Do social cues in instructional videos affect attention allocation, perceived cognitive load, and learning outcomes under different visual complexity conditions?

Background:There are only few guidelines on how instructional videos should be designed to optimize learning. Recently, the effects of social cues on attention allocation and learning in instructional videos have been investigated. Due to inconsistent results, it has been suggested that the visual complexity of a video influences the effect of social cues on learning.Objectives:Therefore, this study compared the effects of social cues (i.e., gaze & gesture) in low and high visual complexity videos on attention, perceived cognitive load,and learning outcomes.Methods:Participants (N=71) were allocated to a social cue or no social cue condition and watched both a low and a high visual complexity video. After each video, participants completed a knowledge test.Results and Conclusions: Results showed that participants looked faster at referenced information and had higher learning outcomes in the low visual complexity condition. Social cues did not affect any of the dependent variables, except when including prior knowledge in the analysis: In this exploratory analysis, the inclusion of gaze and gesture cues in the videos did lead to better learning outcomes.Takeaways: Our results show that the visual complexity of instructional videos and prior knowledge are important to take into account in future research on attention and learning from instructional videos

The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory

The Photodetector Array Camera and Spectrometer (PACS) is one of the three science instruments on ESA's far infrared and submillimetre observatory. It employs two Ge:Ga photoconductor arrays (stressed and unstressed) with 16x25 pixels, each, and two filled silicon bolometer arrays with 16x32 and 32x64 pixels, respectively, to perform integral-field spectroscopy and imaging photometry in the 60-210\mu\ m wavelength regime. In photometry mode, it simultaneously images two bands, 60-85\mu\ m or 85-125\mu\m and 125-210\mu\ m, over a field of view of ~1.75'x3.5', with close to Nyquist beam sampling in each band. In spectroscopy mode, it images a field of 47"x47", resolved into 5x5 pixels, with an instantaneous spectral coverage of ~1500km/s and a spectral resolution of ~175km/s. We summarise the design of the instrument, describe observing modes, calibration, and data analysis methods, and present our current assessment of the in-orbit performance of the instrument based on the Performance Verification tests. PACS is fully operational, and the achieved performance is close to or better than the pre-launch predictions

The association between frailty and MRI features of cerebral small vessel disease.

Frailty is a common syndrome in older individuals that is associated with poor cognitive outcome. The underlying brain correlates of frailty are unclear. The aim of this study was to investigate the association between frailty and MRI features of cerebral small vessel disease in a group of non-demented older individuals. We included 170 participants who were classified as frail (n = 30), pre-frail (n = 85) or non-frail (n = 55). The association of frailty and white matter hyperintensity volume and shape features, lacunar infarcts and cerebral perfusion was investigated by regression analyses adjusted for age and sex. Frail and pre-frail participants were older, more often female and showed higher white matter hyperintensity volume (0.69 [95%-CI 0.08 to 1.31], p = 0.03 respectively 0.43 [95%-CI: 0.04 to 0.82], p = 0.03) compared to non-frail participants. Frail participants showed a non-significant trend, and pre-frail participants showed a more complex shape of white matter hyperintensities (concavity index: 0.04 [95%-CI: 0.03 to 0.08], p = 0.03; fractal dimensions: 0.07 [95%-CI: 0.00 to 0.15], p = 0.05) compared to non-frail participants. No between group differences were found in gray matter perfusion or in the presence of lacunar infarcts. In conclusion, increased white matter hyperintensity volume and a more complex white matter hyperintensity shape may be structural brain correlates of the frailty phenotype

Small but crucial : the novel small heat shock protein Hsp21 mediates stress adaptation and virulence in Candida albicans

Peer reviewedPublisher PD

Hematopoietic Stem Cells Contribute to Lymphatic Endothelium

Although the lymphatic system arises as an extension of venous vessels in the embryo, little is known about the role of circulating progenitors in the maintenance or development of lymphatic endothelium. Here, we investigated whether hematopoietic stem cells (HSCs) have the potential to give rise to lymphatic endothelial cells (LEC). mice resulted in the incorporation of donor-derived LEC into the lymphatic vessels of spontaneously arising intestinal tumors.Our results indicate that HSCs can contribute to normal and tumor associated lymphatic endothelium. These findings suggest that the modification of HSCs may be a novel approach for targeting tumor metastasis and attenuating diseases of the lymphatic system

