bluuebunny/crossref_metadata_2025 huggingface dataset:
The Evf-2 noncoding RNA is transcribed from the Dlx-5/6 ultraconserved region and functions as a Dlx-2 transcriptional coactivator
Authors: Feng Jianchi , Bi Chunming , Clark Brian S. , Mady Rina , Shah Palak , Kohtz Jhumku D.
Published: May 2006

The identification of ultraconserved noncoding sequences in vertebrates has been associated with developmental regulators and DNA-binding proteins. One of the first of these was identified in the intergenic region between the Dlx-5 and Dlx-6 genes, members of the Dlx/dll homeodomain-containing protein family. In previous experiments, we showed that Sonic hedgehog treatment of forebrain neural explants results in the activation of Dlx-2 and the novel noncoding RNA (ncRNA), Evf-1. In this report, we show that the Dlx-5/6 ultraconserved region is transcribed to generate an alternatively spliced form of Evf-1, the ncRNA Evf-2. Evf-2 specifically cooperates with Dlx-2 to increase the transcriptional activity of the Dlx-5/6 enhancer in a target and homeodomain-specific manner. A stable complex containing the Evf-2 ncRNA and the Dlx-2 protein forms in vivo, suggesting that the Evf-2 ncRNA activates transcriptional activity by directly influencing Dlx-2 activity. These experiments identify a novel mechanism whereby transcription is controlled by the cooperative actions of an ncRNA and a homeodomain protein. The possibility that a subset of vertebrate ultraconserved regions may function at both the DNA and RNA level to control key developmental regulators may explain why ultraconserved sequences exhibit 90% or more conservation even after 450 million years of vertebrate evolution.
The locus control region is required for association of the murine β-globin locus with engaged transcription factories during erythroid maturation
Authors: Ragoczy Tobias , Bender M.A. , Telling Agnes , Byron Rachel , Groudine Mark
Published: May 2006

We have examined the relationship between nuclear localization and transcriptional activity of the endogenous murine β-globin locus during erythroid differentiation. Murine fetal liver cells were separated into distinct erythroid maturation stages by fluorescence-activated cell sorting, and the nuclear position of the locus was determined at each stage. We find that the β-globin locus progressively moves away from the nuclear periphery with increasing maturation. Contrary to the prevailing notion that the nuclear periphery is a repressive compartment in mammalian cells, βmajor-globin expression begins at the nuclear periphery prior to relocalization. However, relocation of the locus to the nuclear interior with maturation is accompanied by an increase in βmajor-globin transcription. The distribution of nuclear polymerase II (Pol II) foci also changes with erythroid differentiation: Transcription factories decrease in number and contract toward the nuclear interior. Moreover, both efficient relocalization of the β-globin locus from the periphery and its association with hyperphosphorylated Pol II transcription factories require the locus control region (LCR). These results suggest that the LCR-dependent association of the β-globin locus with transcriptionally engaged Pol II foci provides the driving force for relocalization of the locus toward the nuclear interior during erythroid maturation.
p27kip1 independently promotes neuronal differentiation and migration in the cerebral cortex
Authors: Nguyen Laurent , Besson Arnaud , Heng Julian Ik-Tsen , Schuurmans Carol , Teboul Lydia , Parras Carlos , Philpott Anna , Roberts James M. , Guillemot François
Published: May 2006

The generation of neurons by progenitor cells involves the tight coordination of multiple cellular activities, including cell cycle exit, initiation of neuronal differentiation, and cell migration. The mechanisms that integrate these different events into a coherent developmental program are not well understood. Here we show that the cyclin-dependent kinase inhibitor p27Kip1 plays an important role in neurogenesis in the mouse cerebral cortex by promoting the differentiation and radial migration of cortical projection neurons. Importantly, these two functions of p27Kip1 involve distinct activities, which are independent of its role in cell cycle regulation. p27Kip1 promotes neuronal differentiation by stabilizing Neurogenin2 protein, an activity carried by the N-terminal half of the protein. p27Kip1 promotes neuronal migration by blocking RhoA signaling, an activity that resides in its C-terminal half. Thus, p27Kip1 plays a key role in cortical development, acting as a modular protein that independently regulates and couples multiple cellular pathways contributing to neurogenesis.
The characteristics of LTP induced in hippocampal slices are dependent on slice-recovery conditions
Authors: Capron Brigitte , Sindic Christian , Godaux Emile , Ris Laurence
Published: May 2006

