60419 research outputs found
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Uncovering the Impact of Triadic Relationships within a Team on Job Performance: An Application of Balance Theory in Predicting Feedback-Seeking Behavior
No full textAlthough a great deal of knowledge has accumulated about dyadic relationships (i.e., leader-member exchange (LMX) or team-member exchange (TMX)) within a team, employee behaviors that involve triadic relationships among focal employees, leaders, and teammates have seldom been investigated. Using Balance Theory, which describes triadic relationships from a power-dependence perspective, in the current study, we explore how the interplay of LMX, TMX, and peers’ LMX jointly impact employees’ feedback-seeking behavior (FSB) and subsequent job performance. By conducting a multilevel moderated polynomial regression on three-wave, multi-source data from 147 team members and their leaders (from 45 work teams), we found that the incongruence between LMX and TMX facilitates FSB when peers’ LMX or task interdependence is high. We also found an asymmetrical incongruence effect concerning the way in which individuals are more likely to seek feedback when LMX is worse than TMX, compared with when LMX is better than TMX. This differential effect is stronger when peers’ LMX or task interdependence is high. The interplay of LMX, TMX, peers’ LMX, and task interdependence eventually has an indirect effect on job performance through FSB. The results from a follow-up study of 270 employees from 77 teams further confirm our predictions about the mechanism of Balance Theory. Specifically, the results indicate that when peers’ LMX is high, the incongruence between LMX and TMX decreases employees’ psychological safety
The Pragmatics of Intimacy
No full textThis study examines the ways in which multiple modern communication technologies facilitate, across time and space, the maintenance of a close interpersonal relationship between two best friends. The analysis, which focuses mainly on the openings and closings of the different types of communications, reveals a tendency for the friends to shorten openings and extend closings. However, this is possible only if the friends are fully aware of, and care about, the practical, social and emotional details of each other’s lives during periods of absence. The concomitant linguistic behaviours in their interpersonal interactions could be described as a kind of pragmatics of intimacy which cannot be achieved without the explicit and practical demonstration of that mutual care and concern
Rate-splitting precoding for future point-to-multipoint communication.
No full textAs an alternative to classic point-to-point (PTP) unicast transmission, point-to-multipoint (PTM) broadcast/multicast transmission offers simultaneous transmission of the same content to multiple receivers, using just a fixed amount of radio resources for a given coverage area. Such transmission capability has been kept enhancing in the legacy 4th Generation long-term evolution (4G-LTE), namely evolved multimedia broadcast multicast service (eMBMS). As the current multicast systems in the eMBMS use time division multiplexing (TDM) to separate different transmissions, which, however, can cause inefficient utilization of scarce radio resources, and even becomes an impediment in developing such systems to meet new use cases in the 5th generation (5G). To tackle this problem, we proposed a Rate-Splitting (RS) based precoding design to improve the multicast system performances.
However, as an emerging precoding technology, various theoretical questions, and practical issues remain to be abundantly investigated. To this end, the overall objective of the proposed research is to first investigate the eMBMS system with both LTE and new radio (NR) specifications and then propose effective approaches i.e., Rate-Splitting to improve the PTM system performance.
Firstly, we conduct a study of the eMBMS technique from the physical layer perspective, comparing between the two major techniques of the eMBMS i.e. multicast broadcast single frequency network (MBSFN) and single cell point to multipoint (SC-PTM), via link-level simulations. A selection of key performance indicators (KPIs) defined by the ITU-R for the IMT-2020 evaluation has been evaluated on data channel, e.g., physical downlink shared channel (PDSCH). This performance evaluation serves as a benchmark for comparison with a potential 5G broadcast solution. Furthermore, we investigate the error performance, mobility tolerance, and coverage of the control channel, e.g., physical downlink control channel (PDCCH) based on both LTE and NR specifications.
Secondly, we target at an overloaded downlink multicarrier multigroup multicast system with RS under the assumption of Gaussian input, looking into both the achievable rate and error performance. Two optimization methods are provided, i.e., weight minimum mean square error (WMMSE) and successive convex approximation (SCA), to jointly optimize the precoding matrix and subcarrier allocation. Simulation results reveal that RS provides a substantial user experience improvement compared to the state-of-the-art multicast transmission schemes.
