bluuebunny/crossref_metadata_2025 huggingface dataset:
Parental Power and Special Educational Needs: the case of specific learning difficulties
Authors: RIDDELL SHEILA , BROWN SALLY , DUFFIELD JILL
Published: June 2007

Research on parents of children with special educational needs has revealed their lack of power and the difficulty of establishing genuine partnership with professionals. This paper focuses on a predominantly middle‐class group, parents of children with specific learning difficulties. In the light of the Government's recent emphasis on parental rights, the paper explores what educational provision these parents want for their children, the strategies they employ to achieve their goals, the extent of their success and the implications of their actions for other parents of children with special educational needs. It is argued that parents of children with specific learning difficulties, well supported by voluntary organisations, are able to fulfil the role of critical consumer envisaged by government and have enjoyed a measure of success in arguing for improved levels of resourcing. Few would argue that services for children with specific learning difficulties are adequate. However, there are other groups of children with special educational needs, particularly those previously described as having mild/moderate learning difficulties, for whom provision may be worse and who do not have a powerful advocacy group to promote their cause.
The Paradox of Gender: sex stereotyping within statementing procedure
Authors: Hill John
Published: June 2007

This paper seeks to document a previously neglected area of study, namely the influence of gender in the process of statementing. It will be the intention of the analysis to show, through a quantitative and qualitative investigation of selected data, how the content of statements differ when examined from a gender perspective. Evidence presented will be in the form of an analysis of 50 statements collected from the local education authorities in Sheffield and Rotherham. Reference will be made to the terminology used both by teachers and psychologists in determining, through statementing advice, those children perceived as having moderate learning difficulties. Conclusions from this analysis will show how the statementing system is not a neutral process, and its institutionalisation within the educational bureaucracy has made it generally reflective of dominant values and beliefs. In this way, it will be argued, gender differentiation has become part of a wider process which separates some children (i.e. to special schools) from others. A further feature of this analysis will be a discussion both of the way in which the data contribute to new understandings in the field of gender and education and some of the policy implications which emerge from it.
The Politics and Ethics of Educational Research in England: contemporary issues
Authors: Simons Helen
Published: June 2007

Government sponsored educational research is increasingly subject to contractual control over the design of the research, dissemination and publication and even the research process itself. This paper argues that this current policy context poses a threat to the quality of educational research and places severe limitations on the contribution it can make to the generation of public knowledge and the utilisation of research in educational policy‐making and public debate. Focusing upon two contemporary issues—restrictive research contracts and conditions and the changing nature of ethical guidelines—the paper explores how the political context of recent years has led to changes in research contracts and ethical and political responses of formal associations. The paper concludes by examining a number of positions the educational research community can take in such a restrictive political climate, arguing, in particular, that professional organisations need to act both collectively and politically if they are to make any inroads into improving contractual conditions to protect quality research.
Bullying as a Formative Influence: the relationship between the experience of school and criminality
Authors: Cullingford Cedric , Morrison Jenny
Published: June 2007

Most of the research literature on schools has focused on school management, organisation, the curriculum and teaching. There is comparatively little research on the experience of school from the point of view of children. Despite growing concern, and an increase in strategies to combat bullying, relatively little is known about the nature and underlying causes of the phenomenon. The overall concern of this research is to explore the correlation that has been found between bullying in school and the development of criminality. Lengthy, semi‐structured interviews were conducted with 25 young offenders aged between 16 and 21 in order to explore childhood memories and retrospective accounts of their whole experience of school. The findings were highly consistent, not in terms of factual and personal details, but in terms of tone, attitude and circumstance. From the point of view of young offenders bullying was part of the ethos of the schools. The problem is not a matter of clearly isolated incidents and individuals. It is pervasive in the social life of school, and therefore all children are affected by it in one form or other. Any understanding of the problem can only be achieved by moving away from the overwhelming concentration on typical ‘bullies’ and ‘victims’ as many have experienced both of these roles.
Students as Researchers: rationale and critique
Authors: Atweh Bill , Burton Leone
Published: June 2007

The paper explores the background and implementation of a project in which school students researched the factors which affect the decision to remain at school or leave at 16. The two major concerns of the project were equity and access to higher education. It was the result of a collaboration between researchers from the University of Birmingham, school teachers and school students. A critique is offered of the method of students as researchers focusing upon five main issues, organisation, time, equity, research style and clashing cultures.
Fashioning Post‐modernism, Finishing Modernism: tales from the fitting room
Authors: Stronach Ian
Published: June 2007