In area CA1 of hippocampal slices which are allowed to recover from slicing “in interface” and where recordings are carried out in interface, a single 1-sec train of 100-Hz stimulation triggers a short-lasting long-term potentiation (S-LTP), which lasts 1–2 h, whereas multiple 1-sec trains induce a long-lasting LTP (L-LTP), which lasts several hours. Moreover, the threshold and the features of these LTP depend on the history of the neurons, a phenomenon known as metaplasticity. Here, where all recordings were performed in interface, we found that allowing the slices to recover “in submersion” had dramatic metaplastic effects. In these conditions, a single 1-sec train at 100 Hz induced an L-LTP which lasted at least 4 h and was dependent on protein synthesis. Interestingly, this type of metaplasticity was observed when the concentration of Mg++ used was 1.0 mM but not when it was 1.3 mM. The LTP induced by four 1-sec trains at 100 Hz was similar whatever the incubation method. However, the signaling cascades recruited to achieve that pattern were different. In the interface–interface paradigm (recovery and recording both in interface) the four-train induced LTP recruited the PKA signaling pathway but not that of the p42/44MAPK. On the contrary, in the submersion–interface paradigm the four-train induced LTP recruited the p42/44MAPK signaling pathway but not that of the PKA. To our knowledge this is the first example of metaplasticity involving the recruitment of signaling cascades in LTP.
Place learning in the Morris water task: Making the memory stick
Authors: Bolding Kevin , Rudy Jerry W.
Published: May 2006

Although the Morris water task has been used in hundreds of studies of place learning, there have been no systematic studies of retention of the place memory. We report that retention, as measured by selective search behavior on a probe trial, is excellent when the retention interval is short (5–10 min). However, performance rapidly deteriorates, so that by ∼4 h the search is no longer selective. Additional experiments revealed that selective search at longer retention intervals was improved by inserting gaps between blocks of training trials, but this effect was a non-monotonic function of the interval separating trial blocks. Our experiments also revealed that the location of the first block of trials (Room A or Room B) was irrelevant to long-term retention. A memory modulation theoretical framework may provide a useful way to understand these findings.
Foreground contextual fear memory consolidation requires two independent phases of hippocampal ERK/CREB activation
Authors: Trifilieff Pierre , Herry Cyril , Vanhoutte Peter , Caboche Jocelyne , Desmedt Aline , Riedel Gernot , Mons Nicole , Micheau Jacques
Published: May 2006

Fear conditioning is a popular model for investigating physiological and cellular mechanisms of memory formation. In this paradigm, a footshock is either systematically associated to a tone (paired conditioning) or is pseudorandomly distributed (unpaired conditioning). In the former procedure, the tone/shock association is acquired, whereas in the latter procedure, the context/shock association will prevail. Animals with chronically implanted recording electrodes show enhanced amplitude of the extracellularly recorded field EPSP in CA1 pyramidal cells for up to 24 h after unpaired, but not paired, fear conditioning. This is paralleled by a differential activation of the ERK/CREB pathway in CA1, which is monophasic in paired conditioning (0–15 min post-conditioning), but biphasic (0–1 h and 9–12 h post-conditioning) in unpaired conditioning as revealed by immunocytochemistry and Western blotting. Intrahippocampal injection of the MEK inhibitor U0126 prior to each phase prevents the activation of both ERK1/2 and CREB after unpaired conditioning. Block of any activation phase leads to memory impairment. We finally reveal that the biphasic activation of ERK/CREB activity is independently regulated, yet both phases are critically required for the consolidation of long-term memories following unpaired fear conditioning. These data provide compelling evidence that CA1 serves different forms of memory by expressing differential cellular mechanisms that are dependent on the training regime.
Do rats use shape to solve “shape discriminations”?
Authors: Minini Loredana , Jeffery Kathryn J.
Published: May 2006

Visual discrimination tasks are increasingly used to explore the neurobiology of vision in rodents, but it remains unclear how the animals solve these tasks: Do they process shapes holistically, or by using low-level features such as luminance and angle acuity? In the present study we found that when discriminating triangles from squares, rats did not use shape but instead relied on local luminance differences in the lower hemifield. A second experiment prevented this strategy by using stimuli—squares and rectangles—that varied in size and location, and for which the only constant predictor of reward was aspect ratio (ratio of height to width: a simple descriptor of “shape”). Rats eventually learned to use aspect ratio but only when no other discriminand was available, and performance remained very poor even at asymptote. These results suggest that although rats can process both dimensions simultaneously, they do not naturally solve shape discrimination tasks this way. This may reflect either a failure to visually process global shape information or a failure to discover shape as the discriminative stimulus in a simultaneous discrimination. Either way, our results suggest that simultaneous shape discrimination is not a good task for studies of visual perception in rodents.
Motivated Gaze
Authors: Isaacowitz Derek M.
Published: May 2006

How does gaze relate to psychological properties of the gazer? Studies using eye tracking reveal robust group differences in gaze toward emotional information: Optimists gaze less at negative, unpleasant images than do pessimists, and older individuals look away from negative faces and toward happy faces. These group differences appear to reflect an underlying motivation to achieve and maintain good moods by directing attention to mood-facilitating stimuli. Maintaining a positive mood is only one goal-related context that influences visual attention; recent work has also suggested that other goal states can impact gaze. Gaze therefore is a tool of motivation, directing gazers toward stimuli that are consistent with their goals and away from information that will not facilitate goal achievement.
Empirical and Theoretical Conclusions of an Analysis of Outcomes of HIV-Prevention Interventions
Authors: Albarracín Dolores , Durantini Marta R. , Earl Allison
Published: May 2006

