bluuebunny/crossref_metadata_2025 huggingface dataset:
How Contingent Questioning Promotes Extended Student Talk: A Function of Display Questions
Authors: Boyd Maureen , Rubin Don
Published: October 2006

Research on traditional classrooms paints a picture of teachers controlling talk patterns and of students producing minimal amounts of mainly procedural talk, recitation-type talk, or both. Often this bleak state of affairs is attributed to teachers' overreliance on unauthentic display questions—questions that impose tight thematic control and therefore purportedly promote recitation rather than classroom dialogue. Contrary to this blanket indictment of display questions, however, a small number of previous studies have concluded that teacher display questions are not inherently inimical to engaged student talk. This study examined a small 4th-and 5th-grade English language learner classroom in which students were previously found to have produced a substantial number of socially engaged and structurally elaborated utterances. A new analysis of thematic episodes containing instances of extended student talk revealed that authenticity of teacher questions was not a necessary condition for triggering such student utterances. Indeed, text-based display questions that inquired about details of readings obviously known to the teacher elicited elaborated responses. The distinguishing characteristic of teacher questions that elicited extended student talk was found to be their contingency on previous student utterances rather than whether they were open-ended or inquired about known information.
her5expression reveals a pool of neural stem cells in the adult zebrafish midbrain
Authors: Chapouton Prisca , Adolf Birgit , Leucht Christoph , Tannhäuser Birgit , Ryu Soojin , Driever Wolfgang , Bally-Cuif Laure
Published: October 2006

Current models of vertebrate adult neural stem cells are largely restricted to the rodent forebrain. To extract the general mechanisms of neural stem cell biology, we sought to identify new adult stem cell populations, in other model systems and/or brain areas. The teleost zebrafish appears to be an ideal system, as cell proliferation in the adult zebrafish brain is found in many more niches than in the mammalian brain. As a starting point towards identifying stem cell populations in this system, we used an embryonic neural stem cell marker, the E(spl) bHLH transcription factor Her5. We demonstrate that her5 expression is not restricted to embryonic neural progenitors, but also defines in the adult zebrafish brain a new proliferation zone at the junction between the mid- and hindbrain. We show that adult her5-expressing cells proliferate slowly, self-renew and express neural stem cell markers. Finally, using in vivo lineage tracing in her5:gfp transgenic animals, we demonstrate that the her5-positive population is multipotent, giving rise in situ to differentiated neurons and glia that populate the basal midbrain. Our findings conclusively identify a new population of adult neural stem cells, as well as their fate and their endogenous environment, in the intact vertebrate brain. This cell population, located outside the forebrain, provides a powerful model to assess the general mechanisms of vertebrate neural stem cell biology. In addition, the first transcription factor characteristic of this cell population, Her5, points to the E(Spl) as a promising family of candidate adult neural stem cell regulators.
The allantois and chorion, when isolated before circulation or chorio-allantoic fusion, have hematopoietic potential
Authors: Zeigler Brandon M. , Sugiyama Daisuke , Chen Michael , Guo Yalin , Downs Karen M. , Speck Nancy A.
Published: October 2006

The chorio-allantoic placenta forms through the fusion of the allantois(progenitor tissue of the umbilical cord), with the chorionic plate. The murine placenta contains high levels of hematopoietic stem cells, and is therefore a stem cell niche. However, it is not known whether the placenta is a site of hematopoietic cell emergence, or whether hematopoietic cells originate from other sites in the conceptus and then colonize the placenta. Here, we show that the allantois and chorion, isolated prior to the establishment of circulation, have the potential to give rise to myeloid and definitive erythroid cells following explant culture. We further show that the hematopoietic potential of the allantois and chorion does not require their union, indicating that it is an intrinsic property of these tissues. These results suggest that the placenta is not only a niche for, but also a source of, hematopoietic cells.
Segment-specific requirements for dorsoventral patterning genes during early brain development inDrosophila
Authors: Urbach Rolf , Volland Dagmar , Seibert Janina , Technau Gerhard M.
Published: October 2006

An initial step in the development of the Drosophila central nervous system is the delamination of a stereotype population of neural stem cells (neuroblasts, NBs) from the neuroectoderm. Expression of the columnar genes ventral nervous system defective (vnd), intermediate neuroblasts defective (ind) and muscle segment homeobox (msh) subdivides the truncal neuroectoderm(primordium of the ventral nerve cord) into a ventral, intermediate and dorsal longitudinal domain, and has been shown to play a key role in the formation and/or specification of corresponding NBs. In the procephalic neuroectoderm(pNE, primordium of the brain), expression of columnar genes is highly complex and dynamic, and their functions during brain development are still unknown. We have investigated the role of these genes (with special emphasis on the Nkx2-type homeobox gene vnd) in early embryonic development of the brain. We show at the level of individually identified cells that vnd controls the formation of ventral brain NBs and is required, and to some extent sufficient, for the specification of ventral and intermediate pNE and deriving NBs. However, we uncovered significant differences in the expression of and regulatory interactions between vnd, ind and msh among brain segments, and in comparison to the ventral nerve cord. Whereas in the trunk Vnd negatively regulates ind, Vnd does not repress ind (but does repress msh) in the ventral pNE and NBs. Instead, in the deutocerebral region, Vnd is required for the expression of ind. We also show that, in the anterior brain (protocerebrum),normal production of early glial cells is independent from msh and vnd, in contrast to the posterior brain (deuto- and tritocerebrum)and to the ventral nerve cord.
DNA supercoiling factor contributes to dosage compensation inDrosophila
Authors: Furuhashi Hirofumi , Nakajima Mikage , Hirose Susumu
Published: October 2006

