2,378 research outputs found
The effects of peer judgements on teamwork and self-assessment ability in collaborative group work
A crucial determinant of the success or failure of collaborative group work is the effect of peer feedback interventions on learning. Research exploring such effects on developing soft skills is sparse. This study seeks to address whether peer feedback leads to enhanced teamwork behaviour and self-assessment ability, two skills highly sought after by employers. Specifically, this study examines the direct effect of formative performance rating and the mediating effect of praise and criticism in peer feedback messages on achievement in teamwork and self-assessment skills. The sample consists of quantitative and qualitative data from 98 students enrolled in business programmes using a particular form of collaborative group work. The paper finds a direct positive relationship between formative performance rating and summative self-assessment ability. It also finds that praise negatively mediates the relationship between formative performance rating and summative teamwork. Further analyses suggest that a significant proportion of comments provided is past- rather than future-oriented. Potential strategies to overcome the limitations of current practices are discussed
Generating entanglement between quantum dots with different resonant frequencies based on Dipole Induced Transparency
We describe a method for generating entanglement between two spatially
separated dipoles coupled to optical micro-cavities.
The protocol works even when the dipoles have different resonant frequencies
and radiative lifetimes.
This method is particularly important for solid-state emitters, such as
quantum dots, which suffer from large inhomogeneous broadening. We show that
high fidelities can be obtained over a large dipole detuning range without
significant loss of efficiency. We analyze the impact of higher order photon
number states and cavity resonance mismatch on the performance of the protocol
Energy Efficient Clustering and Routing in Mobile Wireless Sensor Network
A critical need in Mobile Wireless Sensor Network (MWSN) is to achieve energy
efficiency during routing as the sensor nodes have scarce energy resource. The
nodes' mobility in MWSN poses a challenge to design an energy efficient routing
protocol. Clustering helps to achieve energy efficiency by reducing the
organization complexity overhead of the network which is proportional to the
number of nodes in the network. This paper proposes a novel hybrid multipath
routing algorithm with an efficient clustering technique. A node is selected as
cluster head if it has high surplus energy, better transmission range and least
mobility. The Energy Aware (EA) selection mechanism and the Maximal Nodal
Surplus Energy estimation technique incorporated in this algorithm improves the
energy performance during routing. Simulation results can show that the
proposed clustering and routing algorithm can scale well in dynamic and energy
deficient mobile sensor network.Comment: 9 pages, 4 figure
Crowded-Field Astrometry with the Space Interferometry Mission - I. Estimating the Single-Measurement Astrometric Bias Arising from Confusion
The accuracy of position measurements on stellar targets with the future
Space Interferometry Mission (SIM) will be limited not only by photon noise and
by the properties of the instrument (design, stability, etc.) and the overall
measurement program (observing strategy, reduction methods, etc.), but also by
the presence of other "confusing" stars in the field of view (FOV). We use a
simple "phasor" model as an aid to understanding the main effects of this
"confusion bias" in single observations with SIM. This analytic model has been
implemented numerically in a computer code and applied to a selection of
typical SIM target fields drawn from some of the Key Projects already accepted
for the Mission. We expect that less than 1% of all SIM targets will be
vulnerable to confusion bias; we show that for the present SIM design,
confusion may be a concern if the surface density of field stars exceeds 0.4
star/arcsec^2. We have developed a software tool as an aid to ascertaining the
possible presence of confusion bias in single observations of any arbitrary
field. Some a priori knowledge of the locations and spectral energy
distributions of the few brightest stars in the FOV is helpful in establishing
the possible presence of confusion bias, but the information is in general not
likely to be available with sufficient accuracy to permit its removal. We
discuss several ways of reducing the likelihood of confusion bias in crowded
fields. Finally, several limitations of the present semi-analytic approach are
reviewed, and their effects on the present results are estimated. The simple
model presented here provides a good physical understanding of how confusion
arises in a single SIM observation, and has sufficient precision to establish
the likelihood of a bias in most cases.Comment: 28 pages, 20 figures, 1 table; to appear in December 2007 issue of
PAS
Does the use of summative peer assessment in collaborative group work inhibit good judgement?