Over two decades of HIV-prevention attempts have generated a most impressive ecological data set for the test of behavioral-change and persuasion theories in the domain of condom use. An analysis of this evidence has yielded five important empirical and theoretical conclusions. First, interventions are more successful at achieving immediate knowledge and motivational change than they are at achieving immediate behavioral change. Second, the immediate motivational change decays over time, whereas behavior change increases over the same period. Third, interventions that engage audiences in particular activities, such as role-playing condom use, are more effective than presentations of materials to passive audiences. Fourth, interventions consistent with the theories of reasoned action and planned behavior, with self-efficacy models, and with information-motivation and behavioral-skills models prove effective, whereas interventions designed to induce fear do not. Fifth, expert intervention facilitators are more effective than lay community members in almost all cases. When populations are unempowered, expert facilitators are particularly effective, and they are most effective if they also share the gender and ethnicity of the target audience.
Psychobiological Roots of Early Attachment
Authors: Hofer Myron A.
Published: May 2006

New laboratory research has revealed a network of simple behavioral, physiological, and neural processes that underlie the psychological constructs of attachment theory. It has become apparent that the unique features of early infant attachment reflect certain unique features of early infant sensory and motor integration, learning, communication, and motivation, as well as the regulation of biobehavioral systems by the mother–infant interaction. In this article, I will use this new knowledge to answer three major questions that have remained unsettled in our understanding of early human attachment: What creates an attachment bond? Why is early maternal separation stressful? How can early relationships have lasting effects? I will discuss the implications of these new answers for human infants and for the development of mental processes. Attachment remains useful as a concept that, like hunger, describes the operation of subprocesses that work together within the frame of a vital biological function.
Children's Perceptions of Families: What Do They Really Think?
Authors: Rigg Andrea , Pryor Jan
Published: May 2006

The perceptions of 111 New Zealand children from different family structures and cultures were examined. Lone‐parent families, blended families, extended family, non‐residential parents and couples with children were highly endorsed. No great distinctions were made between married and cohabiting couples when the relationship included children. Definitions of family frequently mentioned affective factors. In comparing ethnic groups and family structures some differences were noted, but in general children have many similarities in their family concepts. Comparisons with a recent study of adolescents did not reveal clear‐cut developmental sequences in young people's perceptions. Overall, an inclusive and realistic view of families was expressed. © 2006 The Author(s) Journal compilation © 2006 National Children's Bureau.
Nitridation of High‐Purity Silicon
Authors: ATKINSON A. , MOULSON A. J. , ROBERTS E. W.
Published: May 2006

The kinetics and morphology of the growth of nitride on spec‐trographically pure Si were investigated in the range 1250° to 1370°C for N2 pressures of 20 to 760 torr. A model is presented which explains all the observations. The initial linear kinetics are associated with the growth of individual nitride nuclei. As the nuclei coalesce, the reaction rate steadily decreases, finally falling effectively to zero when the Si is completely covered with nitride. The model indicates how the microstructure of reaction‐sintered Si3N4 may be controlled.
Tracer Concentration Gradients for Diffusion Coefficients Exponentially Dependent on Concentration
Authors: WEI G. C. T. , WUENSCH B. J.
Published: May 2006

A diffusion equation having a tracer diffusion coefficient exponentially dependent on solute concentration,D*=D0*exp (βC), was solved numerically for thin‐film and thick‐film boundary conditions and varying values of annealing time, film thickness, and β. For values of β in the range 3 to 10 mol fraction−1, the calculated distribution of solute remained remarkably Gaussian. The apparent diffusion coefficient evaluated from such solute gradients was greater than the true tracer diffusion coefficientD0* by ≤20% for large β and shallow tracer penetration. The results were used to estimate possible errors in data which have been reported for several oxide systems, and may be used as a guide for the selection of experimental parameters so that corrections will not be necessary.
Tritium Balance in High‐Temperature Gas‐Cooled Reactors
Authors: RÖHRIG H. D. , FISCHER P. G. , HECKER R.
Published: May 2006

In high‐temperature gas‐cooled reactors, tritium produced by fission is, for the most part, retained in the coated particle fuel, but 3He‐ and 6Li‐originated tritium takes part in a complex system of sorption, diffusion, and exchange reactions in the core graphite. Permeation through the heat‐exchanger tube walls leads to secondary circuit contamination. It was found that tritium is very soluble in graphite and that permeation is significantly reduced by oxide layers on metal surfaces.
Glass‐Metal Reaction in AC Electric Field
Authors: KIM CHULHO , TOMOZAWA MINORU
Published: May 2006

Reactions between glasses and metal electrodes (Ag and Au) in an ac electric field were investigated. Under a constant electric current, the extent of reaction caused by an electric field increased rapidly with time initially, then reached a constant value. In a constant time, the reaction increased with increasing current density and decreased with increasing frequency. These phenomena were explained qualitatively on the basis of the increased concentration of metal ions in the glass caused by the space‐charge electric field.
Effect of Microstructure on Rate of Machining of Ceramics
Authors: RICE ROY W. , SPERONELLO BARRY K.
Published: May 2006