Thirdly, we investigate the RS under the constraint of finite-alphabet constellations. We formulate an optimization problem that maximizes the weighted sum rate of the RS system and solve the problem with an iterative gradient descent algorithm to find the optimal precoder. The simulation results show that compared to the traditional linear precoding scheme, RS can reach the maximum achievable sum-rate with a less transmit power. Then, based on the obtained RS precoder with corresponding constellation inputs, we look into the error performance, e.g., bit error rate (BER) and symbol error rate (SER) of the proposed RS scheme, with channel coding and iterative soft detection and decoding. On top of the performance improvement in terms of achievable rate, the proposed RS scheme also has a better error performance compared to other considered linear precoding schemes in overloaded scenarios
Reducing postprandial glucose in dietary intervention studies and the magnitude of the effect on diabetes-related risk factors: a systematic review and meta-analysis
No full textPurpose: Reducing postprandial hyperglycemia has beneficial effects on diabetesrelated risk factors, but the magnitude of the reduction needed to achieve such an effect is unknown. To quantify the relationship of acute glucose and insulin postprandial responses with longer-term effects on diabetes-related risk factors by performing a systematic review and meta-analysis of dietary intervention studies. Methods: We systematically searched EMBASE and MEDLINE. Dietary intervention studies among any human population aiming to reduce postprandial glycaemia, with actual measures of postprandial glucose (PPG) and/or insulin (PPI) as acute exposures (incremental area under the curve, iAUC) as well as markers of glucose metabolism (fasting glucose, HbA1c) and insulin sensitivity (fasting insulin, HOMA-IR) after at least 4 weeks of diet intervention as outcomes, were included. Meta-analyses were performed for the effects on acute exposures and on diabetes-related risk factors. The relationship between changes in acute exposures and changes in risk factor outcomes was estimated by meta-regression analyses. Results: Out of the 13004 screened papers, 14 papers with 14 comparisons were included in the quantitative analysis. The dietary interventions acutely reduced mean PPG (mean difference (MD), -0.27 mmol/l; 95% CI, -0.41 to -0.14) but not mean PPI (MD, -7.47 pmol/l; 95% CI, -16.79 to 1.86). No significant overall effects on fasting glucose and insulin. HbA1c was reduced by -0.20% (95%CI -0.35 to -0.05). Changes in acute PPG were significantly associated with changes in fasting plasma glucose (FPG) (per 10% change in PPG: β = 0.085 (95% CI, 0.003, 0.167), k=14), but not with fasting insulin (β = 1.20 (95% CI, -0.32, 2.71), k=12). Changes in acute PPI were not associated with changes in FPG (per 10% change in PPI: β = -0.017 (95% CI, -0.056, 0.022), k=11). Conclusions: Only a limited number of postprandial glucose lowering dietary intervention studies measured acute postprandial exposures to PPG/PPI during the interventions. In this small heterogeneous set of studies, an association was found between the magnitude of the acute postprandial responses and the change in fasting glucose but no other outcomes. More studies are needed to quantify the relationship between acute postprandial changes and long-term effects on risk factors
A closer look at the spur, blob, wiggle, and gaps in GD-1
No full textThe GD-1 stream is one of the longest and coldest stellar streams discovered to date, and one of the best objects for constraining the dark matter properties of the Milky Way. Using data from Gaia DR2 we study the proper motions, distance, morphology and density of the streamto uncover small scale perturbations. The proper motion cleaned data shows a clear distance gradient across the stream, ranging from 7 to 12 kpc. However, unlike earlier studies thatfound a continuous gradient, we uncover a distance minimum atφ1≈-50 deg, after which the distance increases again. We can reliably trace the stream between -85< φ1<15 deg, show-ing an even further extent to GD-1 beyond the earlier extension of Price-Whelan & Bonaca(2018). We constrain the stream track and density using a Boolean matched filter approachand find three large under densities and find significant residuals in the stream track lining upwith these gaps. In particular, a gap is visible atφ1=-3 deg, surrounded by a clear sinusoidal wiggle. We argue that this wiggle is due to a perturbation since it has the wrong orientationto come from a progenitor. We compute a total initial stellar mass of the stream segment of 1.58±0.07×104M. With the extended view of the spur in this work, we argue that the spurmay be unrelated to the adjacent gap in the stream. Finally, we show that an interaction withthe Sagittarius dwarf can create features similar to the spur
Full-Reference Stereoscopic Video Quality Assessment Using a Motion Sensitive HVS Model
No full textStereoscopic video quality assessment has become
a major research topic in recent years. Existing stereoscopic video quality metrics are predominantly based on stereoscopic image quality metrics extended to the time domain via for example temporal pooling. These approaches do not explicitly consider the motion sensitivity of the Human Visual System (HVS). To address this limitation, this paper introduces a novel HVS model inspired by physiological findings characterising the
motion sensitive response of complex cells in the primary visual cortex (V1 area). The proposed HVS model generalises previous HVS models, which characterised the behaviour of simple and complex cells but ignored motion sensitivity, by estimating optical flow to measure scene velocity at different scales and orientations.
