simple calculations, and summarises available information needed as inputs. Calculated factors for the transfer of pesticides from feed to animal commodities (transfer factors) are summarised for about 150 pesticides.
Notch pathway gene expression and wool follicle cell fates
Authors: Gordon-Thomson Clare , Botto Steven A. , Cam Graham R. , Moore G. Philip M.
Published: April 2008

The Notch family of genes has been implicated in specifying cell fates during hair follicle morphogenesis. We examined Notch gene expression during wool follicle formation, as an understanding of genes that influence cell distributions in the developing follicle is a prerequisite for devising molecular strategies to manipulate fibre characters and follicle density. We identified transcripts for the Notch1 receptor and one of its ligands, Jagged1, in fetal sheep skin by reverse transcriptase polymerase chain reaction. The sheep-specific cDNA sequences were used as templates to produce probes to investigate the expression patterns of Notch1 and Jagged1 in developing ovine fetal skin by in situ hybridisation. Notch1 and Jagged1 were detected in the epidermis and in a subpopulation of mesenchymal cells before follicle initiation. At day 70 during follicle initiation, transcripts were also detected in cells at the tip of the epidermal plug and in dermal condensates. By day 86, Notch1 and Jagged1 were detected in the distal cells of the epidermal downgrowths and epidermis and Notch1 was no longer detected in the mesenchyme and dermal condensates. After day 96, transcripts were absent from the epidermis, but localised to differentiating outer root sheath (ORS) cells. The distributions of transcripts implicate a Notch1–Jagged1 signal pathway in the fates of prospective ORS cells. The transient appearance of Notch1 in cells at the epidermal–mesenchymal junction during early follicle morphogenesis suggests that the receptor may be responsible for the specification of a cell subpopulation committed to a prepapilla fate at initiation.
The Timing of Responses to Spatial Perception-Questions
Authors: Cane V. R. , Horn V.
Published: April 2008

Examination of the time of response to single problems in spatial perception suggests that the approach of subjects to multiple-choice questions may differ from their approach to free-choice questions. There is some evidence for thinking that the slower subjects score more highly, and that practice in a given type of problem affects speed rather than correctness of response. These results may provide a new interpretation of some effects previously observed in repeated retesting of the same group.

The design of the experiment discussed was a “balanced incomplete block”, in which 120 subjects were required to answer 108 out of the total of 540 problems.
Sex Differences in Tactual-Kinaesthetic and Visual Perception of Vertically
Authors: Sandström Carl Ivar
Published: April 2008

Previous studies on visual and tactual-kinaesthetic perception with head tilted sidewise have shown that the greater deviations are to the left, i.e. the adjustments of a luminous line or a pivoting rod tend to fall counter-clockwise to the perpendicular. This paper shows significant sex difference in tactual-kinaesthetic perception only. Men and women show similar and small deviations to the right with head tilted to the left but, with head tilted to the right, women show clearly greater deviations to the left. The discussion of the visual perception of verticality (the so-called Aubert phenomenon) has been confusing. Our results in the visual experiments show small deviations, and they support Aubert's statement.
Some Effects of Severe Hypothermia on Learning and Retention
Authors: Andjus R. K. , Knöpfelmacher F. , Russell R. W. , Smith Audrey U.
Published: April 2008

Two experiments have been conducted to assess the effects of extreme hypothermia on learning and retention. In the first experiment two groups of rats were subjected to identical treatments except that the deep body temperature of one group was lowered to between + I° and o° C. before both groups began learning a serial problem solving task. The second experiment included three groups of animals: a control and two experimental groups, the deep body temperature of animals in one of the latter being reduced to between + 13–4° and + 18–5° C. and that of the other to between + I° and o° C. Except for the “hypothermia” phase of the design all groups in the second experiment received identical treatments in the following order: Training on a maze, hypothermia, tests for retention of the maze habit, training on the serial-problem-solving task, tests for speed of locomotion.

Animals whose body temperature had been lowered to between + I° and O°C. showed a significant impairment in learning performance when compared with control animals. On the other hand, no significant differences were found between the performances of control animals and those cooled to between + 13.4° and + 18.5°C. The results also suggest that the effects of severe hypothermia may be temporary, since the percentage of impairment decreased as the interval between body cooling and learning increased.