The effect of microstructure on the machinability of a variety of ceramics was studied. The machining difficulty, i.e. the inverse of sawing or grinding rate at constant force, increased with decreasing porosity and grain size. For materials with nonuniform distributions of grain size or porosity, machining rates were controlled by the smaller grains and the least porous regions. The grain‐size dependence of the machining difficulty was generally greater for harder materials. The effect of porosity on machining difficulty generally followed the same trend as its effect on other mechanical properties. The results obtained were interpreted in terms of the Petch relation, which provided a rationale for the occurrence of flaw sizes independent of grain size. The results also indicate that theories of the machinability of ceramics must include the effects of compressive strength and, especially, hardness.
Kinetic Studies on the Precipitation of Hematite from Iron‐Rich Spinel Solid Solutions
Authors: YAMAGUCHI TAKASHI , KIMURA TOSHIO
Published: May 2006

The kinetics of hematite precipitation from iron‐rich spinel solid solutions has been studied with special emphasis on the effect of divalent cations and iron‐oxide concentration. The precipitation kinetics is expressed by the Avrami equation α= 1 – exp [–k(t –t0)n] with n= 1, where α, k, and t are fractional precipitation, proportionality constant, and time, respectively. The process is characterized by an activation energy of 30·0.5 kcal/mol, independent of iron‐oxide concentration. Stabilization of spinel solid solutions by the cation is most pronounced for Ni followed by Mg and Zn in the order stated, and the effect of the cation is interpreted in terms of the cation distribution in the spinel lattice.
Improved Estimates of Correlation Coefficients and their Impact on Optimum Portfolios
Authors: Elton Edwin J. , Gruber Martin J. , Spitzer Jonathan
Published: May 2006

To implement mean variance analysis one needs a technique for forecasting correlation coefficients. In this article we investigate the ability of several techniques to forecast correlation coefficients between securities. We find that separately forecasting the average level of pair‐wise correlations and individual pair‐wise differences from the average improves forecasting accuracy. Furthermore, forming homogenous groups of firms on the basis of industry membership or firm attributes (e.g. size) improves forecast accuracy. Accuracy is evaluated in two ways: First, in terms of the error in estimating future correlation coefficients. Second, in the characteristics of portfolios formed on the basis of each forecasting technique. The ranking of forecasting techniques is robust across both methods of evaluation and the better techniques outperform prior suggestions in the literature of financial economics.
African matrilineages in American Creole cattle: evidence of two independent continental sources
Authors: Lirón J. P. , Bravi C. M. , Mirol P. M. , Peral‐García P. , Giovambattista G.
Published: May 2006

In order to clarify the historical origin and phylogeographic affinities of Creole cattle matrilineages throughout the American continent, we analysed published D‐loop mtDNA sequences (n = 454) from Creole, Iberian and African cattle breeds. The Western European T3 haplogroup was the most common in American Creole cattle (63.6%), followed by the African T1 (32.4%) and the Near Eastern T2 haplogroups (4%). None of the sequences were found in Bos indicus types. Within the African T1 haplogroup there were two subclades, T1a and T1*, whose geographic distribution in America was clearly disjointed. T1a is a highly divergent clade originally reported for Creole cattle from Brazil and the Lesser Antilles, but whose geographic distribution in Africa remains unknown. In contrast, lineages attributable to T1* are restricted in America to the region colonized by the Spaniards. We propose a new hypothesis for the origins of Creole cattle that summarizes all previously published historical and genetic data. While the African T1* fraction in Creole cattle may have arrived in America through the Iberian breeds, the divergent T1a lineages may have been introduced by Portuguese and other European crowns from some unknown, not‐yet‐sampled African location. Additional molecular studies will be required for pinpointing the specific African regional source.
Channel catfish BAC‐end sequences for marker development and assessment of syntenic conservation with other fish species
Authors: Xu P. , Wang S. , Liu L. , Peatman E. , Somridhivej B. , Thimmapuram J. , Gong G. , Liu Z.
Published: May 2006

In the present study, 25 195 BAC ends for channel catfish (Ictalurus punctatus) were sequenced, generating 20 366 clean BAC‐end sequences (BES), with an average read length of 557 bp after trimming. A total of 11 414 601 bp were generated, representing approximately 1.2% of the catfish genome. Based on this survey, the catfish genome was found to be highly AT‐rich, with 60.7% A+T and 39.3% G+C. Approximately 12% of the catfish genome consisted of dispersed repetitive elements, with the Tc1/mariner transposons making up the largest percentage by base pair (4.57%). Microsatellites were detected in 17.5% of BES. Catfish BACs were anchored to the zebrafish and Tetraodon genome sequences by BLASTN, generating 16% and 8.2% significant hits (E < e−5) respectively. A total of 1074 and 773 significant hits were unique to the zebrafish and Tetraodon genomes, respectively, of which 417 and 406, respectively, were identified as known genes in other species, providing a major genome resource for comparative genomic mapping.
Vertical partitioning of CO2 production within a temperate forest soil
Authors: DAVIDSON ERIC A. , SAVAGE KATHLEEN E. , TRUMBORE SUSAN E. , BORKEN WERNER
Published: May 2006