The accuracy and consistency of peer marking, particularly when students have the power to reward (or penalise) during formative and summative assessment regimes, is largely unknown. The objective of this study is to evaluate students’ ability and behaviour in marking their peers’ teamwork performance in a collaborative group assessment context both when the mark is counted and not counted towards their final grade. Formative and summative assessment data were obtained from 98 participants in anonymous self and peer assessment of team members’ contributions to a group assessment in business courses. The findings indicate that students are capable of accurately and consistently judging their peers’ performance to a large extent, especially in the formative evaluation of the process component of group work. However, the findings suggest significant peer grading bias when peer marks contribute to final grades. Overall, findings suggest that students are reluctant to honestly assess their peers when they realise that their actions can penalise non-contributing students. This raises questions about the appropriateness of using peer marks for summative assessment purposes. To overcome the problems identified, this paper proposes a number of measures to guide educators in effectively embedding summative peer assessment in a group assessment contex
A Generative-Discriminative Basis Learning Framework to Predict Clinical Severity from Resting State Functional MRI Data
We propose a matrix factorization technique that decomposes the resting state
fMRI (rs-fMRI) correlation matrices for a patient population into a sparse set
of representative subnetworks, as modeled by rank one outer products. The
subnetworks are combined using patient specific non-negative coefficients;
these coefficients are also used to model, and subsequently predict the
clinical severity of a given patient via a linear regression. Our
generative-discriminative framework is able to exploit the structure of rs-fMRI
correlation matrices to capture group level effects, while simultaneously
accounting for patient variability. We employ ten fold cross validation to
demonstrate the predictive power of our model on a cohort of fifty eight
patients diagnosed with Autism Spectrum Disorder. Our method outperforms
classical semi-supervised frameworks, which perform dimensionality reduction on
the correlation features followed by non-linear regression to predict the
clinical scores
Does the Superior Colliculus Control Perceptual Sensitivity or Choice Bias during Attention? Evidence from a Multialternative Decision Framework
Distinct networks in the forebrain and the midbrain coordinate to control spatial attention. The critical involvement of the superior colliculus (SC)—the central structure in the midbrain network—in visuospatial attention has been shown by four seminal, published studies in monkeys (Macaca mulatta) performing multialternative tasks. However, due to the lack of a mechanistic framework for interpreting behavioral data in such tasks, the nature of the SC's contribution to attention remains unclear. Here we present and validate a novel decision framework for analyzing behavioral data in multialternative attention tasks. We apply this framework to re-examine the behavioral evidence from these published studies. Our model is a multidimensional extension to signal detection theory that distinguishes between two major classes of attentional mechanisms: those that alter the quality of sensory information or “sensitivity,” and those that alter the selective gating of sensory information or “choice bias.” Model-based simulations and model-based analyses of data from these published studies revealed a converging pattern of results that indicated that choice-bias changes, rather than sensitivity changes, were the primary outcome of SC manipulation. Our results suggest that the SC contributes to attentional performance predominantly by generating a spatial choice bias for stimuli at a selected location, and that this bias operates downstream of forebrain mechanisms that enhance sensitivity. The findings lead to a testable mechanistic framework of how the midbrain and forebrain networks interact to control spatial attention
Initiating haemodialysis twice-weekly as part of an incremental programme may protect residual kidney function
© The Author(s) 2018. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.Background: Initiating twice-weekly haemodialysis (2×HD) in patients who retain significant residual kidney function (RKF) may have benefits. We aimed to determine differences between patients initiated on twice- and thrice-weekly regimes, with respect to loss of kidney function, survival and other safety parameters. Methods: We conducted a single-centre retrospective study of patients initiating dialysis with a residual urea clearance (KRU) of ≥3 mL/min, over a 20-year period. Patients who had 2×HD for ≥3 months during the 12 months following initiation of 2×HD were identified for comparison with those dialysed thrice-weekly (3×HD). Results: The 2×HD group consisted of 154 patients, and the 3×HD group 411 patients. The 2×HD patients were younger (59 ± 15 versus 62 ± 15 years: P = 0.014) and weighed less (70 ± 16 versus 80 ± 18 kg: P < 0.001). More were females (34% versus 27%: P = 0.004). Fewer had diabetes (25% versus 34%: P = 0.04) and peripheral vascular disease (PVD) (13% versus 23%: P = 0.008). Baseline KRU was similar in both groups (5.3 ± 2.4 for 2 × HD versus 5.1 ± 2.8 mL/min for 3 × HD: P = 0.507). In a mixed effects model correcting for between-group differences in comorbidities and demographics, 3×HD was associated with increased rate of loss of KRU and separation of KRU. In separate mixed effects models, group (2×HD versus 3×HD) was not associated with differences in serum potassium or phosphate, and the groups did not differ with respect to total standard Kt/V. Survival, adjusted for age, gender, weight, baseline KRU and comorbidity (prevalence of diabetes, cardiac disease, PVD and malignancy) was greater in the 2×HD group (hazard ratio 0.755: P = 0.044). In sub-analyses, the survival benefit was confined to women, and those of less than median bodyweight. Conclusion: 2×HD initiation as part of an incremental programme with regular monthly monitoring of KRU was safe and associated with a reduced rate of loss of RKF early after dialysis initiation and improved survival. Randomized controlled trials of this approach are indicated.Peer reviewedFinal Accepted Versio
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