The local motion characteristics (direction and amplitude) are used to modulate the output of complex cells. The model is applied to develop a new type of full-reference stereoscopic video quality metrics which uniquely combine non-motion sensitive and motion sensitive energy terms to mimic the response of the HVS. A tailored two-stage multi-variate stepwise regression algorithm is introduced to determine the optimal contribution of
each energy term. The two proposed stereoscopic video quality metrics are evaluated on three stereoscopic video datasets. Results indicate that they achieve average correlations with subjective
scores of 0.9257 (PLCC), 0.9338 and 0.9120 (SRCC), 0.8622
and 0.8306 (KRCC), and outperform previous stereoscopic video
quality metrics including other recent HVS-based metrics
Stochastic Gradient Langevin dynamics for joint parameterization of tracer kinetic models, input functions, and T1 relaxation-times from undersampled k-space DCE-MRI
No full textDynamic Contrast Enhanced (DCE) Magnetic Resonance Imaging (MRI) is an important diagnostic technique that can quantify the structure and function of microvasculature processes, using T1 relaxation times and tracer kinetic maps. However, a series of methodological limitations affect both the accuracy and standardisation of the quantified maps, and consequently their diagnostic ability. The main methodological challenge in the quantification of tracer kinetics is a multi-parameter optimization, with correlated parameters that have different scales, which results in local minima particularly when measurements are highly undersampled. This work suggests a novel data driven optimization scheme, based on a variation of the Stochastic Gradient Langevin dynamics (SGLD) Markov chain Monte Carlo algorithm, which combines stochastic gradient descent and Langevin dynamics. The proposed SGDL algorithm avoided local minima and accurately quantified proton density, T1 relaxation times and tracer kinetics. Joint direct parameterization significantly benefited the quantification of proton density, T1 relaxation times, and the selection of a suitable tracer kinetic model per tissue type. Model based arterial and portal vein input functions were automatically determined during the joint direct parameterization. Observations made on simulated fully and highly undersampled liver DCE MRI data were confirmed on acquired clinical data
A PERIOD3 variable-number-tandem-repeat polymorphism modulates melatonin treatment response in Delayed Sleep-Wake Phase Disorder
No full textWe examined whether a polymorphism of the PERIOD3 gene (PER3; rs57875989) modulated the sleep promoting effects of melatonin in Delayed Sleep-Wake Phase Disorder (DSWPD). One hundred and four individuals (53 males; 29.4±10.0 years) with DSWPD and a delayed dim light melatonin onset (DLMO) collected buccal swabs for genotyping (PER34/4 n=43; PER3 5 allele [heterozygous and homozygous] n=60). Participants were randomised to placebo or 0.5mg melatonin taken 1 hour before desired bedtime (or ~ 1.45 h before DLMO), with sleep attempted at desired bedtime (4 weeks; 5-7 nights/week). We assessed sleep (diary and actigraphy), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Patient-Reported Outcomes Measurement Information System (PROMIS: Sleep Disturbance, Sleep-Related Impairment), Sheehan Disability Scale (SDS), and Patient- and Clinician-Global Improvement (PGI-C, CGI-C). Melatonin treatment response on actigraphic sleep onset time did not differ between genotypes. For PER34/4 carriers, self-reported sleep onset time was advanced by a larger amount and sleep onset latency (SOL) was shorter in melatonin-treated patients compared to those receiving placebo (P=0.008), while actigraphic sleep efficiency in the first third of the sleep episode (SE T1) did not differ. For PER3 5 carriers, actigraphic SOL and SE T1 showed a larger improvement with melatonin (P<0.001). Melatonin improved ISI (P=0.005), PROMIS Sleep Disturbance (P<0.001) and Sleep-Related Impairment (P=0.017), SDS (P=0.019), PGI-C (P=0.028), and CGI-C (P=0.016) in PER34/4 individuals only. Melatonin did not advance circadian phase. Overall, PER34/4 DSWPD patients have a greater response to melatonin treatment. PER3 genotyping may therefore improve DSWPD patient outcomes
That’s private! Understanding travelers’ privacy concerns and online data disclosure
No full textAgainst the backdrop of advancements in technology and its deployment by companies and governments to collect sensitive personal information, information privacy has become an issue of great interest for academics, practitioners, and the general public. The travel and tourism industry has been pioneering the collection and use of biometric data for identity verification. Yet, privacy research focusing on the travel context is scarce. This study developed a valid measurement of Travelers’ Online Privacy Concerns (TOPC) through a series of empirical studies: pilot (N=277) and cross-validation (N=287). TOPC was then assessed for its predictive validity in its relationships with trust, risk, and intention to disclose four types of personal data: biometric, identifiers, biographic, and behavioral data (N=685). Results highlight the role of trust in mitigating the relationship between travelers’ privacy concerns and data disclosure. This study provides valuable contribution to research and practice on data privacy in travel
RUNNING HEAD: Activity-oriented questions in student focus groups
No full textSurfacing student voices is of upmost importance in higher education institutions. However, use of large-scale student surveys may not represent the most effective method of eliciting meaningful student perspectives. Focus groups have the potential to elicit a more authentic student voice through greater engagement with students. Furthermore, activities incorporated into these discussions may be beneficial in the higher education context. The aim of this manuscript is to explore the use of activities in focus group discussions within a project focussed on students’ use of feedback. We draw on focus group discussion transcripts, debrief transcripts, field notes and activity artefacts to demonstrate how activities can be incorporated into focus group discussions. The findings indicate several benefits to using activities in higher education focus group discussions. As such, a framework to guide use of activities, based on the purpose of the focus groups, is provided within the context of higher education research
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