The differences in retention of the maze habit among experimental and control groups were very small and in no instance were they statistically significant, although there was a consistent trend towards poorer retention following hypothermia. These small differences may be functions of the technique used to reduce deep body temperature rather than of the effects of hypothermia per se.

These results are based upon observations of the behaviour of non-hibernating, homoiothermic animals. With such animals, extreme hypothermia, such as that employed in the present study, results in complete arrest of heart beat, circulation, and respiration. It also suppresses electrical activity in the brain and in our animals cerebral activity may have been arrested for as long as 13 to z hours. Within the limits of our experimental procedure we have failed to find evidence that arrest of these vital metabolic processes as a result of hypothermia produces any very serious, permanent effects on the animal's behaviour once it has been successfully reanimated. If, as previous writers have suggested, severe hypothermia can be used to “… stop all nerve impulses in the brain momentarily …” (Gerard, 1953), our results are difficult to explain if long-term memory is dependent upon the continuous activity of the brain.
The Physical Properties of Bar-Pressing Behaviour and the Problem of Reactive Inhibition
Authors: Trotter J. R.
Published: April 2008

Many of the terms used in the literature on reactive inhibition are vague, subjective or incorrect. The weighted bar is not a suitable device in the study of this problem, since it records irrelevant aspects of behaviour. An experiment using apparatus which gives a continuous record of the force which a rat applies to a knob produces the following results. After much practice, pressing becomes sharp and brief and the amount of activity per reward is reduced. Under conditions of no (intentional) secondary reward the amount of activity during extinction is at first positively correlated with the average activity per reward during training, but the correlation diminishes as extinction proceeds. With auditory secondary reward there is no correlation.
Studies in Olfactory Acuity. II.: Relative Detectability of n-Aliphatic Alcohols by the Rat
Authors: Moulton D. G. , Eayrs J. T.
Published: April 2008

The ability of albino and black rats to detect n-aliphatic alcohols in the vapour phase has been investigated and probit analysis used to evaluate the results. At median threshold (= 50 per cent, success level) detectability tends to increase by logarithmic increments as the number of carbon atoms in the molecule is increased. However, a similar but reverse relationship occurs between carbon chain length and the gradient of the probit regression lines; and detectability at the 85 per cent. success level, as estimated by interpolation, shows a trend towards oscillation. It is suggested that this finding can resolve the apparent conflict in the literature concerning the pattern of odour intensity in homologous series, and that it may reflect the influence of low water solubility in limiting response to high concentrations of longer chain alcohols.

When expressed as pressures, median threshold values for alcohols in the rat vary directly with saturated vapour pressures; when expressed as thermodynamic activities intermediate and longer chain alcohols appear to be equally stimulating, whilst short chain alcohols show decreasing activities as the series is ascended. In several of the relations considered the position of methanol and dodecanol appears anomalous.
Experimental Disorientation and Conceptual Confusion
Authors: George F. H. , McIntosh S. B.
Published: April 2008

Thirty-two subjects were examined on a visual matching task. They were tested for their ability to maintain an orientation with respect to a particular direction in the horizontal plane, while being kept in circumstances designed to minimize their input of information and create thereby some conceptual confusion.

The results suggest that subjects tend to make corrections as if they were in the same position in space throughout, even though they have no necessary reason for supposing this to be true and some reasons for supposing the opposite. It seemed that non-verbal information had to be presented to the subjects in order to suppress this tendency.

Voluntary rotation of the subject from one setting to the next produced no more than chance errors, while arbitrary rotations only produced errors when cues were inconsistent, or possibly where no cues were available at all. In the cases where no cues—or minimal cues-were available, assumptions were made by the subjects about the nature of the environment. This caused both errors and correct responses for reasons that were not justified by the evidence in the hands of the subject.