DNA supercoiling factor (SCF) is a protein capable of generating negative supercoils in DNA in conjunction with topoisomerase II. To clarify the biological functions of SCF, we introduced a heritable SCF RNAi into Drosophila. Upon knockdown of SCF, we observed male lethality and male-specific reduction in the expression levels of X-linked genes. SCF functionally interacts with components of the MSL complex, which are required for dosage compensation via hypertranscription of the male X chromosome. Moreover, SCF colocalizes with the MSL complex along the male X chromosome. Upon overexpression of SCF, the male X chromosome had a bloated appearance. This phenotype was dependent on the histone acetyltransferase MOF and was suppressed by simultaneous overexpression of ISWI. These findings demonstrate that SCF plays a role in transcriptional activation via alteration of chromatin structure and provide evidence that SCF contributes to dosage compensation.
Genetic analysis of EphA-dependent signaling mechanisms controlling topographic mapping in vivo
Authors: Dufour Audrey , Egea Joaquim , Kullander Klas , Klein Rüdiger , Vanderhaeghen Pierre
Published: October 2006

Ephrin/Eph ligands and receptors are best known for their prominent role in topographic mapping of neural connectivity. Despite the large amount of work centered on ephrin/Eph-dependent signaling pathways in various cellular contexts, the molecular mechanisms of action of Eph receptors in neural mapping, requiring dynamic interactions between complementary gradients of ephrins and Eph receptors, remain largely unknown. Here, we investigated in vivo the signaling mechanisms of neural mapping mediated by the EphA4 receptor, previously shown to control topographic specificity of thalamocortical axons in the mouse somatosensory system. Using axon tracing analyses of knock-in mouse lines displaying selective mutations for the Epha4 gene, we determined for the first time which intracellular domains of an Eph receptor are required for topographic mapping. We provide direct in vivo evidence that the tyrosine kinase domain of EphA4, as well as a tight regulation of its activity, are required for topographic mapping of thalamocortical axons, whereas non-catalytic functional modules, such as the PDZ-binding motif (PBM) and the Sterile-α motif (SAM) domain, are dispensable. These data provide a novel insight into the molecular mechanisms of topographic mapping, and constitute a physiological framework for the dissection of the downstream signaling cascades involved.
Jagged 1 is a β-catenin target gene required for ectopic hair follicle formation in adult epidermis
Authors: Estrach Soline , Ambler Carrie A. , Lo Celso Cristina Lo , Hozumi Katsuto , Watt Fiona M.
Published: October 2006

The Wnt and Notch signalling pathways regulate hair follicle maintenance,but how they intersect is unknown. We show that Notch signalling is active in the hair follicle pre-cortex, a region of high Wnt activity, where commitment to hair lineages occurs. Deletion of jagged 1 (Jag1) results in inhibition of the hair growth cycle and conversion of hair follicles into cysts of cells undergoing interfollicular epidermal differentiation. Conversely, activation of Notch in adult epidermis triggers expansion of the base of the hair follicle, sebaceous gland enlargement and abnormal clumping of the follicles. In adult epidermis, the induction of new hair follicle formation by β-catenin is prevented by blocking Notch signalling pharmacologically or through Jag1 deletion. Conversely, activation of both pathways accelerates growth and differentiation of ectopic follicles.β-catenin stimulates Notch signalling by inducing Jag1transcription. We conclude that the Notch pathway acts downstream of the Wnt/β-catenin pathway to determine epidermal cell fate.
Microtubule nucleation: γ-tubulin and beyond
Authors: Wiese Christiane , Zheng Yixian
Published: October 2006

Centrosomes and their fungal equivalents, spindle pole bodies (SPBs), are the main microtubule (MT)-organizing centers in eukaryotic cells. Several proteins have been implicated in microtubule formation by centrosomes and SPBs, including microtubule-minus-end-binding proteins and proteins that bind along the length or stabilize the plus ends of microtubules. Recent work has improved our understanding of the molecular mechanisms of MT formation. In particular, it has shown that γ-tubulin and its associated proteins play key roles in microtubule nucleation and spindle assembly in evolutionarily distant species ranging from fungi to mammals. Other work indicates that γ-tubulin-mediated microtubule nucleation, although necessary, is not sufficient for mitotic spindle assembly but requires additional proteins that regulate microtubule nucleation independently of centrosomes.
Residual stress measurement using indentation and a radial electronic speckle pattern interferometer — recent progress
Authors: Suterio R , Albertazzi A , Amaral F. K
Published: October 2006