The major driving factors of soil CO2 production – substrate supply, temperature, and water content – vary vertically within the soil profile, with the greatest temporal variations of these factors usually near the soil surface. Several studies have demonstrated that wetting and drying of the organic horizon contributes to temporal variation in summertime soil CO2 efflux in forests, but this contribution is difficult to quantify. The objectives of this study were to partition CO2 production vertically in a mixed hardwood stand of the Harvard Forest, Massachusetts, USA, and then to use that partitioning to evaluate how the relative contributions of CO2 production by genetic soil horizon vary seasonally and interannually. We measured surface CO2 efflux and vertical soil profiles of CO2 concentration, temperature, water content, and soil physical characteristics. These data were applied to a model of effective diffusivity to estimate CO2 flux at the top of each genetic soil horizon and the production within each horizon. A sensitivity analysis revealed sources of uncertainty when applying a diffusivity model to a rocky soil with large spatial heterogeneity, especially estimates of bulk density and volumetric water content and matching measurements of profiles and surface fluxes. We conservatively estimate that the O horizon contributed 40–48% of the total annual soil CO2 efflux. Although the temperature sensitivity of CO2 production varied across soil horizons, the partitioning of CO2 production by horizon did not improve the overall prediction of surface CO2 effluxes based on temperature functions. However, vertical partitioning revealed that water content covaried with CO2 production only in the O horizon. Large interannual variations in estimates of O horizon CO2 production indicate that this layer could be an important transient interannual source or sink of ecosystem C.
14C – a tool for separation of autotrophic and heterotrophic soil respiration
Authors: HAHN VOLKER , HÖGBERG PETER , BUCHMANN NINA
Published: May 2006

We assessed the potential of using 14C contents of soil respired CO2 to calculate the contributions of heterotrophic and autotrophic respiration to total soil respiration. The partitioning of these fluxes is of utmost importance to evaluate implications of environmental change on soil carbon cycling and sequestration. At three girdled forest stands in Sweden and Germany, where the tree root (autotrophic) respiration had been eliminated, we measured both flux rates and 14C contents of soil respired CO2 in girdled and control plots in the summers of 2001 or 2002. At all stands, CO2 flux rates were slightly higher in the control plots, whereas the 14C contents of respired CO2 tended to be higher in the girdled plots. This was expected and confirmed that heterotrophically respired CO2 cycles more slowly through the forest ecosystem than autotrophically respired CO2. On the basis of these data, the contributions of hetero‐ and autotrophic respiration to total soil respiration were calculated using two separate approaches (i.e. based on flux rates or 14C). Fractions of heterotrophic respiration ranged from 53% to 87%. Values calculated by both approaches did not differ significantly from each other. Finally, we compared the 14C contents of soil respired CO2 in the girdled plots with the 14C contents of heterotrophically respired CO2 calculated by three different 14C models. None of the models matched the measured data sufficiently. In addition, we suspect that inherent effects of girdling may cause the 14C content of CO2 respired in the girdled plots to be lower than ‘true’ heterotrophically respired CO2 in an undisturbed plot. Nevertheless, we argue that measurements and modeling of 14C can be developed into a valuable tool for separating heterotrophic and autotrophic soil respiration (e.g. when girdling cannot be performed).
Are non‐pharmacological nursing interventions for the management of pain effective?— A meta‐analysis*
Authors: Sindhu Fahera
Published: May 2006

A meta‐analysis of randomized controlled trials (RCTs) assessing the effectiveness of a non‐pharmacological intervention on the management of pain was conducted Forty‐nine relevant primary studies were identified and retrieved Individual mean pain scores from these studies were converted to standardized effect sizes and meta‐analyses were conducted Although there is evidence, in the form of primary studies, to suggest that non‐pharmacological nursing interventions are effective in the management of pain, the 49 studies, pooled in this meta‐analysis, were too heterogeneous to detect a difference between the treatment and control groups reliably There is a need to rigorously test these interventions in the form of primary RCTs
Mental health intensive care: the nurses'experience and perceptions of a new unit
Authors: Gentle Jan
Published: May 2006

This paper describes a qualitative research study which explored the practices and views of nurses working on a new Mental Health Intensive Care Unit A review of the literature identified the main aspects of intensive care provision (1) physical security, (2) characteristics of the patient group, (3) staff‐patient ratios, (4) therapeutic environment and (5) multi‐agency involvement Twenty‐one periods of participant observation helped form the questions for a semi structured in‐depth tape recorded interview in which 11 out of a total of 16 trained nurses took part The information is categorized and the discussion is informed by observation of practice The nurses perceived the following as the main issues that the physical environment is inadequate for security, that the patient group appears to have the common characteristic of being unwanted in other clinical settings, that the staff‐patient ratio is inadequate and that their vision of the nature of a therapeutic environment is vague
Knowledge, skills and experiences for community health nursing practice: the perceptions of community nurses, administrators and educators
Authors: Bramadat Ina J , Andrusyszyn Mary Anne , Chalmers Karen
Published: May 2006