This article sets out to examine the policing of the so‐called ‘borders’ of ‘modernism’ and ‘post‐modernism’, arguing that such polarising metaphors are distinctions that cannot be made without self‐contradictions that would make even a post‐modernist blush. Instead, we must deconstruct the notion of boundary or border, drawing on Derridean formulations of difference in the fields of literature, feminism and post‐colo‐niality: what new metaphors of difference are possible, and what do they imply for the ‘essentialisms’ of educational ideals, or for notions of sexual, ethnic, or cultural identity? The ambition of the article is to explore a way of deconstructing the unspeakable ‘slash’ between modernism/post‐modernism that can model how similar arguments may be deployed against a wide range of educational topics where questions of identity and difference are brought to the fore, such as equal opportunities, special needs, antiracism, as well as more mundane categories of pupil or teacher — or researcher — identity. It fails, of course, but perhaps interestingly enough to encourage further explorations in such directions.
Peer Group Pressure Within and Outside School
Authors: Cullingford Cedric , Morrison Jenny
Published: June 2007

This paper is based on an empirical study of a sample of 25 young people who have all had the experience of being excluded from school (and who are all young offenders). The research was based on qualitative explorations and memories of the subjects' overall experience of school, through lengthy semi‐structured interviews. These interviews were designed to elicit information in an open way through the encouragement to talk confidentially and anonymously. There were no preset hypotheses, so that the consistency of the responses, including the terminology used, is significant. Amongst others, four main themes emerged; the experience of bullying; the significance of home life and its relation to school; the pressure of peers; and the relationship between truancy and exclusion. It is the issue of peer group pressure in particular that will be explored here. As the case‐studies reveal, the relationship between peer pressure and deviancy is a complex one. It did, however, emerge from the analysis that the peers are a powerful influence on the behaviour of adolescents, although in some ways these are unexpected. The paper explores the way in which peer group pressure relates to the counter influences of home and school.
Focus Groups: a useful qualitative method for educational research?
Authors: Wilson Valerie
Published: June 2007

During 1994‐95, a small team of researchers at the Scottish Council for Research in Education (SCRE) undertook a commissioned study of adults’ perceptions of their lifestyle options within a Scottish region. The findings of the research were intended to inform initiatives in health education and promotion. Two methods of data collection were employed: in‐depth interviews and focus group meetings. In this article, the researcher reflects on one of those methods — focus groups — which has been used extensively in market research, and explores (a) what focus groups are, (b) how they have been utilised by researchers and (c) some of the practical and theoretical implications for incorporating focus groups in the design of educational research projects, paying particular attention to issues of data generation.
‘Gendered Citizenry’: new feminist perspectives on education and citizenship
Authors: Arnot Madeleine
Published: June 2007

This paper describes the recent development of feminist analyses of the role of education in creating ‘inclusive’ democratic citizenship. Four discrete feminist perspectives on citizenship are outlined: a theoretical critique of citizenship as a modern male narrative; a socio‐historical perspective on women's struggle for equal citizenship through education; deconstruction of the discourses of citizenship used by contemporary teachers and their gendered dimensions; and an emerging educational perspective on the gender principles which should affect education for citizenship in democratic societies. These four perspectives on citizenship offer opportunities to reflect critically on the past and continuing struggle of women for equality. They suggest, too, the complex issues which now face any programme of education for citizenship for the next century. More than one masculinised democratic discourse, it seems, would need to be transformed for women to achieve full political integration.
A Study of Student Teachers’ Perceptions of Teaching the Arts in Primary Schools
Authors: Green L. , Chedzoy S. , Harris W. , Mitchell R. , Naughton C. , Rolfe L. , Stanton W.
Published: June 2007

Recent reform of initial teacher education has changed the balance of school‐based training of students and has increased teachers’ responsibility for training them in schools. This article reports on a preliminary study of primary undergraduate student teachers’ perceptions of their experience in schools on their second year and final teaching practices. Through questionnaires and structured interviews we sought students’ views of the effectiveness of university‐based courses in preparing them to teach the arts and their perceptions of the support given to them by teachers in training them to teach art, dance, drama and music in schools. The findings raised concerns about the quality of experience currently being offered to students by teachers. Indications were that the number of students able to learn from the teachers about the four subjects was significantly low. The students’ comments suggested that existing teacher expertise in these subjects was lacking and this raises issues regarding school‐based initial teacher education as well as in‐service training for teachers.
Summer of Discontent
Authors: Katyal Anjum
Published: June 2007

RELIGION, CENSORSHIP AND THE POLITICS OF OFFENCE
God's Gift to China
Authors: Xiaobo Liu
Published: June 2007

PRAISE THE LORD AND KEEP ON BLOGGING
Dangerous Dyads Revisited: Democracies May Not Be That Peaceful After All
Authors: Buhaug Halvard
Published: June 2007

In recent years, the quantitative international relations literature has increasingly paid attention to the potential problem of serially correlated observations in time-series cross-section (TSCS) data. Today, no study using TSCS data is published unless it manages to control for temporal dependence. Using Bremer's (1992) seminal “Dangerous Dyads” article as a starting point, this article has two ambitions. First, it seeks to explore whether the original results are replicable with new and updated data. Second, it aims to uncover whether Bremer's now unconventional choice of statistical model was decisive for his results. The analysis shows that despite clear evidence of serially correlated units, the alternative logit, GEE, and survival models yield relatively similar results. However, Bremer's finding of a monadic democratic peace is not robust to various operationalizations of democracy. His choice of democracy indicator thus seems to have had a significant influence on his conclusions, demonstrating that data selection can be as crucial as the choice of statistical model.
Development and Validation of a Mathematical Model to Describe Anti‐Cancer Prodrug Activation by Antibody‐Enzyme Conjugates
Authors: Jackson Trachette L. , Senter Peter D. , Murray James D.
Published: June 2007