A new kind of electronic speckle pattern interferometer (ESPI) was developed by the authors' group using conical mirrors to measure the radial in-plane displacement component. True radial in-plane sensitivity is achieved by double illumination. This device is used in the present work to measure residual stresses in combination with the indentation method. A semi-empirical mathematical model is developed to quantify the residual stresses. Several tests were made on a specimen with different levels of stress imposed by mechanical loading. Empirical constants were computed from these tests and are used in combination with the developed model to predict the residual stress levels. The tests presented here are preliminary as they are restricted to only one material, a uniaxial stress state, one geometry of the indentation tip, and only one value of indentation force. In these conditions the results are very encouraging, a typical measurement error of about 5 per cent being found for the principal residual stress.
Thermoelastic studies on Nitinol stents
Authors: Eaton-Evans J , Dulieu-Barton J. M , Little E. G , Brown I. A
Published: October 2006

In this paper a methodology for applying thermoelastic stress analysis (TSA) to superelastic, nickel-titanium (Nitinol), shape memory alloy self-expanding stents is described. A test rig has been designed that allows the stents to be loaded under a pseudophysiological loading of internal pressure. High-resolution thermoelastic data obtained from a stent are presented, and features in the data are identified where high signal and potentially high stresses exist. The data are examined in detail and it is demonstrated that the thermoelastic signal is linearly related to internal pressure but is also dependent on mean stress. To gain further understanding of the thermoelastic response of Nitinol, a series of calibration-type experiments were conducted on thin-walled Nitinol cylinders so that the thermoelastic response of Nitinol was characterized throughout its non-linear elastic range. The effect of the mean stress on the signal was identified experimentally and compared with theoretical calculations. It is suggested that, if testing is conducted at elevated temperature (>37°C), these effects can be eliminated and quantitative analysis can be achieved. Other issues such as non-adiabatic behaviour and strain rate dependence are also discussed.
Environment effect on low cycle fatigue properties of some titanium alloys
Authors: Medekshas H
Published: October 2006

In this paper an attempt is made to investigate the effect of the environment on the low-cycle fatigue properties of four titanium alloys. The influence of an elevated temperature (200-650°C) and increased amount of hydrogen (0.004-0.08 wt%) in the alloy on the cyclic strength at constant-stress and constant-strain loading is analysed. Round ( d = 10 mm) and rectangular cross-section (4 mm x 25 mm) smooth and notched specimens were tested. Fatigue crack initiation (length a ≈ 0.5 mm) and growth were observed by optical microscopy. The numbers of cycles to crack initiation and to final fracture were fixed. Analysis of the test data enabled the effects of both the temperature and hydrogen on the specimen lifetime to be determined.
Characteristic study of bushing compliance in consideration of stresses in a vehicle suspension system by the Taguchi method
Authors: Kim Jeong Ho , Sin Hyo-Chol , Kang Bong Jin , Kim Nam Woong
Published: October 2006

The dynamic loads imposed on suspension components during vehicle driving are transferred through bushings and joints. The loads from bushings are important factors in the prediction of the fatigue life of a component and the dynamic characteristics of a vehicle. In this paper, the linear characteristic of a bushing is approximated by finite element analysis and applied to a multi-body dynamic model of the vehicle. The influence of bushing compliance is investigated, considering the dynamically responsive stress of the lower control arm in a virtual proving ground test. With the bushing compliance of the front suspension as a design parameter, the Taguchi method is used in the systematic process of a robust design to reduce the stress value of the lower control arm.
Modelling and control of a non-linear dynamic system for heavy-duty trucks
Authors: Yang Bin , Keqiang Li , Ukawa Hiroshi , Handa Masatoshi
Published: October 2006

In this paper, modelling and control of the non-linear longitudinal dynamic system for heavy-duty trucks are implemented. Based on the non-linear model, feedback linearization is employed to convert the non-linear system to a linear canonical form. Owing to the influence of the control variable time delay in the non-linear brake subsystem, an extended feedback linearization based on the non-linear Smith predictive method is proposed, which not only compensates for the control variable time delay effectively but also makes the non-linear system behave like a linear system. Finally, a tracking control algorithm is investigated for the linear canonical form to obtain more precise acceleration/deceleration tracking under low-speed conditions.
Coordination of active steering, driveline, and braking for integrated vehicle dynamics control
Authors: He Junjie , Crolla D A , Levesley M C , Manning W J
Published: October 2006

An integrated vehicle dynamics control system which aims to improve vehicle handling and stability by coordinating active front steering (AFS) and dynamic stability control (DSC) subsystems is developed in this paper. The DSC subsystem includes driveline-based, brake-based, and driveline plus brake-based DSC subsystems. The influence of varying forward speed and lateral acceleration on the lateral vehicle dynamics is investigated first. The AFS controller, which is used to improve vehicle steerability in the low to mid-range lateral acceleration, and the DSC controller, which manages to maintain vehicle stability during extreme driving situations, are then designed by using the sliding mode control (SMC) technique and phase plane method respectively. Based on the two independently developed controllers, a rule-based integration scheme is proposed to optimize the overall vehicle performance by minimizing interactions between the two subsystems and extending functionalities of individual subsystems. Computer simulation results confirm the effectiveness of the proposed control system and the overall improvements in vehicle handling and stability.
Use of distributed-memory parallel processing in computing the dynamic response of the passenger—car system
Authors: Kim Chang-wan
Published: October 2006

