769 research outputs found
A novel bee host cannot detect a microbial parasite, in contrast to its original host
Organisms that can detect parasites may have a greater likelihood of avoiding exposure to them. We would expect hosts that share an evolutionary history with a parasite to be more likely to detect and avoid it compared to novel hosts. Nosema ceranae is a gut parasite of the Asian honey bee, Apis cerana, that has relatively recently been detected in the western honey bee, Apis mellifera. Using a Proboscis Extension Response assay, we found that A. cerana was significantly more likely than A. mellifera to avoid sucrose solutions with concentrations above 1 x 10(6) N. ceranae spores per mL. However, neither species avoided the sucrose solutions with lower N. ceranae concentrations, similar to those detected on flowers
Preservice teachers’ adaptations to tensions associated with the edTPA during its early implementation in New York and Washington states
The edTPA is a teaching performance assessment (TPA) that the states of New York and Washington implemented as a licensure requirement in 2013. While TPAs are not new modes of assessment, New York and Washington are the first states to use the edTPA specifically as a compulsory, high-stakes policy lever in an effort to strengthen the quality and accountability of teachers and teacher educators. This study examines 24 New York and Washington teaching candidates’ experiences with the edTPA during its first year of consequential use for state certification. The data, drawn from qualitative interviews that were part of a larger mixed-methods study, reveal that preservice teachers had to mediate several tensions associated with the edTPA’s dual role as a formative assessment tool and a licensure mechanism. In this paper, we identify those tensions, describe candidates’ efforts to mediate them, and discuss the extent to which that mediation process may or may not contribute to the improvement of teachers’ practices. Given the edTPA’s positioning in a policy context – specifically, the potential for the assessment’s locus of control, high stakes, and opaque rating process to distort the procedures it is intended to measure – the paper concludes with recommendations for teacher education programs aimed at capitalizing on the edTPA’s benefits and mitigating its unproductive tensions.
Negotiating mathematical goals in coaching conversations
Content-focused coaching aims to focus the coach-teacher conversations on the quality of mathematical goals and associated activities while co-planning a lesson. The coach’s role is to support the teacher to articulate a mathematical goal that represents an important mathematical idea, to plan activities in support of that goal, and to anticipate how students will respond to the mathematical activities. We use a framework that emphasizes the dialogic and mediated nature of the coach-teacher conversations. We found that coaching conversations focused primarily on instrumental aspects of lesson planning and only less so on deeper articulations of content, and we found differences across coaches’ practices. The findings provide nuance to empirical findings of coach-teacher conversations
Materials have driven the historical development of the Tennis Racket
© 2019 by the authors. The tennis racket has developed since the origins of Lawn Tennis in the 1870s. This study investigated how the tennis racket developed from 1874 to 2017, using measurements and material classifications for 525 samples. Racket measurements covered geometric, inertial and dynamic properties, and the number of strings. Rackets predating 1970 were mainly wooden, and typically characterised by head areas below 0.05 m2, masses over 350 g and natural frequencies below 120 Hz. Rackets from the 1970s were made from wood, metal and fibre-polymer composites, with most postdating 1980 made from fibre-polymer composites with a larger head, lower mass and higher natural frequency than their predecessors. Principal component analysis was used to reduce the dimensionality of the number of variables. Principal component one (PCA1) accounted for 35% of the variance in the measured racket properties, and was found to be significantly affected by material. Head width was best correlated with principal component one (r = 0.897, p < 0.001), followed by head length (r = 0.841, p < 0.001) and natural frequency (r = 0.813, p < 0.001). Early rackets were constrained by the limitations of wood, and the move to composites, which began in the 1970s, allowed this observed increase in head size and natural frequency. As material development has been a major driver of racket design in the past, we propose that new materials and manufacturing techniques, like additively manufactured composites, could further improve the tennis racket. The measurement techniques described here can be used to monitor developments in racket design
Upstaging nodal status in colorectal cancer using ex vivo fluorescence sentinel lymph node mapping: preliminary results
Background: Sentinel lymph node (SLN) mapping using near-infrared fluorescence (NIRF) imaging is a recent technique to improve nodal staging in several tumors. The presence of colorectal cancer (CRC) micro-metastases has recently been defined as N1 disease and no longer as N1mi, determining the need for adjuvant chemotherapy. In CRC, the reported rate of SLN micro-metastases detected by ultrastaging techniques is as high as 30%. The aim of this prospective study is to report the preliminary results of the sensitivity analysis of NIRF imaging for ex vivo SLN mapping and the research of micro-metastases in CRC, in patients with node-negative disease (NND). Material and methods: On the specimen of 22 CRC patients, 1 mL of ICG (5 mg/mL) was injected submucosally around the tumor to identify SLNs. NND SLNs were further investigated with ultrastaging techniques. Results: Three-hundred and sixty-three lymph nodes were retrieved (59 SLNs; mean per case: 2.7). The detection, sensitivity and false-negative rate were 100%, 100% and 0% respectively. Ultrastaging investigations showed no micro-metastases in the NND SLNs. Conclusions: The ex vivo SLN fluorescence-based detection in CRC was confirmed to be easy to perform and reliable. In this preliminary results report of an ongoing study, the SLN assay was congruent with the nodal status, as confirmed by histological investigations
Single view silhouette fitting techniques for estimating tennis racket position
Stereo camera systems have been used to track markers attached to a racket, allowing its position to be obtained in three-dimensional (3D) space. Typically, markers are manually selected on the image plane, but this can be time-consuming. A markerless system based on one stationary camera estimating 3D racket position data is desirable for research and play. The markerless method presented in this paper relies on a set of racket silhouette views in a common reference frame captured with a calibrated camera and a silhouette of a racket captured with a camera whose relative pose is outside the common reference frame. The aim of this paper is to provide validation of these single view fitting techniques to estimate the pose of a tennis racket. This includes the development of a calibration method to provide the relative pose of a stationary camera with respect to a racket. Mean static racket position was reconstructed to within ±2 mm. Computer generated camera poses and silhouette views of a full size racket model were used to demonstrate the potential of the method to estimate 3D racket position during a simplified serve scenario. From a camera distance of 14 m, 3D racket position was estimated providing a spatial accuracy of 1.9 ± 0.14 mm, similar to recent 3D video marker tracking studies of tennis
The development of a low cost 3D surface imaging system to measure breast volume: defining minimum standards using an adapted Delphi consensus study
Breast reconstructive surgery has become an accepted part of the patient pathway for breast cancer patients requiring mastectomy. Yet the UK National Mastectomy and Breast Reconstruction Audit (2011)(1) identified that one in four women were not satisfied with how their unclothed breasts looked after delayed reconstructive surgery. Women with an intact breast after surgery are generally referred for whole breast irradiation, radiotherapy increases the risk of these women developing breast oedema
Tumor-associated antigen human chorionic gonadotropin beta contains numerous antigenic determinants recognized by in vitro-induced CD8+ and CD4+ T lymphocytes.