Nursing in Canada is committed to preparing all new graduates at the baccalaureate level for entry to nursing practice by the year 2000 This goal has major implications for community health nursing education and practice Health care reform is also expected to move care out of the hospital and into the community It was against this backdrop that the researchers mounted a study on the educational preparation needed for graduates to begin to practice community health nursing In this paper, the knowledge, professional and personal skills, and experiences that graduates need to begin community practice are reported The study was carried out within an action‐research framework All major groups of stakeholders involved in community health nursing throughout the study province were involved in the project This included nurses and administrators from two public health agencies (provincial and municipal), home care nurses, home health nurses (l e non‐governmental visiting nurses), community health centres, provincial health care and nursing consultants, and faculty from two universities In addition to the generation of relevant research findings for use by the educational institutions, the study was initiated to set the stage for future and ongoing interactions between the researchers and community experts to implement the findings from the project Data were collected from 118 participants by means of 27 focus groups of community nurses, administrators and educators Interviews were tape‐recorded transcribed and analysed using latent content analysis and constant comparison techniques Findings indicated that qualified nurses from university programmes need a wide range of knowledge, skills and experiences to begin to practice community health nursing Detailed accounts of these requirements are outlined and the implications for practice and education put forward
The clinical nurse manager: a literature review
Authors: Oroviogoicoechea Cristina
Published: May 2006

This paper is a literature review of the clinical nurse manager role The purpose is to identify, m today's health care environment, what expectations organizations in this role have, and therefore to determine the skills and characteristics required to be effective at this level An analysis of the literature revealed a consensus that human and leadership skills are taking the place of clinical skills It is suggested that within them decision‐making is the key factor in responding to the changing and competitive health care environment
Nursing students' perceptions of difficult or challenging clinical situations
Authors: Cooke Marie
Published: May 2006

This study examined students' perceptions of difficult or challenging clinical situations and how facilitators assisted students in relation to these specific situations Responses to open‐ended questions from first‐year nursing students before and after a series of hospital and community nursing practice placements were analysed The findings suggest that students do find certain clinical situations difficult or challenging and that facilitators can greatly assist students to effectively deal with these through specific teaching strategies
Education commissioning by consortia: some theoretical and practical issues relating to qualitative aspects of British nurse education
Authors: Humphreys John
Published: May 2006

In 1995 the British National Health Service (NHS) Executive published details of a new framework for planning and commissioning education and training in the NHS Among the central elements of these new arrangements are consortia of representatives from health care provider organizations and purchasing authorities among others, who will in due course take on responsibility for the commissioning of non‐medical education and training (NMET) This NMET market is clearly distinct from the larger ‘internal market’ for health care provision by virtue of its separate funding, and different supply and demand side components This paper includes an analysis of the new arrangements in terms of quasi‐market theory and articulates a key role for consortia in harmonising the distinct markets for health services and NMET A primary purpose of the paper is to examine the extent to which the new arrangements generally, and consortia in particular, can ensure that NMET contributes to NHS reform Evidence from consortium development work in the South Thames Regional Health Authority, England, is discussed and it is argued that consortia will only perform effectively if they receive devolved real powers to an extent that persuades members to genuinely commit themselves to the proper development of consortia and the responsibilities of NMET commissioning Finally a tendency to become preoccupied with education and training operations and processes rather than outputs is described and identified as a threat both to consortium effectiveness and educational innovation
A phenomenological study of the nature of empathy
Authors: Baillie Lesley
Published: May 2006

The purpose of this study was to gain an understanding of the nature of empathy, as perceived and experienced by registered nurses A phenomenological approach was selected, with nine experienced staff nurses working in surgical settings being interviewed using an open, unstructured approach Empathy was evidently felt to be beneficial, displayed both non‐verbally and through the nurse's actions, and therefore the ability to empathize, and to feel empathy with the individual patient, needs supporting and promoting in nurses The importance of learning from experience (both personal and professional), and the ability to communicate effectively, are both highlighted by this study The nature of empathy is evidently multi‐faceted, and the presence of empathy is influenced by a complex relationship between the individual nurse, patient and the environment It should be recognized that environmental issues, such as high workload and stress, also affect ability to empathize
Going to extremes: action research, grounded practice and the theory‐practice gap in nursing
Authors: Rolfe Gary
Published: May 2006

Action research is growing in popularity with nurse researchers, where it is often seen as a way of bridging the theory‐practice gap However, there is little agreement on exactly what is meant by the term, and most nurse researchers stop short of exploring the full potential of this methodology This paper argues that, if taken to its logical conclusion, action research methodology goes beyond the confines of the scientific paradigm and is able to bring about improvements in practice directly without the mediation of theory This has some important implications for how the research process is viewed, and results m a model of research which is participative, reflexive and unashamedly subjective, and which generates non‐generalizable, personal knowledge directly out of practice
Determining biogeographical patterns of dispersal and diversification in oscine passerine birds in Australia, Southeast Asia and Africa
Authors: Jønsson Knud A. , Fjeldså Jon
Published: May 2006

Aim  Several independent studies suggest that oscine passerine birds originated in Eastern Gondwana/Australia and from there spread to Southeast Asia and then to Africa. A recently constructed supertree including 1724 oscine taxa forms the basis for this study, in which we present a more detailed hypothesis of this out‐of‐Australia scenario.