Dynamic response analysis of an automobile is performed in parallel with distributed-memory parallel processors. Firstly, the parallel Lanczos algorithm is implemented in order to obtain partial eigensolutions. Then, parallel modal frequency response analysis is performed. This approach is effective for seamless interfacing of the parallel Lanczos method and modal frequency response analysis with industry car finite element (FE) models requiring dynamic response analysis. The performance of parallel processing is measured for large-scale industry finite element models.
Design for environment analyses applied to rapid manufacturing
Authors: Hopkinson N , Gao Y , McAfee D J
Published: October 2006

This paper explores the potential to combine rapid manufacturing (RM) technologies and design for environment (DFE) software with an automotive application. The work focuses on the redesign of a door handle assembly for the Jaguar XJ Saloon. The original 11-piece assembly, comprising eight different materials, was subject to a redesign with an RM technology in mind as the method for final manufacture. In this case the suggested method for manufacture was selective laser sintering (SLS). The design freedoms afforded by the SLS process had a profound effect on the potential to redesign the product. Two different redesigns were proposed, and these, along with the original design, were subjected to analyses of environmental burden and financial profits/costs for end-of-life recycling and reuse using Boothroyd Dewhurst DFE software. The first redesign incorporated the entire assembly as a single prefabricated unit and consequently rendered a DFE analysis impossible. The second redesign was a four-piece assembly retaining three metallic components from the original product and, when subjected to the DFE analysis, showed a significant reduction in environmental burden and cost for disassembly. The surface finish of the SLS parts proved to be inadequate for visual components on a luxury car, but the potential to apply RM for applications with less stringent aesthetic requirements remains.
Effect of obstacles on the indicators of road unevenness
Authors: Kropáč O , Múčka P
Published: October 2006

A simulation study of the effect of a large obstacle (a bump or a depression) on standard parameters of the road unevenness power spectral density (PSD) is presented. Two basic types of obstacles are considered. The so-called technological obstacle is modelled by a trapezoid of length 1 m and variable height. The random obstacle is modelled using cosine waves of variable height and constant height/length ratio. In both cases, the density of obstacles on a 1024-m-long road section is also considered. It appears that even a small obstacle on a high-quality surface causes significant deformation of the PSD, the effect being greater on the unevenness index. Profiles with a large number of randomly distributed cosine obstacles with random heights result in the PSD with two straight lines intersecting at the circular spatial frequency of 4-6 rad/m. It appears that this could be a good model for a deteriorated road. Thus, the aim of the work presented in this paper is to show the value of the simulation approach used and the practical value of particular results obtained, especially as an initial impulse to further extensive research activities in this field.
Buckling of laser-welded sandwich panels. Part 1: Elastic buckling parallel to the webs
Authors: Kolsters H , Zenkert D
Published: October 2006

This is the first of three companion papers that examine the elastic buckling and collapse of laser-welded sandwich panels with an adhesively bonded core and uni-directional vertical webs. In compression parallel to the webs, the face sheet in between two webs can be treated as a long rectangular plate supported at the sides and resting on a continuous elastic foundation. Using a generalized form of the Kirchoff equation, the plate buckling load is evaluated for a Winkler and Pasternak foundation, and for a foundation model where the core is characterized by an elastic half-space. Although the elastic half-space model is most sophisticated in the way that the decay of transverse stress through the core is described, it requires that the buckling load is calculated iteratively and is therefore not suitable for engineering applications. In contrast, the Pasternak foundation model is able to demonstrate the effect of different boundary conditions at the laser weld and different core properties by the variation of a simple clamping factor and two foundation moduli. By changing the clamping factor, the model can be used to describe plate buckling as well as wrinkling, and, by varying the foundation moduli, it is possible to distinguish between symmetrical and anti-symmetrical buckling modes. Evaluation of the buckling solution shows that, for low modulus core materials, the plate buckling strength is determined only by the boundary conditions at the laser weld, while for high modulus materials anti-symmetrical wrinkling dominates. To improve the accuracy of the solution for non-standard configurations, the foundation moduli are calibrated using the elastic half-space model and finite element results as a reference. It is found that, by using a smaller Winkler foundation modulus, the accuracy and consistency of the Pasternak model are improved considerably. However, the results also show that, for current sandwich configurations, the proportional limit of the face plate material is usually reached well before elastic buckling occurs. All experimental work is therefore delegated to the third paper, which deals with extension of the Pasternak foundation model into the elasto-plastic regime and non-linear finite element modelling.
Wave period group statistics for real sea waves and wave energy extraction
Authors: Smith G H , Venugopal V , Wolfram J
Published: October 2006