Introspective reports revealed some interesting results as to the cues utilized and concepts consciously formulated by the subjects for their use.
Choice Reaction Times for Skilled Responses
Authors: Mowbray G. H.
Published: April 2008

Two kinds of choice reaction time experiments are reported, both of which make use of a highly overlearned sensori-motor response. When a response is required for each stimulus presented, no increase in reaction time occurs as a function of the number of alternative stimuli available. It is proposed that the increase in choice reaction times commonly thought to accompany an increase in the number of alternative choices provided reflects the unpractised state of the responder. When a response is required for only one out of n possible stimuli, a slight but consistent increase in reaction time takes place with an increase in the number of alternatives. An analogy is drawn between the second experiment and a vigilance task and an expectancy hypothesis is invoked to explain the results.
Studies in Olfactory Acuity: III. Relative Detectability of n-Aliphatic Acetates by the Rat
Authors: Moulton D. G.
Published: April 2008

The ability of black and albino rats to detect the first seven n-aliphatic acetates in the vapour phase has been investigated by use of an odour choice box. Both the median threshold and the slope of the probit regression line (which describes the relation between concentration and response) tend to decrease logarithmically in value as the series is ascended. The position of methyl acetate in these relations appears anomalous. When expressed as thermodynamic activities median thresholds for acetates of intermediate chain length are about equally stimulating, whilst short chain alcohols excite at decreasing activities with increasing chain length. The close similarity of these findings to those reported in the previous study on n-aliphatic alcohols supports the view that such relations may be of more general occurrence in olfaction in the rat.

The stimulus-response curve for each acetate studied shows one or more reversals in slope. It is suggested that certain of these are due to the presence of two or more olfactory receptor types one or more of which attain maximum response at lower concentrations of a given acetate than do the remainder. The asymptotes of the curves are reached in about 2–3 log units of concentration.
An Experimental Synthesis of the Associations and Gestalt Accounts of the Perception of Size. Part III
Authors: Joynson R. B. , Kirk N. S.
Published: April 2008

Two control experiments are described which are concerned with the effect, on judgements of size, of varying the angular separation of the compared objects in the horizontal plane. The first experiment investigates order effects. The second experiment compares judgements of real size at small and large angles of separation. The findings are discussed in relation to parts I and II of these papers.
Contextual Cues in Selective Listening
Authors: Treisman Anne M.
Published: April 2008

Two messages were presented dichotically and subjects were asked to “shadow” whatever they heard on one ear. Somewhere in the middle the two passages were switched to the opposite ears. Subjects occasionally repeated one or two words, at the break, from the wrong ear, but never transferred to it for longer than this. The higher the transition probabilities in the passage the more likely they were to do this. One explanation might be that the “selective filter” (Broadbent, 1958) acts by selectively raising thresholds for signals from the rejected sources rather than acting as an all-or-none barrier.
Falling Through the Gaps: Safeguarding Children Trafficked into the UK
Authors: Bokhari Farrah
Published: April 2008

An overview of child trafficking in the UK explores the nature and methods of this abuse, as well as the treatment and protection afforded to these particularly vulnerable children. It highlights the shortcomings and inconsistent standards of local authorities, the lack of specialist protection and the uncertainty of a trafficked child’s immigration status, combining to make these children vulnerable to further harm and at risk from the influence of their traffickers. A stark consequence of this has been the disappearance without trace of many children from local authority care and the mental health issues of trafficked children going undetected and untreated. For the sake of clarity some of the terms used in this paper are defined as: (i) child: the definition of a child is of someone up to 18 years of age as set down by the United Nations Convention on the Rights of the Child, 1989 and UK legislation including the Children Act, 1989 and 2004. (ii) separated child: this term is used instead of ‘unaccompanied asylum‐seeking minor/child’. A separated child is one separated from her/his parents or primary guardian. This definition is more useful because not all trafficked children who seek asylum are unaccompanied on arrival and not all trafficked children apply for asylum.
ORIGINAL ARTICLE: Why is habitat breadth correlated strongly with range size? Trends amongst the alien and native floras of Mediterranean islands
Authors: Lambdon Philip W.
Published: April 2008

Aim  To identify the factors determining the relationship between habitat breadth and range size in the Mediterranean alien flora. Strong relationships have previously been uncovered between the two variables, which raises the possibility that habitat breadth could be used as a powerful predictor of invasiveness. However, previous investigations have yet to explain the phenomenon adequately, and greater understanding is required to establish its importance.

Location  Ninety‐one islands in the Mediterranean basin.