A mathematical model has been developed for a two‐step approach to cancer chemotherapy involving the use of targeted monoclonal antibody‐enzyme conjugates for the selective activation of anti‐cancer prodrugs. Theoretical analysis and numerical simulation are used to characterize critical parameters for intratumoral and systemic drug generation. The model suggests that the most important pharmacokinetic and clinical parameters for increased drug production in the tumor are the rate of prodrug clearance from the blood and the initial injected dose of prodrug. The physiological parameters with the most influence are the prodrug and drug permeability. The ratio of tumor to blood drug generation can best be improved by increasing the conjugate clearance from the blood and decreasing the rate at which prodrug is converted to active drug. Predictions from this model concerning intratumoral prodrug and drug levels are validated by comparison with experimental data. Finally, the effects of certain barriers to chemotherapeutic treatments including vascular heterogeneity and radially outward convection are studied. If vascular heterogeneity alone is considered, the model predicts that the highest drug levels will occur in the most poorly vascularized sections of the tumor. However, when the effects of convection directed radially outward is considered, the highest drug levels are seen in the semi‐well vascularized regions. This implies that the rapidly growing periphery of the tumor and the semi‐necrotic tumor interior will receive the least amount of drug. These mathematical model predictions can lead to improved treatment protocols for this two step approach to cancer chemotherapy.
Mathematical Model of Airflow in the Lungs of Children I: Effects of Tumor Sizes and Locations
Authors: Segal R. A. , Guan X. , Shearer M. , Martonen T. B.
Published: June 2007

To contribute to the development of more effective aerosol therapy protocols in pediatric medicine, we examined airflow patterns in the lung of a four‐year‐old child. In particular, we addressed how the presence of tumors in airways affected the character of airflow patterns. To study the effects of tumors we employed a computational fluid dynamics package, FIDAP, to define flow conditions within a model lung. The results indicated that tumors have a pronounced affect on both (i) localized velocity profiles in airways and (ii) bulk flow distribution within the lung. By identifying the effects of physical factors on flow conditions the findings will lead to improved drug delivery regimens.
Autoselection Phenomenon in the Normal Cell Clone Undergoing Differentiation: From Cell Population Heterogeneity to Cancer Phenotype via Nonmutational Changes
Authors: Solyanik Galina I. , Serikov Alexander A.
Published: June 2007

The problern of regulation of the proliferation‐differentiation processes is analysed in the framework of the model of unipotential cell clone dynamics, assuming two alternative ways (scenarios) of an every new‐born cell development, which in the long run define correspondingly the proliferating or differentiated cell status. The scenario choice is then supposed to be a random event influenced by both the inherent mitotic activity of the cell and the differentiation factors — special messengers synthesized by the differentiated cells. Differentiation factors being accepted by every‐new born cell can change the way of cell development. Taking into account the clonal heterogeneity it was shown that such mechanism of the regulation of proliferation‐differentiation processes can result in the selection of actively proliferating and insensitive with respect to differentiation factors action cells (that is to say, the cells with cancer phenotype). In the framework of investigation the cells with cancer phenotype (which is heritable within the variability of mother‐daughter correlations)appears through the series of the permanent nonmutational changes in the proliferating cells by autoselection mechanism retaining for the division and generation of the progeny only that actively proliferating cells which are less sensitive with respect to the action of the differentiation factors. The progression of normal cell clone towards the appearance and increase of the number of the cells with cancer phenotype can be considered as a possible mechanism of carcinogenesis which is alternative to the clonal selection theory of cancer origin.
A Mathematical Tumor Model with Immune Resistance and Drug Therapy: An Optimal Control Approach
Authors: De Pillis L. G. , Radunskaya A.
Published: June 2007

We present a competition model of cancer tumor growth that includes both the immune system response and drug therapy. This is a four‐population model that includes tumor cells, host cells, immune cells, and drug interaction. We analyze the stability of the drug‐free equilibria with respect to the immune response in order to look for target basins of attraction. One of our goals was to simulate qualitatively the asynchronous tumor‐drug interaction known as “Jeffs phenomenon.” The model we develop is successful in generating this asynchronous response behavior. Our other goal was to identify treatment protocols that could improve standard pulsed chemotherapy regimens. Using optimal control theory with constraints and numerical simulations, we obtain new therapy protocols that we then compare with traditional pulsed periodic treatment. The optimal control generated therapies produce larger oscillations in the tumor population over time. However, by the end of the treatment period, total tumor size is smaller than that achieved through traditional pulsed therapy, and the normal cell population suffers nearly no oscillations.
A Mathematical Model for Cellular Locomotion Exhibiting Chemotaxis
Authors: Holmes M. J. , Sleeman B. D.
Published: June 2007