The paper describes the analyses of wave data recorded at various locations and water depths around northern Europe to determine the temporal characteristics of individual wave periods and other wave period statistics. These analyses show that, just as there are group characteristics for wave heights, there are similar, but less pronounced, characteristics for wave periods. This is observed in three separate sets of data from different locations in water depths of 18, 50, and 130 m. It is also found in time series simulated using random linear wave theory from a Jonswap spectrum. A simple, new statistic, R, is introduced that measures the rate of change in the wave period from one wave to the next. This is relevant to wave energy devices that may try to tune themselves to obtain optimum power output from each individual wave. The characteristics of this statistic and its variation with significant wave height, mean energy period, and spectral bandwidth have been examined for the three datasets and are discussed. It is found that the R statistic can be fitted quite well by a Gaussian distribution for all the datasets examined. In a real sea there will be many small waves with comparatively very little energy, and the effect of filtering these out upon the R statistic has been examined. It is seen that removing the small waves has very little effect upon the energy available for extraction but significantly reduces the rate at which the wave energy device must retune to obtain optimum power conversion. This is illustrated by considering a hypothetical wave energy device, with a representative power transfer function, that can retune at prescribed rates. It is shown that being able to tune to individual waves can greatly increase power output.
On the difficulty of inventing an economical sea wave energy converter: A personal view
Authors: French M J
Published: October 2006

Sea waves are a promising potential source of renewable energy, but the technology has not yet settled down to one or two basic forms as has happened with most major inventions. New ideas continue to arise, and no general agreement about how to proceed seems to be emerging. Moreover, although practicable wave energy converters (WECs) have been developed, they are not as economical as might have been hoped.

This paper explores a particular aspect of the cost problem. Broadly speaking, the costs of WECs are high because they deal with large forces moving slowly. It is reasonable to expect that where a working surface can be identified, the bigger its area is relative to the overall surface area and the faster the surface moves, the more economical it is likely to be. This suggests two criteria for an economical WEC: a large working area relative to its size and a high ratio of the speed of that surface to the particle speed of the wave. The second criterion indicates a resonant system, and this paper is confined to WECs that have quasi-resonant working surfaces (QR WECs). The quasi- is because the mechanics involved is not quite that of classical resonance.

Promising types are listed in four groups according to the source of reaction, because this is generally the most difficult function to provide in QR WECs. Other types of WEC are left out, most often because they do not meet the criteria of a strongly coupled working surface and resonance, and usually require large amounts of material. While size is not uniquely related to cost, WECs using much material are likely to be expensive.
Parallel multi-model switched control for ship roll stabilization
Authors: Roberts G N , Cournou V , Vinsonneau B , Burnham K J
Published: October 2006

This paper concerns the application of a parallel multi-model switched control (PMMSC) scheme for integrated fin and rudder roll stabilization (INFRRS). The PMMSC algorithm uses a two-level hierarchical control strategy where, at the lower level, a bank of controller pairs (fin roll and rudder roll controllers) are designed for a range of preselected operating conditions, and, at the upper level, a decision maker decides which controller pair is most suited to the prevailing conditions and ensures that the appropriate controller pair is switched into operation. A novel approach of characterizing roll angle data using power spectral density (PSD) histograms is presented. It is shown how the PSD histograms for different encounter angles exhibit sufficiently different characteristics to enable them to be used by the PMMSC algorithm to produce reliable switching between controller pairs. Simulation studies demonstrate the efficacy of the PMMSC when applied to an identified ship model.
Network Supported Media Delivery in Ambient Networks (Netzwerkunterstützte Medienverteilung)
Authors: Schieder Andreas , Kampmann Markus , Hartung Frank , Vorwerk Marc , Rembarz René
Published: October 2006

This paper presents the vision of Ambient Networking, which is proposed to constitute the control layer of future B3G networks. The main characteristics of the Ambient Network Control Space are introduced and the Ambient Network Media Delivery function is explained in more detail to provide an example for a typical control space component. The description of a Media Delivery prototype complements this article.
Clinical and Genetic Features of Van der Woude Syndrome in Two Large Families in Brazil
Authors: Martelli-Junior Hercílio , Chaves Marcelo Reis , Swerts Mário Sérgio Oliveira , de Miranda Roseli Teixeira , Bonan Paulo Rogério Ferreti , Coletta Ricardo D.
Published: October 2006

Objective:

This report describes the clinical and genetic features of two large and unrelated families with Van der Woude syndrome in Brazil, emphasizing the range of anomalies found within and between the families.

Patients:

Family 1 included 54 descendants spanning five generations, with 12 (22.23%) individuals manifesting Van der Woude syndrome. In family 2, examinations comprised 17 descendants distributed over four generations, and 8 (47.06%) people presented features of Van der Woude syndrome.

Results:

In family 1, the first two generations were not affected, but the other three generations had affected members showing a unique association of lip pits and cleft lip/palate with equilibrated gender distribution. In family 2, all generations were affected, and the clinical expression of disease was heterogeneous, including members with isolated clefts, isolated lip pits, and association of cleft lip/palate with lip pits. In both families, affected members transmitted their traits to descendants in an autosomal dominant mode of inheritance with apparent low penetrance in family 1, but high penetrance in family 2. Patients were treated surgically by cheiloplasty and/or palatoplasty with satisfactory results.