Location  Australia, Africa, Southeast Asia, western Pacific, Indian Ocean.

Methods  We used the computer program DIVA to identify putative ancestral areas for each node. We also applied a molecular clock calibrated with three recently conducted studies of passerines to estimate the ages of basal nodes. Although these time estimates are rough they give some indication that, together with the putative ancestral areas, they can be compared with known events of plate tectonic movements in the Australian, Southeast Asian and western Pacific regions.

Results  The DIVA analysis shows that Basal Corvida and Crown Corvida originated in Australia. Ancestral nodes for Picathartes/Chaetops and Passerida originated in Africa, and the basal nodes of Sylvioidea also originated in Africa. For Muscicapoidea and Passeroidea we were unable to establish ancestral patterns. The molecular clock showed that Crown Corvida radiated between 20 and 30 Ma whereas Basal Corvida and the Passerida clade radiated from c. 45 to 50 Ma.

Main conclusions  Both approaches agree that: (1) Crown Corvida spread from Australia to Southeast Asia, with several dispersal events around the time when the terranes of Australian and Indomalayan origin came close together some 15 Ma, and (2) a single dispersal event went from Australia across the Indian Ocean to Africa c. 45–50 Ma, leading to the very large radiation of the parvorder Passerida. The latter hypothesis is novel, and contrary to the general view that oscines spread exclusively via Southeast Asia.
The effect of occlusal contact localization on the stress distribution in complete maxillary denture
Authors: ATEŞ M. , ÇILINGIR A. , SÜLÜN T. , SÜNBÜLOĞLU E. , BOZDAĞ E.
Published: May 2006

summary  The fracture of acrylic resin dentures is an unresolved problem in removable prosthodontics despite many efforts to determine its cause. Unfavourable occlusion could be playing an important role in the fracture of the denture. The aim of this study was to investigate the effect of occlusal contact localization on the stress distribution in complete maxillary denture bases utilizing two‐dimensional finite element analysis. The results of this study have shown that maximum compressive stresses in a complete maxillary denture under functional masticatory forces concentrates always on the artificial tooth/denture base junction irrespective to the occlusal contact localization. Tensile stresses were observed in areas toward the midline, although the midline itself usually had lower stresses. Shifting the occlusal contacts to a more buccal localization resulted in an increase of the calculated stresses. As a conclusion, it can be speculated that the buccal placement of the occlusal contacts may play a role in the fatigue fracture of the complete maxillary denture.
Odor identification accuracy declines following 24 h of sleep deprivation
Authors: KILLGORE WILLIAM D. S. , McBRIDE SHARON A.
Published: May 2006

Brain imaging studies demonstrate that sleep deprivation reduces glucose metabolism and blood flow in the prefrontal cortex, and such reductions are associated with impairments in cognitive functioning. Although some of the greatest metabolic declines occur within the orbitofrontal cortex, little is known about the effects of sleep loss on the types of processes mediated by this region, including emotion, motivation, feeding, and olfaction. The present study tested odor identification accuracy when individuals were well rested and again following 24 h of wakefulness. Relative to rested baseline performance, sleep‐deprived individuals demonstrated a significant decline in the ability to identify specific odors on the Smell Identification Test. This decrement in olfactory functioning occurred concomitantly with slowed psychomotor speed and increased ratings of self‐reported sleepiness. Performance on a task that required complex mental set shifting did not change significantly following sleep deprivation, suggesting that the decrements in odor identification could not be attributed to task difficulty. Finally, while there was no relationship between subjective sleepiness and odor identification at rested baseline, greater subjective sleepiness was associated with better odor identification ability following 24 h of sleep loss. Possible implications of these findings are discussed.
Evaluating the awakening criterion in the definition of nightmares: how certain are people in judging whether a nightmare woke them up?
Authors: BLAGROVE MARK , HAYWOOD SUZANNE
Published: May 2006

There is debate about whether to include in the definition of nightmares a criterion that the imagery or emotions of the nightmare caused the person to wake up. This study investigates whether people believe that they can judge this cause of awakening. 42 participants recorded for 14 nights whether they had a dream, and decided for each dream whether it had or had not woken them. They then rated on a 5‐point scale (where 1 = very certain and 5 = very uncertain) how certain they were in their decision of whether or not the dream woke them. Participants’ mean certainty was high for decisions that the dream woke them (mean certainty = 1.60), and for very unpleasant dreams this mean certainty that the dream woke them was very high (mean certainty = 1.27). Dreams judged to have caused awakening were found to be more unpleasant than dreams judged not to have caused awakening. Although the inclusion of the awakening criterion did not increase the association of nightmare frequency with anxiety, there may be other advantages in the use of the awakening criterion.
Who is pre‐occupied with sleep? A comparison of attention bias in people with psychophysiological insomnia, delayed sleep phase syndrome and good sleepers using the induced change blindness paradigm
Authors: MARCHETTI LAUREN M. , BIELLO STEPHANY M. , BROOMFIELD NIALL M. , MACMAHON KENNETH M. A. , ESPIE COLIN A.
Published: May 2006