A fundamental problem of cellular biology is to understand the mechanisms underlying cellular locomotion. Bacterial organisms may use appendages such as flagellae or cilia to facilitate motion. Amoeboid motion [6], exhibited by eucaryotic cells are seen to flatten onto surfaces and extend thin sheets of cytosol called lamellipodia. These in turn make attachments to the surface and by the initiation of internal contractions within the cell, a forward motion is achieved. The processes which govern this behaviour are extremely complex, however, key ingredients have been identified which may provide a sufficient basis for persistent cellular motion. These factors are osmotichydrostatic expansion and cellular contraction mediated by intracellular calcium ca2+. In this paper, we develop a simple two dimensional model for a non‐muscle motile cell based on these two key factors. We show it is capable of producing persistent cellular motion and chemotactic behaviour.
A Model of Dispersion in Perifusion Systems
Authors: Shorten Paul R. , Wall David J. N.
Published: June 2007

The perifusion apparatus is an experimental tool used to model information transfer in endocrine systems. The major drawback of the perifusion system derives from the dispersion, diffusion and mixing of the hormone within the apparatus which distort the original released hormone concentration profile. In this paper we develop a mathematical model of the perifusion system that accounts for a number of observable features in the measured secretory profile. We also consider associated inverse problems, the solution of which enhance perifusion data measurements and unmask the underlying secretory events. In contrast with the raw data, the deconvolved data supports the concentration dependent, rapid activation of CRH‐induced ACTH secretion. The perifusion chamber can be modeled by an advection‐diffusion equation, and we develop general theory analysing the validity of this approximation. We also provide a characterisation of the degree of ill‐posedness of the inverse advection‐diffusion equation in terms of the perifusion parameters.
On Distributions of Physiological and Anatomical Variables in Pathological Conditions: Dopamine D2 Receptors in Schizophrenia and Their Occupancies after Drug Treatment
Authors: Tuckwell Henry C.
Published: June 2007

If a physiological, biochemical or anatomical variable has a normal distribution then the tails of such a distribution may be associated with pathological function. In certain cases this can lead to a bimodal distribution for the variable in individuals with the resultant pathology. We illustrate with a study of dopamine receptors. PET data suggest that the distribution of dopamine DA2 receptor densities in schizophrenic patients might be bimodal. A quantitative model based on the classical theory of drug action and a simple differential equation for receptor synthesis and degradation is used to estimate the effects of neuroleptics on D2 receptor occupancy. It is found that individuals in the upper tail, with higher than normal receptor densities, may eventually attain an equilibrium D2 occupancy after treatment which is in the normal range, whereas individuals with lower than normal receptor densities are predicted to have equilibrium D2 occupancies after treatment which may fall below normal values. Thus, a factor which might determine whether there is a successful outcome in the treatment of schizophrenia with classical neuroleptics is in which tail of the assumed normal distribution, a patient′s D2 receptor count falls.
A Theoretical Model for Autism
Authors: Vidal de Caralho Luís Alfred , Ferreira Nívea de Carvalho , Fiszman Adriana
Published: June 2007

Autism is a mental disorder characterized by deficits in socialization, communication, and imagination. Along with the deficits, autistic children may show savant skills (“islets of ability”) of unknown origin that puzzles their families and the psychologists. Comorbidity with epilepsy and mental retardation has brought the researchers′ attention to neurobiological and cognitive theories of the syndrome. The present article proposes a neurobiological model for the autism based on the fundamental biological process of neuronal competition. A neural network capable of defining neural maps—synaptic projections preserving neighborhoods between two neural tissues—simulates the process of neurodevelopment. Experiments were performed reducing the level of neural growth factor released by the neurons, leading to ill‐developed maps and suggesting the cause of the aberrant neurogenesis present in autism. The computer simulations hint that brain regions responsible for the formation of higher level representations are impaired in autistic patients. The lack of this integrated representation of the world would result in the peculiar cognitive deficits of socialization, communication, and imagination and could also explain some “islets of abilities”, like excellent memory for raw data and stimuli discrimination. The neuronal model is based on plausible biological findings and on recently developed cognitive theories of autism. Close relations are established between the computational properties of the neural network model and the cognitive theory of autism denominated “weak central coherence”, bringing some insight to the understanding of the disorder.
Amplitude Suppression and Chaos Control in Epileptic EEG Signals
Authors: Majumdar Kaushik , Myers Mark H.
Published: June 2007