Methods  I examined a data base of Mediterranean naturalized plant species created for the EU project EPIDEMIE, and containing information on island distributions, habitat occupancy and other descriptive parameters compiled from published floras. As a null hypothesis, I assumed that the relationship between habitat breadth and range size was a spatial scale artefact: if species colonize habitats at random, with the likelihood determined by a weighted probability in each habitat, then perceived habitat breadth will increase with the number of populations examined. I modelled this effect, and also considered circumstantial evidence (via indirect indicator variables) for six hypotheses to determine whether both habitat breadth and range size may be jointly driven by a major third factor (introduction frequency, residence time, dispersal ability, generation time, dependence on mutualisms, release from herbivory). The explanatory power of the hypotheses was compared using correlative statistics.

Results  When habitat breadth was modelled according to the null hypothesis, the form of its relationship with range size was very similar to that from the observed data, and the predicted range size estimates explained almost half the observed variance. The unexplained component may have been due to the same mechanism operating at finer spatial scales. From the direction of the residual effect, increases in habitat breadth were probably driven by range size rather than vice versa. None of the alternative hypotheses were found to be significant predictors of habitat breadth and range size in invasive species.

Main conclusions  Although a number of minor explanations cannot be ruled out (e.g. that widespread species have greater regional genetic diversity enabling them to adapt to local conditions), it seems likely that the habitat breadth effect is largely artefactual and does not have particularly great value as a predictor of invasiveness.
Databases in the classroom*
Authors: & D. Freeman , Tagg W.
Published: April 2008

Handling information on a variety of media from difference sources has always been an integral part of learning. Children now have the opportunity to use information‐handling programs on microcomputers that support the existing curriculum and open up new possibilities for self‐directed enquiry learning. This paper summarizes the background to the development of the QUEST ‘family’ of programs and demonstrates the way they are used in History and Geography. Comparisons are also made with other database programs.
Learner control in computer‐assisted learning*
Authors: Holmes N. , Robson E. H. , Steward A. P.
Published: April 2008

Cognitive theorists believe that students should be active in organizing their learning. Thus learner control may assist learning directly and promote good strategies.

A teaching programme is described that offers to the student control over content, style and level of difficulty. The material was delivered by PET microcomputer and the subject was binary arithmetic. Four groups of young secondary schoolchildren were exposed to different treatments of the same material.

The treatments were:

learner control;

learner control with advice;

random program control;

adaptive program control.

The effect of advice on pupil's choices was clearly evident. The random group performed less well than the other groups but no differences were observed between learner and adaptive control.
A perspective on intelligent computer‐assisted learning*
Authors: Self J.
Published: April 2008

The recent impressive developments in intelligent knowledge‐based systems design have led inevitably to proposals to design intelligent tutoring systems along similar lines. At the core of such a tutoring system is an ‘expert system’ able to perform whatever task the learner is to master. This methodology focuses on expertise, views actual student behaviour as deviant and encourages conformance to some predetermined standard. This paper describes an alternative research strategy involving the design of ‘guided discovery learning’ systems built around machine learning programs.
Problem solving with spreadsheets*
Authors: Catterall P. , Lewis R.
Published: April 2008

The recent availability of spreadsheets has provided new opportunities for pupil and student use of microcomputers. Whilst much has been written on the use of database and word processing packages, the educational uses of spreadsheets is relatively undocumented. In this paper reference is made to exploratory work aimed at providing opportunities for additional experience in problem solving.
The development of an educational computing course for initial training of primary teachers
Authors: Layman J. , Hall W.
Published: April 2008

Abstract Current literature in educational computing concentrates on the creation of better software and more in‐service training to maintain the impetus in the use of microcomputers in the classroom. This approach often ignores the vital role to be played by educational computing courses in initial teacher training, the content of which is much under‐researched. This paper outlines the development of one such course at La Sainte Union College of Higher Education, in which the student teachers were asked to work at an early stage with groups of children using micro‐computers. The results are very encouraging and specific conclusions are presented and discussed. These may be of interest to others involved with formulating policy and the provision of new technology courses in initial teacher training.
Teachers encounter PROLOG
Authors: Nichol J. , Dean J. , Briggs J.
Published: April 2008

Abstract A major problem in introducing computing into schools is how to teach teachers programming and give them confidence to write programs which they can use in their class‐rooms. The Exeter Project, originally into PROLOG and History teaching, has experimented with a new user‐friendly front‐end to PROLOG, called MITSI (Man In The Street Interface), and has written teacher oriented documentation for the existing front‐end, SIMPLE. This article analyses teacher's responses to the Project's two latest programming courses, and suggests that PROLOG programming, using appropriate front‐ends, might be a particularly successful medium for Humanities teachers.
Experience in introducing sixth formers to concepts of artificial intelligence
Authors: Casey C. , Adewumi A. O. , Hart A. , O'Hare G.
Published: April 2008