Conclusions:

Van der Woude syndrome was transmitted by an autosomal dominant pattern with variable expressivity and penetrance and equilibrated gender distribution. Physicians should be aware of the variety of malformations that can be associated with Van der Woude syndrome. Genetic counseling in Van der Woude syndrome affected families is important, because a high percentage of descendants can have some kind of clefting.
The Impact of Early Retirement on Perceptions of Life at Work and at Home: Qualitative Analyses of British Civil Servants Participating in the Whitehall II Retirement Study
Authors: Mein Gill , Ellison George T. H.
Published: October 2006

This study examined pathways to retirement and the role of circumstances at work and at home (including the introduction of financially-enhanced early retirement schemes) on retirement-related decision-making. In-depth qualitative interviews were conducted within 2 years of retirement with 59 British civil servants participating in the Whitehall II Study. Focusing on the experiences of 33 interviewees who spontaneously discussed “early retirement” we identified three pathways to retirement (non-applicants, successful applicants, and unsuccessful applicants for early retirement) each influenced by a range of complementary positive and negative factors at work and at home. The early retirement schemes influenced the balance between these factors in three ways: by encouraging participants to reflect on (and reconsider) existing retirement plans; by offering financial incentives to retire early; and because they were part of the ongoing process of restructuring and downsizing within the Civil Service which was accompanied by a perceived deterioration in conditions at work.
Changes in US Primary Care Access and Capabilities During the COVID-19 Pandemic
Authors: Mackwood Matthew , Fisher Elliott , Schmidt Rachel O. , Yang Ching-Wen W. , O’Malley A. James , Rodriguez Hector P. , Shortell Stephen , Akré Ellesse-Roselee L. , Schifferdecker Karen E.
Published: February 2025

Importance

Many of the capabilities needed to deliver accessible, high-quality primary care have been defined, but little is known about how their implementation has changed in US practices over the course of the COVID-19 pandemic or about the factors associated with greater capabilities.

Objective

To describe US primary care practices’ accessibility and capabilities and examine recent changes.

Design, Setting, and Participants

This was a retrospective cohort study across 2 surveys, in 2017 to 2018 and 2022 to 2023, among a national sample of primary care practice leaders in the US. Data were analyzed from January 2023 to September 2024.

Exposures

Degree of integrated practice ownership and accountable care organization (ACO) participation.

Main Outcomes and Measures

Differences by practice ownership and ACO participation, and changes over time in access to care and care delivery capabilities. These were measured by composite scores of responses standardized to a scale of 0 to 100.

Results

This analysis included 710 practices, of which 234 were independently owned, 105 were physician group owned, and 321 were hospital/health system owned in 2017 to 2018, and 68 practices reported no ACO participation, 107 joined between surveys, and 486 otherwise participated in ACOs. Access to care (measured as extended weekday or weekend hours) was reported to decline from the first survey in 2017 to 2018 to the second in 2022 to 2023. Hospital/health system practices and ACO participants had higher rates of extended weekday hours than their comparators in 2022 to 2023. Average capability scores increased from 51 to 54 (increase of 4 points [95% CI, 1-6 points]). There was wide variation in scores within all ownership and ACO participant or nonparticipant groups. Capability scores were higher on average for more integrated practices (for physician groups compared to independent practices, 12 points [95% CI, 5-19 points] in 2017-2018 and 12 points [95% CI, 7-16 points] in 2022-2023) and for ACO participants compared to nonparticipants (13-point difference [6 to 20] in 2017-2018 and 12-point difference [6 to 18] in 2022-2023).

Conclusions and Relevance

In this cohort study, over the time period including the COVID-19 pandemic, primary care practices reported a decline in access to care, while average practice capabilities improved. Integrated practice ownership and ACO participation were both associated with better access and capability scores, suggesting that value-based payment and integrated care delivery support the development of higher-quality primary care. Variations across practices point to large opportunities for improvement overall and underscore the importance of incentives and structures as levers to improve primary care delivery.
Trends in Psychiatrist-Led Care for Medicare Part B Enrollees
Authors: Havlik John L. , Wahid Syed , Priest Kelsey C. , Ososanya Lydia , Igunbor Marissa , Humphreys Keith
Published: February 2025

Importance

The rising incidence of mental illness in the US underscores the need for timely access to psychiatric care, especially for vulnerable populations such as older adults and individuals with mental and physical disabilities who receive Medicare.

Objective

To assess changes in the number and proportion of active psychiatrists providing professional services to traditional Medicare Part B enrollees from 2014 to 2022.

Design, Setting, and Participants

This repeated cross-sectional study of Medicare Part B enrollees used publicly available data (for January 1, 2014, through December 31, 2022) from the Centers for Medicare & Medicaid Services and the Kaiser Family Foundation. Data from all traditional Medicare Part B enrollees in all 50 states and the District of Columbia were analyzed.

Main Outcomes and Measures

Primary outcomes included changes in (1) the proportion of active psychiatrists billing traditional Medicare and (2) the number of psychiatrists providing care relative to the number of Medicare Part B enrollees nationally, regionally, and by state.