In this paper we have proposed a novel amplitude suppression algorithm for EEG signals collected during epileptic seizure. Then we have proposed a measure of chaoticity for a chaotic signal, which is somewhat similar to measuring sensitive dependence on initial conditions by measuring Lyapunov exponent in a chaotic dynamical system. We have shown that with respect to this measure the amplitude suppression algorithm reduces chaoticity in a chaotic signal (EEG signal is chaotic). We have compared our measure with the estimated largest Lyapunov exponent measure by the largelyap function, which is similar to Wolf′s algorithm. They fit closely for all but one of the cases. How the algorithm can help to improve patient specific dosage titration during vagus nerve stimulation therapy has been outlined.
Spatial Tumor‐Immune Modeling
Authors: de Pillis L. G. , Mallet D. G. , Radunskaya A. E.
Published: June 2007

In this paper, we carry out an examination of four mechanisms that can potentially lead to changing morphologies in a growing tumor: variations in nutrient consumption rates, cellular adhesion, excessive consumption of nutrients by tumor cells and immune cell interactions with the tumor. We present numerical simulations using a hybrid PDE‐cellular automata (CA) model demonstrating the effects of each mechanism before discussing hypotheses about the contribution of each mechanism to morphology change.
Fluid‐Retention Side‐Effects of the Chemotherapy‐Supportive Treatment Interleukin‐11: Mathematical Modelling of Putative Underlying Mechanisms
Authors: Kheifetz Yuri , Elishmereni Moran , Horowitz Smadar , Agur Zvia
Published: June 2007

Interleukin‐11 (IL‐11) is a pleiotropic thrombopoietic cytokine and immune modulator, clinically approved for alleviation of chemotherapy‐induced thrombocytopenia in non‐myeloid malignancies. IL‐11 therapy exerts fluid accumulation‐associated adverse effects, complicating its administration and limiting its use. Implementation of standard biomathematical techniques to assess these effects is not possible, due to incomplete knowledge of the underlying mechanisms. This study investigates IL‐11‐induced blood volume expansion (BVE) by a new mathematical modelling methodology. Alternative models for BVE following IL‐11 therapy were constructed, calibrated with clinical information and simulated in a number of treatment scenarios. The models demonstrated high compliance and were equally capable of reliably predicting BVE in a wide range of treatments, provided sufficient data. Model simulations indicate that frequent and low dose IL‐11 regimens are favored for ensuring minimal fluid retention, upon the current IL‐11 therapy.
Simple Models of Human Locomotion
Authors: Alexander R. McNeill
Published: June 2007

The human body is a complex structure, but our understanding of its movements is greately enhanced by extremely simple mathematical models. A model of walking shows why we have to break into a run at speeds above 3 meters per second, and why the critical speed is lower for children and on the moon. A model of running jumps show why long jumpers run up at a fast sprinting speed, but high jumpers run up much more slowly. Finally, a model od standing jumps explains why athletes can jump higher by using a countermovement than from a static squatting position. The body is represented in these models as a small number of rigid segments connected by hinge joints, powered by muscles with realistic physiological properties.
Chemotherapeutic Effects on Hematopoiesis: A Mathematical Model
Authors: Panetta John Carl
Published: June 2007

Blood cell production is one of the major limiting effects of cell‐cycle‐specific chemotherapy. By studying the effects of the drugs on a mathematical model of hematopoiesis, a better understanding of how to prevent over‐reduction of circulating blood may be investigated.

In this model we will use a delay‐differential equation developed by Mackey and Glass (1977) to show acceptable chemotherapeutic deses (i.e. survival of the circulating blood cells) as a function of: the period which the drugs are administered; the strength of the dose; and the delay from initiation of blood cell production to its release into the blood stream. We then make qualitative comparisons to know effects of cell‐cycle‐specific chemotherapy on circulating blood cell elements. Finally, we also consider how the effects of hematopoietic growth factors alter the outcome of the therapy.
Aftercare for Adolescent Alcohol Use Disorder: Feasibility and Acceptability of a Phone Intervention
Authors: Burleson Joseph A. , Kaminer Yifrah
Published: June 2007

A lack of continuity of care for adolescents with alcohol and other substance use disorders (AOSUD) is common. The objectives of this brief report are to present the rationale for the use of manualized, individual brief therapeutic phone contacts (IBTPC) integrating motivational interviewing and cognitive behavioral therapies for aftercare in youth with AOSUD; and report the results and discuss the implications of a study on the feasibility and acceptability of IBTPC in youths with AOSUD. Four therapists and forty‐three adolescents who completed IBTPC responded to a questionnaire concerning the acceptability, feasibility, and confidentiality of the IBTPC. In general, both subjects and therapists were positively consistent in their endorsement of the common items. In conclusion, aftercare for adolescents with AOSUD utilizing a brief phone intervention is perceived as feasible and acceptable.
Accidental and deliberate overdose among opiate addicts in methadone maintenance treatment: are deliberate overdoses systematically different?
Authors: BEST DAVID , GOSSOP MICHAEL , MAN LAN‐HO , FINCH EMILY , GREENWOOD JUDY , STRANG JOHN
Published: June 2007