Post-Exposure Vaccination Improves Gammaherpesvirus Neutralization

Herpesvirus carriers transmit infection despite making virus-specific antibodies. Thus, their antibody responses are not necessarily optimal. An important question for infection control is whether vaccinating carriers might improve virus neutralization. The antibody response to murine gamma-herpesvirus-68 (MHV-68) blocks cell binding, but fails to block and even enhances an IgG Fc receptor-dependent infection of myeloid cells. Viral membrane fusion therefore remains intact. Although gH/gL-specific monoclonal antibodies can block infection at a post-binding step close to membrane fusion, gH/gL is a relatively minor antibody target in virus carriers. We show here that gH/gL-specific antibodies can block both Fc receptor-independent and Fc receptor-dependent infections, and that vaccinating virus carriers with a gH/gL fusion protein improves their capacity for virus neutralization both in vitro and in vivo. This approach has the potential to reduce herpesvirus transmission

Outcome of Microscopic Incomplete Resection (R1) of Colorectal Liver Metastases in the Era of Neoadjuvant Chemotherapy

Background: Data from patients with colorectal liver metastases (CRLM) who received neoadjuvant chemotherapy before resection were reviewed and evaluated to see whether neoadjuvant chemotherapy influences the predictive outcome of R1 resections (margin is 0 mm) in patients with CRLM. Methods: Between January 2000 and December 2008, all consecutive patients undergoing liver resection for CRLM were analyzed. Patients were divided into those who did and did not receive neoadjuvant chemotherapy. The outcome after R0 (tumor-free margin >0 mm) and R1 (tumor-free margin 0 mm) resection was compared. Results: A total of 264 were eligible for analysis. Median follow-up was 34 months. Patients without chemotherapy showed a significant difference in median disease-free survival (DFS) after R0 or R1 resection: 17 [95% confidence interval (CI) 10-24] months versus 8 (95% CI 4-12) months (P < 0.001), whereas in

IgG Fc Receptors Provide an Alternative Infection Route for Murine Gamma-Herpesvirus-68

BACKGROUND: Herpesviruses can be neutralized in vitro but remain infectious in immune hosts. One difference between these settings is the availability of immunoglobulin Fc receptors. The question therefore arises whether a herpesvirus exposed to apparently neutralizing antibody can still infect Fc receptor(+) cells. PRINCIPAL FINDINGS: Immune sera blocked murine gamma-herpesvirus-68 (MHV-68) infection of fibroblasts, but failed to block and even enhanced its infection of macrophages and dendritic cells. Viral glycoprotein-specific monoclonal antibodies also enhanced infection. MHV-68 appeared to be predominantly latent in macrophages regardless of whether Fc receptors were engaged, but the infection was not abortive and new virus production soon overwhelmed infected cultures. Lytically infected macrophages down-regulated MHC class I-restricted antigen presentation, endocytosis and their response to LPS. CONCLUSIONS: IgG Fc receptors limit the neutralization of gamma-herpesviruses such as MHV-68

A Ribosomal Misincorporation of Lys for Arg in Human Triosephosphate Isomerase Expressed in Escherichia coli Gives Rise to Two Protein Populations

We previously observed that human homodimeric triosephosphate isomerase (HsTIM) expressed in Escherichia coli and purified to apparent homogeneity exhibits two significantly different thermal transitions. A detailed exploration of the phenomenon showed that the preparations contain two proteins; one has the expected theoretical mass, while the mass of the other is 28 Da lower. The two proteins were separated by size exclusion chromatography in 3 M urea. Both proteins correspond to HsTIM as shown by Tandem Mass Spectrometry (LC/ESI-MS/MS). The two proteins were present in nearly equimolar amounts under certain growth conditions. They were catalytically active, but differed in molecular mass, thermostability, susceptibility to urea and proteinase K. An analysis of the nucleotides in the human TIM gene revealed the presence of six codons that are not commonly used in E. coli. We examined if they were related to the formation of the two proteins. We found that expression of the enzyme in a strain that contains extra copies of genes that encode for tRNAs that frequently limit translation of heterologous proteins (Arg, Ile, Leu), as well as silent mutations of two consecutive rare Arg codons (positions 98 and 99), led to the exclusive production of the more stable protein. Further analysis by LC/ESI-MS/MS showed that the 28 Da mass difference is due to the substitution of a Lys for an Arg residue at position 99. Overall, our work shows that two proteins with different biochemical and biophysical properties that coexist in the same cell environment are translated from the same nucleotide sequence frame