Cognitive models of insomnia suggest that selective attention may be involved in maintaining the disorder. However, direct assessment of selective attention is limited. Using the inducing change blindness (ICB) paradigm we aimed to determine whether there is attentional preference for sleep‐related stimuli in psychophysiological insomnia (PI) relative to delayed sleep phase syndrome (DSPS) and good sleepers (GS). In the ICB task, a visual scene, comprising both sleep‐related and neutral stimuli, ‘flickers’ back and forth with one element (sleep or neutral) of the scene changing between presentations. Therefore, a 2 × 3 totally between‐participants design was employed. The dependent variable was the number of flickers it took for the participant to identify the change. Ninety individuals (30 per group) were classified using ICSD‐R criteria, self‐report diaries and wrist actigraphy. As predicted, PI detected a sleep‐related change significantly quicker than DSPS and GS, and significantly quicker than a sleep‐neutral change. Unexpectedly, DSPS detected a sleep‐related change significantly quicker than GS. No other differences were observed between the two controls. These results support the notion that there is an attention bias to sleep stimuli in PI, suggesting that selective attention tasks such as the ICB may be a useful objective index of cognitive arousal in insomnia. The results also suggest that there may be an element of sleep preoccupation associated with DSPS. Results are discussed with reference to other experiments on attentional processing in insomnia.
Challenging sleep in aging: the effects of 200 mg of caffeine during the evening in young and middle‐aged moderate caffeine consumers
Authors: DRAPEAU CAROLINE , HAMEL‐HÉBERT Isabelle , ROBILLARD RÉBECCA , SELMAOUI BRAHIM , FILIPINI DANIEL , CARRIER JULIE
Published: May 2006

The aim of this study was to evaluate the effects of a 200‐mg administration of caffeine on polysomnographic sleep variables and quantitative sleep electroencephalography (EEG) in 12 young (20–30 years) and 12 middle‐aged (40–60 years) moderate caffeine consumers (one to three cups of coffee per day). All subjects were submitted to both a caffeine (200 mg) and placebo (lactose) condition in a double‐blind cross‐over design. The conditions were separated by 1 week. Compared with the placebo condition, the evening ingestion of caffeine lengthened sleep latency, reduced sleep efficiency, and decreased sleep duration and amount of stage 2 sleep in both age groups. Caffeine also reduced spectral power in delta frequencies in frontal, central and parietal brain areas, but not in prefrontal (PF) and occipital regions. Moreover, caffeine increased spectral power in beta frequencies in frontal and central brain areas in both age groups. A suppression of spectral power in the PF area in low delta frequencies (0.5–1.00 Hz) and a rise in spectral power in the parietal region in high alpha (10.00–12.00 Hz) and beta frequencies (17.00–21.00, 23.00–25.00, 27.00–29.00 Hz) occurred solely in middle‐aged subjects. No such changes were noticeable in young subjects. Generally, caffeine produced similar effects in young and middle‐aged subjects. Only a few frequency bins showed more effects of caffeine in middle‐aged subjects compared with young subjects. Furthermore, sleep EEG results do not entirely support the hypothesis that caffeine fully mimics the effects of a reduction of homeostatic sleep propensity when following a normal sleep–wake cycle.
Sleep‐dependent changes in cerebral oxygen consumption in newborn lambs
Authors: SILVANI ALESSANDRO , ASTI VALENTINA , BERTEOTTI CHIARA , FERRARI VERA , FRANZINI CARLO , LENZI PIERLUIGI , WILD JENNENE , GRANT DANIEL ALLEN , WALKER ADRIAN MARK , ZOCCOLI GIOVANNA
Published: May 2006

During rapid‐eye‐movement (REM) sleep in adult subjects, the cerebral metabolic rate of oxygen consumption (CMRO2) is as high as that during wakefulness. We investigated whether CMRO2 during active sleep is already at the waking level in newborn life, to support the role of active sleep as a state of endogenous brain activation during early postnatal development. Newborn lambs, 2–5 days old (n = 6), were instrumented with electrodes for sleep‐state scoring, catheters for blood sample withdrawal and pressure monitoring, and a transit‐time ultrasonic blood‐flow probe around the superior sagittal sinus. At the age of 19 ± 3 days, blood samples were obtained simultaneously from the carotid artery and the superior sagittal sinus during uninterrupted epochs of wakefulness, quiet sleep, and active sleep. The arteriovenous difference in blood oxygen concentration was multiplied by cerebral blood flow to determine CMRO2. CMRO2 during active sleep (47 ± 5 μmol min−1) was similar to the value in wakefulness (44 ± 6 μmol min−1) and significantly higher than in quiet sleep (39 ± 5 μmol min−1, P < 0.05). These data show that active sleep provides newborn lambs with brain activity at a level similar to that in wakefulness in terms of cerebral oxygen metabolism. The high CMRO2 during active sleep supports its functional role during early postnatal development, when time spent in active sleep is at a lifetime maximum, albeit constituting a metabolic challenge for newborns, because of the impairment of systemic and cerebral vascular regulation in this sleep state.