The frequency of accidental or deliberate overdose was investigated among 200 opiate addicts in methadone substitution treatment in clinics in Edinburgh and south London. One hundred and three of the participants reported a mean of 3.4 overdoses, with 71 (69%) reporting that their most recent overdose was accidental, 27 (26%) deliberate—the remainder were uncertain. Those whose last overdose was deliberate were more likely to have been prescribed diazepam at that time and were more depressed at the time of interview. Differentiation by self‐reported reason for overdose suggests that treatment providers should distinguish between accidental and deliberate overdose in developing overdose prevention strategies.
Physiological Properties of Rod Photoreceptor Cells in Green-sensitive Cone Pigment Knock-in Mice
Authors: Sakurai Keisuke , Onishi Akishi , Imai Hiroo , Chisaka Osamu , Ueda Yoshiki , Usukura Jiro , Nakatani Kei , Shichida Yoshinori
Published: June 2007

Rod and cone photoreceptor cells that are responsible for scotopic and photopic vision, respectively, exhibit photoresponses different from each other and contain similar phototransduction proteins with distinctive molecular properties. To investigate the contribution of the different molecular properties of visual pigments to the responses of the photoreceptor cells, we have generated knock-in mice in which rod visual pigment (rhodopsin) was replaced with mouse green-sensitive cone visual pigment (mouse green). The mouse green was successfully transported to the rod outer segments, though the expression of mouse green in homozygous retina was ∼11% of rhodopsin in wild-type retina. Single-cell recordings of wild-type and homozygous rods suggested that the flash sensitivity and the single-photon responses from mouse green were three to fourfold lower than those from rhodopsin after correction for the differences in cell volume and levels of several signal transduction proteins. Subsequent measurements using heterozygous rods expressing both mouse green and rhodopsin E122Q mutant, where these pigments in the same rod cells can be selectively irradiated due to their distinctive absorption maxima, clearly showed that the photoresponse of mouse green was threefold lower than that of rhodopsin. Noise analysis indicated that the rate of thermal activations of mouse green was 1.7 × 10−7 s−1, about 860-fold higher than that of rhodopsin. The increase in thermal activation of mouse green relative to that of rhodopsin results in only 4% reduction of rod photosensitivity for bright lights, but would instead be expected to severely affect the visual threshold under dim-light conditions. Therefore, the abilities of rhodopsin to generate a large single photon response and to retain high thermal stability in darkness are factors that have been necessary for the evolution of scotopic vision.
Fitness increases with partner and neighbour allopreening
Authors: Lewis Sue , Roberts Gilbert , Harris Mike P , Prigmore Carina , Wanless Sarah
Published: June 2007

Altruism and selfishness are fundamental characteristics of human and animal societies. Among colonial biparental species, breeding outcome depends on interactions between mates and neighbours. However, the relationships between cooperation within and among partnerships and fitness have not been fully investigated. We show that in the highly colonial common guillemot (Uria aalge), altruistic behaviour (allopreening) towards a mate was positively related to long-term fitness, whereas allopreening a neighbour was related to current fitness. Turnover is much lower within than between pairs, so our results suggest that allopreening within pairs generates fitness returns at longer timescales than between pairs. Allopreening not only removes ectoparasites and maintains plumage condition, but may also have important social functions. We found a negative relationship between fight rate and allopreen rate between breeding neighbours, with nests exhibiting low breeding success having a higher frequency of fights with neighbours. We also found evidence for reciprocity in allopreening. Thus, allopreening may function as a reciprocal stress reducer, to decrease the likelihood of fights and associated breeding failure. We suggest that altruistic behaviour has long-term benefits for the survival of the offspring when living in a crowded neighbourhood.
The interfacial structure and Young's modulus of peptide films having switchable mechanical properties
Authors: Middelberg A.P.J , He L , Dexter A.F , Shen H.-H , Holt S.A , Thomas R.K
Published: June 2007

We report the structure and Young's modulus of switchable films formed by peptide self-assembly at the air–water interface. Peptide surfactant AM1 forms an interfacial film that can be switched, reversibly, from a high- to low-elasticity state, with rapid loss of emulsion and foam stability. Using neutron reflectometry, we find that the AM1 film comprises a thin (approx. 15 Å) layer of ordered peptide in both states, confirming that it is possible to drastically alter the mechanical properties of an interfacial ensemble without significantly altering its concentration or macromolecular organization. We also report the first experimentally determined Young's modulus of a peptide film self-assembled at the air–water interface (
E
=80 MPa for AM1, switching to
E
<20 MPa). These findings suggest a fundamental link between
E
and the macroscopic stability of peptide-containing foam. Finally, we report studies of a designed peptide surfactant, Lac21E, which we find forms a stronger switchable film than AM1 (
E
=335 MPa switching to
E
<4 MPa). In contrast to AM1, Lac21E switching is caused by peptide dissociation from the interface (i.e. by self-disassembly). This research confirms that small changes in molecular design can lead to similar macroscopic behaviour via surprisingly different mechanisms.
Boundary tracing and boundary value problems: II. Applications
Authors: Anderson Michael L , Bassom Andrew P , Fowkes Neville
Published: June 2007