Abstract  This paper describes material presented to sixth‐form students, and their reactions to it. The material was specially designed to introduce the main principles of artificial intelligence, and to open up some of the practical issues involved in its use and development. The authors make tentative suggestions about the usefulness and importance of such work in the school curriculum. Further details of the work and results are available on request.
Students' attitudes towards control methods in computer‐assisted instruction
Authors: Hintze H. , Mohr H. , Wenzel A.
Published: April 2008

AbstractComputer‐assisted instruction (CAI) has been used in the teaching of dental students for the last decade at the Royal Dental College Aarhus, Denmark. In oral radiology a number of programs structured according to different teaching principles have been available. The aim of this study was to investigate students' attitudes to three main structures: a fully teacher‐controlled structure (TC), a menu based structure with partial learner control (structural communication, SC), and a fully learner‐controlled structure (LC) applied on programs for oral radiology. Fifty‐seven students were interviewed. Most students (53%) preferred the LC structure, and 56% recognized that they had most influence on program progression in this structure. Male and female students' attitudes differed, however, as significantly more males than females preferred the LC structure (p< 0.05). No statistically significant differences were found between the two sexes when asked which structure provided the greatest learning effects and learner influence, but the female students found the SC as efficient as the LC structure.
The database as a catalyst – a year with QUEST
Authors: Smart L.
Published: April 2008

Abstract A great deal has been written about the contribution a database can make to enhancing children's learning and particularly their thinking. Much, if not most, of this material has been concerned with children of post‐primary age and it has examined the uses made of the database through the traditional subjects. This article is an attempt to illustrate how the database software QUEST was used continuously over a school year with 10/11‐year‐olds operating in a multidisciplinary, project‐based approach. It claims that the database acted as a catalyst, encouraging and actively promoting a wide range of learning situations that might not have otherwise occurred.
Handwriting versus wordprocessed print: an investigation into teachers' grading of English Language and Literature essay work at 16 +
Authors: Peacock M.
Published: April 2008

Abstract Selections of English Language and Literature CSE (now GCSE) course work essays are graded by a total of 411 teachers in two forms: handwritten and wordprocessed. Mistakes in the original handwritten versions are not edited out. It is found that the wordprocessed English Language essays are, on average, marked up a grade. However, it is found that relatively high quality English Literature work is not affected. Results suggest:

— that the less directly pupil work is specifically related to an external referent (such as a work of literature), the more likely it is that computer‐assisted methods of presentation will significantly enhance its apparent quality relative to handwritten work.

— that relatively lower quality work will tend to be enhanced more than relatively higher quality work.

The implications of the results for examination boards are also considered.
From consumer awareness to econometric analysis: the use of CAL throughout economics education
Authors: Welford R.
Published: April 2008

Abstract  This paper examines the use of CAL as a progression throughout economics education beginning at an economic awareness level and ending with a brief look at the use of computers for econometric analysis. Key pieces of software are identified and the environment in which they can be used is examined. The techniques and approaches to the use of the computer at all levels are shown to have similarities. Throughout the paper computers are shown to enhance the study of economics which in turn leads to comments about the future of CAL in economics and the content of the ‘core’ in economics education.
The evolution of a national research plan for computers in education in The Netherlands
Authors: Moonen J. , Collis B. , Koster K.
Published: April 2008

Abstract This paper describes the evolution of a national research plan for computers and education in The Netherlands. This approach was initiated in 1983 and includes two phases: one from 1984 until 1988 and one from 1989 until 1992. The paper describes the research plans for the second phase, based upon the experiences of the first, and draws some general conclusions about the development of national research plans for computers in education.
Designing a LOGO‐based microworld for ratio and proportion
Authors: Hoyles C. , Noss R. , Sutherland R.
Published: April 2008