Results

The study population comprised 291 748 472 Medicare Part B enrollee-years (33 042 936 in 2014: 5 800 903 [17.6%] eligible due to disability alone and 27 242 030 [82.4%] eligible due to age). From 2014 to 2022, the number of Medicare Part B enrollees decreased by 3 497 942 enrollee-years (10.6%), while the number of psychiatrists submitting more than 10 claims to Medicare Part B decreased by 3772 (16.8%). The nationwide proportion of professionally active psychiatrists submitting claims to Medicare Part B for professional services during this period declined from 22 409 of 50 416 (44.4%) in 2014 to 18 637 of 56 492 (33.0%) in 2022 (P < .001 on univariable regression). From 2014 to 2022, state-level changes in Medicare Part B–serving psychiatrists per enrollee ranged from a 31.7% increase in Alabama (from 36.5 to 48.1 psychiatrists per 100 000 enrollees) to a 67.8% decrease in Wyoming (from 42.9 to 13.8 psychiatrists per 100 000 enrollees). Every state and district assessed saw a decrease in the percentage of active psychiatrists who billed Medicare Part B for professional services over the study period.

Conclusions and Relevance

In this study of Medicare Part B acceptance among active US psychiatrists, declining acceptance of Medicare Part B for professional services among psychiatrists was observed nationally and across all states. During a time of psychiatrist workforce growth, the number of psychiatrists accepting traditional Medicare decreased, indicating potential challenges in providing equitable access to psychiatric care.
Pixel Intensity to Estimate Choroidal Tumor Thickness Using 2-Dimensional Ultra-Widefield Images
Authors: Yu Michael D. , Heiferman Michael , Korot Edward , Ahluwalia Aneesha , Yu Gina , Mruthyunjaya Prithvi
Published: February 2025

Importance

Tumor thickness is a well-established risk factor for malignant transformation of choroidal nevus into melanoma. To date, reliable evaluation of tumor thickness relies on B-scan ultrasonography, which is frequently unavailable at nonsubspecialty clinics where most melanocytic choroidal lesions (MCLs) are first diagnosed.

Objective

To describe a technique for potential rapid and reliable estimation of MCL thickness using only Optomap ultra-widefield (UWF) images without B-scan ultrasonography.

Design, Setting, and Participants

This retrospective, exploratory, cross-sectional analysis of consecutive MCLs diagnosed at Byers Eye Institute, Stanford University, Palo Alto, California, investigates the quantitative correlation between B-scan ultrasonographic thickness of MCLs with the relative pixel intensity of MCLs on green-channel (GC) Optomap UWF images. Pixel intensity overlying the lesion was standardized to the pixel intensity surrounding the lesion (pixel intensity difference [PID]), which was then correlated with ultrasonographic tumor thickness in all study lesions using linear regression analysis. Data were collected from January 1, 2019, to July 1, 2021.

Main Outcomes and Measures

The correlation between ultrasonographic tumor thickness and PID was measured. Performance (sensitivity and specificity) of the regression analysis trendline in estimating tumor thickness was also determined.

Results

A total of 138 MCLs from 138 patients (mean age, 57.0 years; 51% female) were included, comprising 125 that were nevi and 13 that were melanoma. The mean ultrasonographic tumor thickness was 1.1 mm (median, 0.8 mm; range, 0.2-5.5 mm), with a mean PID of 2.13. Stratifying lesions by ultrasonographic thickness (<1.0 mm vs 1.0-2.0 mm vs >2.0 mm), the mean PID increased (−1.95 vs 3.72 vs 17.62; P < .001) as mean thickness increased (0.5 mm vs 1.4 mm vs 3.3 mm; P < .001). PID was correlated with tumor thickness (R2 = 0.823; 95% CI, 0.770-0.875; P < .001) across lesions of all sizes.

Conclusions and Relevance

In this proof-of-principle study, GC-derived lesion intensity correlated well with ultrasonographic tumor thickness. Leveraging this correlation, this study demonstrates a technique for potentially reliable and rapid estimation of tumor thickness using UWF Optomap images without the use of B-scan ultrasonography.
Archetypes of nature‐based solutions for farming in the North York Moors National Park
Authors: Barrios Luisana , Arnott David , Thompson Rebecca , Marchant Rob
Published: February 2025

Nature‐based solutions (NbS) have emerged as crucial strategies to address climate change challenges, offering manifold benefits to biodiversity and communities by safeguarding, linking, and rejuvenating ecosystems.

We identify and analyse how NbS have been applied within the farming in protected landscapes programme in the North York Moors National Park, England, focusing on the assessment of interventions, archetypes, approaches, challenges, and the delivery of ecosystem services.

Using archetype analysis, this study provides a uniform framework of NbS types in 31 projects carried out throughout the National Park. The results show schemes that encompass climate adaptation, community‐based adaptation, ecosystem‐based management, ecological restoration, natural resource management, and sustainable agriculture schemes. Five key approaches were identified, including connection to nature, ecological restoration, enhancement of water quality, fencing, and tree planting.