This is the second of a pair of papers describing the use of boundary tracing for boundary value problems. In the preceding article, the theory of the technique was explained and it was shown how it enables one to use known exact solutions of partial differential equations to generate new solutions. Here, we illustrate the use of the technique by applying it to three equations of practical significance: Helmholtz's equation, Poisson's equation and the nonlinear constant mean curvature equation. A variety of new solutions are obtained and the potential of the technique for further application outlined.
Rhesus monkeys correctly read the goal-relevant gestures of a human agent
Authors: Hauser Marc D , Glynn David , Wood Justin
Published: June 2007

When humans point, they reveal to others their underlying intent to communicate about some distant goal. A controversy has recently emerged based on a broad set of comparative and phylogenetically relevant data. In particular, whereas chimpanzees (
Pan troglodytes
) have difficulty in using human-generated communicative gestures and actions such as pointing and placing symbolic markers to find hidden rewards, domesticated dogs (
Canis familiaris
) and silver foxes (
Urocyon cinereoargenteus
) readily use such gestures and markers. These comparative data have led to the hypothesis that the capacity to infer communicative intent in dogs and foxes has evolved as a result of human domestication. Though this hypothesis has met with challenges, due in part to studies of non-domesticated, non-primate animals, there remains the fundamental question of why our closest living relatives, the chimpanzees, together with other non-human primates, generally fail to make inferences about a target goal of an agent's communicative intent. Here, we add an important wrinkle to this phylogenetic pattern by showing that free-ranging rhesus monkeys (
Macaca mulatta
) draw correct inferences about the goals of a human agent, using a suite of communicative gestures to locate previously concealed food. Though domestication and human enculturation may play a significant role in tuning up the capacity to infer intentions from communicative gestures, these factors are not necessary.
Streptococcus orisuis sp. nov., isolated from the pig oral cavity
Authors: Takada Kazuko , Hirasawa Masatomo
Published: June 2007

Five bacterial strains, designated as NUM 1001T, NUM 1002, NUM 1003, NUM 1004 and NUM 1005, were isolated from the oral cavities of pigs. Colonies grown on mitis salivarius agar were similar in morphology to those of mutans streptococci. The novel isolates were analysed biochemically using the Rapid ID 32 Strep microsystem, subjected to DNA–DNA hybridization with oral streptococci and had their 16S rRNA genes sequenced. On the basis of the phylogenetic and phenotypic evidence obtained, the strains represent a novel species of the genus Streptococcus, for which the name Streptococcus orisuis sp. nov. is proposed. The type strain is NUM 1001T (=JCM 14035T=DSM 18307T).
Dyadobacter koreensis sp. nov., isolated from fresh water
Authors: Baik Keun Sik , Kim Mi Sun , Kim Eun Mi , Kim Hyung Rak , Seong Chi Nam
Published: June 2007

A non-motile, rod-shaped, light-yellow-pigmented bacterium, designated strain WPCB159T, was isolated from freshwater samples collected from the Woopo wetland in Korea. The cells were Gram-negative, aerobic and catalase- and oxidase-positive. The major fatty acids were C16 : 1
ω7c (34.8 %), iso-C15 : 0 (24.2 %) and C16 : 0 (9.4 %). The DNA G+C content was 44 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain WPCB159T forms a lineage within the genus Dyadobacter (family ‘Flexibacteraceae’) and is closely related to Dyadobacter hamtensis HHS 11T (97.8 % sequence similarity) and to other members of the genus Dyadobacter (95.2–96.8 % sequence similarity). The phenotypic characteristics and DNA–DNA hybridization relatedness data indicate that strain WPCB159T should be distinguished from D. hamtensis HHS 11T. On the basis of the evidence presented in this study, strain WPCB159T represents a novel species of the genus Dyadobacter, for which the name Dyadobacter koreensis sp. nov. is proposed. The type strain is WPCB159T (=KCTC 12537T=NBRC 101116T).
The invected gene of Drosophila: sequence analysis and expression studies reveal a close kinship to the engrailed gene.
Authors: Coleman K G , Poole S J , Weir M P , Soeller W C , Kornberg T
Published: June 2007

The invected and engrailed genes are juxtaposed in the Drosophila genome and are closely related in sequence and pattern of expression. The structure of the most abundant invected transcript was defined by obtaining the full-length cDNA sequence and by S1 nuclease sensitivity and primer extension studies; a partial sequence of the invected gene was determined; and the developmental profile of invected expression was characterized by Northern analysis and by in situ localization. The invected gene, like the engrailed gene, is expressed in the embryonic and larval cells of the posterior developmental compartments and in the embryonic hindgut, clypeolabrum, and nervous system. Like the engrailed gene, the invected gene can encode a protein of approximately 60 kD that contains a homeo box near its carboxyl terminus; indeed, a sequence of 117 amino acids in the carboxy-terminal region of both proteins is almost identical. The developmental role of the invected gene is not known.
Induction of the heat shock response of E. coli through stabilization of sigma 32 by the phage lambda cIII protein.
Authors: Bahl H , Echols H , Straus D B , Court D , Crowl R , Georgopoulos C P
Published: June 2007