Abstract This paper reports the results of the first part of a study to design, implement and evaluate a LOGO‐based microworld for ratio and proportion. The microworld provided pupils (of 12 ‐13 years‐of‐age) with pre‐written LOGO tools which could be used and explored in terms of their internal and external relationships; pupils were given opportunities to create and explore their own programs. The microworld was implemented in a class of 24 children with the researchers acting as teachers. Evaluation took the form of (i) paper‐and‐pencil pre‐ and delayed post‐tests; (ii) audio recorded interviews with nine pupils subsequent to both tests; (iii) process data during the microworld implementation.
Making sense of the future
Authors:   Educational Technology Center Harvard Graduate School of Education
Published: April 2008

Abstract  Since 1983, the Educational Technology Center has studied the uses of computers and other technologies to improve K‐12 instruction in science, mathematics and computing. Our collaborative research groups‐including scientists and mathematicians, practising teachers, learning theorists and software designers‐have focused on ‘targets of difficulty’, or curricular topics that are both crucial to students' further progress in these fields and widely recognized as difficult to teach and learn. More than fifteen research projects have studied the nature of students' difficulties, clarified the educational advantages that computer technology offers and designed experimental lessons that use computers as well as traditional materials to address these difficult topics. During the past year, three research groups tried out promising teaching units in five Massachusetts high schools to learn about their use in regular classrooms and schools. This essay summarizes the results of the Educational Technology Center's work and their implications for policymakers, school practitioners and others concerned about science and mathematics education.

Neither a technical report nor a formal proposal with references, data tables and methodological detail, it is intended to stimulate discussion on this important topic.
The assessment of IT capability
Authors: Birnbaum I.
Published: April 2008

Abstract  The 1988 Educational Reform Act established in England and Wales a National Curriculum which sets out in statute assessment objectives and teaching programmes for a range of subjects. IT plays an important part in this Curriculum, and is intended to permeate it in a natural way. Since IT has its own objectives‐relating to what is termed IT capability‐this raises particular problems of cross‐curricular, context‐led assessment, which this paper explores. In doing so, the paper sets up a model of pupil progression for IT capability development, which provides a theoretical basis to the practical problems of assessment.
Promoting creative confrontations
Authors: Brna P.
Published: April 2008

Abstract We outline a methodology for confronting students with the inconsistencies entailed by their own beliefs. We illustrate this with reference to one particular physics subdomain which stresses an understanding of process (how things are made to happen): the dynamics domain.

The aspects of the methodology described are: the construction of a variety of situations which are expected to cause a student some conceptual difficulty; the predictions made by the student prior to modelling; and the observations of the student's attempts to model the situation. We use a case study to illustrate the approach.
Naked into the World: IT experiences on a final primary school teaching practice—a second survey
Authors: Dunn S. , Ridgway J.
Published: April 2008

Abstract This study reports a survey of 103 student teachers who were asked about their experiences of IT on their final teaching practice. Data are related to those from an earlier survey of the same group of students on their first teaching practice. The use of IT was higher than before, but still unacceptably low. A large majority of students will graduate with no classroom experience of databases and other applications software; a significant number will graduate without any classroom experiences using IT whatsoever. The patterns of IT use in class were most disappointing. A predominant use was for pupils to work on tasks unrelated to lesson plans, often practising basic skills.

Those students who had taken a course in computer studies were more confident in their use of IT, made more use of IT in class, and experienced fewer technical problems than students who had not taken this course. However, students who had taken this course were no more likely to use a computer in class than those who had not. Students who do use IT in class reported increased confidence and a desire to make greater use of IT in the future. It is concluded that compulsory courses on the educational uses of IT, and use of IT early in teaching practice will help improve the current unacceptable situation, so long as they address the problem of ensuring appropriate classroom use of IT by students.
IT capability in primary initial teacher training
Authors: Wild P. , Hodgkinson K.
Published: April 2008

Abstract  All courses in initial Primary teacher training are now required, through the Council for the Accreditation of Teacher Education (CATE), to provide information technology (IT) capability across primary school subjects as well as providing for those elements of IT that are specified within the National Curriculum Documents. As a starting point for this process at one institution, a survey of students on the 36‐week Post Graduate Certificate of Education (PGCE) primary course showed that their initial capability and awareness was very low. A restructured course programme was monitored by means of pre‐ and post‐course surveys of capability, by students' own records and by the tutor's subjective field notes during teaching and student IT activities. This paper includes a description of the course together with the results of the surveys and suggests that increasingly individualised learning strategies will considerably enhance this aspect of initial teacher training.