The beta subunit of human chorionic gonadotropin (hCG beta) is markedly overexpressed by neoplastic cells of differing histological origin including those present in colon, breast, prostate and bladder tumors. We have previously shown that some patients with hCG beta-producing urothelial tumors have circulating T cells that proliferate in response to hCG beta. To make a comprehensive study of hCG beta as a potential target for cancer immunotherapy, we investigated whether hCG beta peptides could induce CD4+ or CD8+ T-cell responses in vitro. By stimulating peripheral blood mononuclear cells (PBMCs) from three donors with mixtures of overlapping 16-mer synthetic peptides analogous to portions of either the hCG beta 20-71 or the hCG beta 102-129 region, we established six CD4+ T-cell lines that proliferated specifically in response to five distinct determinants located within these two hCG beta regions. Three antigenic determinants (hCG beta 52-67, 106-121 and 114-125) were presented by HLA-DR molecules, while the two other antigenic determinants (hCG beta 48-63 and 56-67) were presented by HLA-DQ molecules. Interestingly, one T-cell line specific for peptide hCG beta 106-121 recognized hCG beta peptides comprising, at position 117, either an alanine or an aspartic acid residue, with the latter residue being present within the protein expressed by some tumor cells. In addition, three other hCG beta-derived peptides that exhibited HLA-A*0201 binding ability were able to stimulate CD8+ cytotoxic T cells from two HLA-A*0201 donors. These three immunogenic peptides corresponded to regions hCG beta 40-48, hCG beta 44-52 and hCG beta 75-84. Our results indicate that the tumor-associated antigen hCG beta possesses numerous antigenic determinants liable to stimulate CD4+ and CD8+ T lymphocytes, and might thus be an effective target antigen for the immunotherapy of hCG beta-producing tumors
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Highly efficient separation of actinides from lanthanides by a phenanthroline-derived bis-triazine ligand
The synthesis, lanthanide complexation, and solvent ex- traction of actinide(III) and lanthanide(III) radiotracers from nitric acid solutions by a phenanthroline-derived quadridentate bis-triazine ligand are described. The ligand separates Am(III) and Cm(III) from the lanthanides with remarkably high efficiency, high selectivity, and fast extraction kinetics compared to its 2,2'-bipyridine counterpart. Structures of the 1:2 bis-complexes of the ligand with Eu(III) and Yb(III) were elucidated by X-ray crystallography and force field calculations, respec-tively. The Eu(III) bis-complex is the first 1:2 bis-complex of a quadridentate bis-triazine ligand to be characterized by crystallography. The faster rates of extraction were verified by kinetics measurements using the rotating membrane cell technique in several diluents. The improved kinetics of metal ion extraction are related to the higher surface activity of the ligand at the phase interface. The improvement in the ligand's properties on replacing the bipyridine unit with a phenanthroline unit far exceeds what was anticipated based on ligand design alone
Creating drag and lift curves from soccer trajectories
Trajectory analysis is an alternative to using wind tunnels to measure a soccer
balls aerodynamic properties. It has advantages over wind tunnel testing such as being
more representative of game play. However, previous work has not presented a method that
produces complete, speed -dependent drag and lift coefficients. Four high-speed cameras in
stereo-calibrated pairs were used to measure the spatial co-ordinates for 29 separate soccer
trajectories. Those trajectories span a range of launch speeds from 9.3 m/s to 29.9 m/s. That
range encompasses low-speed laminar flow of air over a soccer ball, through the drag crises
where air flow is both laminar and turbulent, and up to high-speed turbulent air flow. Results
from trajectory analysis were combined to give speed-dependent drag and lift coefficient
curves for the entire range of speeds found in the 29 trajectories. Average root mean square
error between measured and modelled trajectory was 0.028 m horizontally and 0.034 m
vertically. The drag and lift crises can be observed in the plots of drag and lift coefficients
respectively
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