The cIII protein of phage lambda favors the lysogenic response to infection by inhibiting the degradation of the lambda cII protein, which exerts the primary control on the developmental decision for lysis or lysogeny. To study the mechanism and scope of cIII-mediated regulation, we have used plasmid systems to examine the specific effect of cIII overproduction on the growth of Escherichia coli and the synthesis of bacterial proteins. We have found that maximal production of cIII prolongs the heat-induced synthesis of E. coli heat shock proteins and provokes elevated production of heat shock proteins even at low temperature. The overproduction of heat shock proteins is correlated with a rapid inhibition of cell growth, as judged by measurements of optical density. We suggest that an overactive heat shock response inhibits bacterial growth, either because excessive production of one or more of the proteins is highly deleterious or because only heat shock promoters are transcribed efficiently. To examine the effect of cIII on sigma 32, the specificity factor for the heat shock response, we have studied the stability of sigma 32 in cells carrying both cIII- and sigma 32-producing plasmids; the half-life of sigma 32 is increased fourfold in the presence of cIII. We conclude that overproduction of cIII provokes the heat shock response by increasing the steady-state level of active sigma 32. These studies also support the concept that the rate of expression of heat shock proteins is directly correlated with the amount of active sigma 32 and that regulation of the stability of sigma 32 may be an important factor for control of the heat shock response.
Alternative processing during development of a macronuclear chromosome family in Oxytricha fallax.
Authors: Herrick G , Hunter D , Williams K , Kotter K
Published: June 2007

Macronuclear chromosomes in Oxytricha fallax, a hypotrichous ciliate, are very short. They often belong to small families of cross-hybridizing chromosomes of two or three different sizes. For example, the 81-MAC family consists of three sizes of macronuclear chromosomes (4.9, 2.9, and 1.6 kbp) (Cartinhour and Herrick 1984). We show that the family actually consists of two closely related sets of three each and that the two sets are independently created by alternative processing of two separate precursor (micronuclear) versions. Chromosomes of a set share a common 1.6-kbp region, which contains a transcribed gene coding for a 25-kD protein. Different-sized macronuclear chromosomes of a set result from alternative choices of positions for telomere formation. All six members of the family are reproducibly generated in each developing macronucleus, and their copy numbers are stably maintained during vegetative replication of the macronucleus (Herrick et al. 1987). Here we argue for the existence of three distinct copy control elements in the 81-MAC family chromosomes. A model is discussed in which, following polytenization of the micronuclear chromosomes, different chromatids are processed differently, and, subsequently, replication-competent macronuclear chromosome products are amplified under the influence of the vegetative copy control elements.
The mother-daughter mating type switching asymmetry of budding yeast is not conferred by the segregation of parental HO gene DNA strands.
Authors: Klar A J
Published: June 2007

The Saccharomyces cerevisiae HO gene, which encodes a site-specific endonuclease, is transcribed in the parent (mother) cell but not in the daughter (bud) cell. Consequently mother cells can switch their mating type whereas bud cells cannot. Whether or not the different capabilities of these cells are due to a nonrandom segregation of parental HO gene DNA strands to progeny cells is tested here by assaying the pattern of switching in cells where the HO gene is inverted in the chromosome. In an inverted HO strain, as is the case with the normal HO arrangement strains, only the mother cells were found to switch. Thus, the possibility of asymmetric segregation of parental HO gene DNA strands does not regulate the mother-daughter asymmetry of switching.
Establishment and refinement of segmental pattern in the Drosophila embryo: spatial control of engrailed expression by pair-rule genes.
Authors: DiNardo S , O'Farrell P H
Published: June 2007

We are examining the development of the segmental body pattern of Drosophila by immunolocalization of engrailed, a developmental regulatory protein that maintains segmental subdivisions in the embryo, and is expressed in a spatially restricted (striped) manner that persists while the body pattern is being established and refined. A regulatory network among pair-rule segmentation genes establishes the striped pattern of engrailed expression. In general, mutations in particular pair-rule genes affect either even- or odd-numbered engrailed stripes. For example, fushi tarazu or odd-paired mutations delete even-numbered stripes, whereas paired mutations delete odd-numbered stripes. An analysis of engrailed expression in other mutants, including even-skipped odd-skipped double mutants, indicates that some pair-rule genes play a rule in establishing the correct width and position of engrailed stripes. Overall, the changes in engrailed pattern have consequences for final embryonic body pattern. Thus, the pair-rule loci, acting through engrailed, establish an early, general outline of body pattern. However, in several pair-rule mutants, engrailed patterns are dynamic, suggesting that as later events build upon this general rule to form the final body pattern, adjustments are made in response to the earlier pair-rule defect--that is, the pattern regulates.