Practical implication. From a perspective of NbS diversity and its implementation across the wider landscape, this research offers valuable insights for policymakers, practitioners, and researchers aiming to enhance the efficacy of NbS in protected landscapes around the world.
Initial Practice Performance Moderates the Distributed Practice Effect in Complex Procedural Knowledge
Authors: Ruitenburg Sterre K. , Guldemont Pieter , Kirschner Paul A. , Jarodzka Halszka , Camp Gino
Published: February 2025

Successful adoption of proven effective practice strategies such as distributed practice may contribute to much‐needed improvement in mathematics performance. However, it is not yet fully understood if distributed practice is beneficial for long‐term retention of complex procedural knowledge and, if so, for which initial practice performance level this spacing effect occurs. To investigate these two questions, we used a randomised between‐subjects design (Practice Strategy: massed vs. distributed) with 61 primary school students' mathematical problem‐solving performance as dependent variable. First, as hypothesised, we found a spacing effect on students' problem‐solving performance. Second, again as hypothesised, we found that the magnitude of this spacing effect depended on their initial practice performance. Our findings imply that distributed practice leads to better long‐term problem‐solving performance than massed practice, but only for students with medium initial practice performance who have not yet completely mastered the task.
Improved Antibacterial Properties of Additively Manufactured Ti–6Al–4V Surface Machined by Wire Electro‐Discharge Machining
Authors: Omarov Salikh , Nauryz Nurlan , Ali Shahid , Kenessova Ainur , Pham Tri , Talamona Didier , Perveen Asma
Published: February 2025

Titanium alloys are the most demanded material type in implant applications. However, developing bacteria‐resistant implant characteristics is still in the progress of the research field. In this study, the performance of micro‐wire electro‐discharge machining (μ‐WEDM) surface modification technique on Ti–6Al–4V alloy is investigated. The performance parameters such as material removal rate, kerf width, surface roughness, and crater size are evaluated in terms of capacitance and gap‐voltage input parameters. In addition, the adhesion of bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Bacillus subtilis on treated surfaces is tested. Results show that the difference in discharge energy affects surface biofilm prevention performance. According to that, Pseudomonas aeruginosa, Escherichia coli, and Bacillus subtilis attach more on surfaces with 0.727 μm roughness which are machined with 10 nF and 100 V. Staphylococcus aureus attaches more on surfaces with 0.211 μm roughness machined with 1 nF and 90 V. Meanwhile, surface with 1.531 μm roughness, machined with 100 nF and 110 V, provides the least number of bacteria attached to the surface for all strains except Bacillus subtilis. In conclusion, this study found that μ‐WEDM surface treatment techniques can increase biofilm prevention properties of implant surfaces for different bacteria strains, within a certain range of discharge energy.
Effects of Creep in Titanium at Room Temperature during Tensile and Profilometry‐Based Indentation Plastometry Testing
Authors: McKeown Philip John , Miller James Rees , Clyne Trevor William
Published: February 2025

This work concerns the mechanical response of three Ti‐based alloys at room temperature, which is observed to be “creep‐affected” and hence to exhibit a dependence on time (within the “quasi‐static” range of strain rate). They have been tensile tested (over this range of strain rate) and subjected to profilometry‐based indentation plastometry (PIP) with a range of penetration velocities (and hence of effective average strain rate). In addition, they have been creep tested, with different fixed loads (corresponding to nominal stresses in the vicinity of the yield stress). Using the Miller–Norton equation to capture creep strain histories, the outcomes of these tests have been converted so that they correspond to those expected with a fixed true stress. These characteristics have then been used in a simple numerical model of a tensile test, incorporating the effect of creep. Good overall consistency is observed and the procedures described here are thought to have wide potential for the extraction of both plasticity and creep characteristics from a simple series of tensile (or PIP) tests carried out with a range of strain rates.
Sulfur‐Bridged Pure Organic Ester Clusters Exhibiting Near‐Infrared Fluorescence
Authors: Liu Xiong , Guo Jiafang , Xiong Zuping , Li Xiang , Lv Yanbing , Zhang Ziteng , Chu Bo , Zhang Haoke , Sun Jing Zhi , Zhang Xinghong , Tang Ben Zhong
Published: February 2025

The development of near‐infrared (NIR) luminophores offers significant potential in the life sciences, yet constructing pure organic clusteroluminescence (CL) from nonconjugated polymers via through‐space interaction (TSI) remains a substantial challenge. Herein, it is revealed that sulfur (S) functions as a bridge between isolated ester groups in small molecule models, facilitating (n, π*) transitions. Building on this, RCP1‐RCP5 and P1‐P4 are synthesized to produce pure organic NIR‐CL luminophores. The introduction of S enhances chain clustering in polyesters and modulates inter‐/intra‐chain TSI, while micro‐folding within chains promotes clustering of adjacent ester groups and S atoms, resulting in a marked redshift. Notably, P4 displayed a fluorescence peak at 800 nm, extending to 883 nm, which sets a new record for CL. Additionally, full‐color fluorescent fibers are fabricated and explored the application of clusteroluminescent dyes. This work deepens the understanding of CL mechanisms and provides critical insights for developing high‐efficiency organic clusteroluminescent materials.