Electronic stress tensor analysis of hydrogenated palladium clusters

We study the chemical bonds of small palladium clusters Pd_n (n=2-9) saturated by hydrogen atoms using electronic stress tensor. Our calculation includes bond orders which are recently proposed based on the stress tensor. It is shown that our bond orders can classify the different types of chemical bonds in those clusters. In particular, we discuss Pd-H bonds associated with the H atoms with high coordination numbers and the difference of H-H bonds in the different Pd clusters from viewpoint of the electronic stress tensor. The notion of "pseudo-spindle structure" is proposed as the region between two atoms where the largest eigenvalue of the electronic stress tensor is negative and corresponding eigenvectors forming a pattern which connects them.Comment: 22 pages, 13 figures, published online, Theoretical Chemistry Account

Cost effectiveness of recombinant factor VIIa for treatment of intracerebral hemorrhage

<p>Abstract</p> <p>Background</p> <p>Phase I/II placebo-controlled clinical trials of recombinant Factor VIIa (rFVIIa) suggested that administration of rFVIIa within 4 hours after onset of intracerebral hemorrhage (ICH) is safe, limits ICH growth, and improves outcomes. We sought to determine the cost-effectiveness of rFVIIa for acute ICH treatment, using published Phase II data. We hypothesized that rFVIIa would have a low marginal cost-effectiveness ratio (mCER) given the poor neurologic outcomes after ICH with conventional management.</p> <p>Methods</p> <p>We performed an incremental cost-effectiveness analysis from the societal perspective, considering conventional management vs. 80 ug/kg rFVIIa treatment for acute ICH cases meeting Phase II inclusion criteria. The time frame for the analysis was 1. 25 years: data from the Phase II trial was used for 90 day outcomes and rFVIIa complications – arterial thromboembolic events (ATE). We assumed no substantial cost differences in care between the two strategies except: 1) cost of rFVIIa (for an 80 mcg/kg dose in an 80 kg patient, assumed cost of $6,408); 2) cost of ATE side effects from rFVIIa (which also decrease quality of life and increase the chance of death); and 3) differential monetary costs of outcomes and their impact on quality of life, including disposition (home vs. nursing home), and outpatient vs. inpatient rehabilitation. Sensitivity analyses were performed to explore uncertainty in parameter estimates, impact of rFVIIa cost, direct cost of neurologic outcomes, probability of ATE, and outcomes after ATE.</p> <p>Results</p> <p>In the "base case", treating ICH with rFVIIa dominates the usual care strategy by being more effective and less costly. rFVIIa maintained a mCER <$50,000/QALY over a wide range of sensitivity analyses. Sensitivity analyses showed that the cost of rFVIIa must exceed $14,500, or the frequency of ATE exceed 29$50,000/QALY. Varying the cost and/or reducing the utility of health states following ATE did not impact results.</p> <p>Conclusion</p> <p>Based on data from preliminary trials, treating selected ICH patients with rFVIIa results in lower cost and improved clinical outcomes. This potential cost-effectiveness must be considered in light of the Phase III trial results.</p

A Close Nuclear Black Hole Pair in the Spiral Galaxy NGC 3393

The current picture of galaxy evolution advocates co-evolution of galaxies and their nuclear massive black holes (MBHs), through accretion and merging. Quasar pairs (6,000-300,000 light-years separation) exemplify the first stages of this gravitational interaction. The final stages, through binary MBHs and final collapse with gravitational wave emission, are consistent with the sub-light-year separation MBHs inferred from optical spectra and light-variability of two quasars. The double active nuclei of few nearby galaxies with disrupted morphology and intense star formation (e.g., NGC 6240 and Mkn 463; ~2,400 and ~12,000 light-years separation respectively) demonstrate the importance of major mergers of equal mass spirals in this evolution, leading to an elliptical galaxy, as in the case of the double radio nucleus (~15 light-years separation) elliptical 0402+379. Minor mergers of galaxies with a smaller companion should be a more common occurrence, evolving into spiral galaxies with active MBH pairs, but have hitherto not been seen. Here we report the presence of two active MBHs, separated by ~430 light-years, in the Seyfert galaxy NGC 3393. The regular spiral morphology and predominantly old circum-nuclear stellar population of this galaxy, and the closeness of the MBHs embedded in the bulge, suggest the result of minor merger evolution.Comment: Preprint (not final) version of a paper to appear in Natur

The effect of S-substitution at the O6-guanine site on the structure and dynamics of a DNA oligomer containing a G:T mismatch

The effect of S-substitution on the O6 guanine site of a 13-mer DNA duplex containing a G:T mismatch is studied using molecular dynamics. The structure, dynamic evolution and hydration of the S-substituted duplex are compared with those of a normal duplex, a duplex with Ssubstitution on guanine, but no mismatch and a duplex with just a G:T mismatch. The S-substituted mismatch leads to cell death rather than repair. One suggestion is that the G:T mismatch recognition protein recognises the S-substituted mismatch (GS:T) as G:T. This leads to a cycle of futile repair ending in DNA breakage and cell death. We find that some structural features of the helix are similar for the duplex with the G:T mismatch and that with the S-substituted mismatch, but differ from the normal duplex, notably the helical twist. These differences arise from the change in the hydrogen-bonding pattern of the base pair. However a marked feature of the S-substituted G:T mismatch duplex is a very large opening. This showed considerable variability. It is suggested that this enlarged opening would lend support to an alternative model of cell death in which the mismatch protein attaches to thioguanine and activates downstream damage-response pathways. Attack on the sulphur by reactive oxygen species, also leading to cell death, would also be aided by the large, variable opening

How managers can build trust in strategic alliances: a meta-analysis on the central trust-building mechanisms

Trust is an important driver of superior alliance performance. Alliance managers are influential in this regard because trust requires active involvement, commitment and the dedicated support of the key actors involved in the strategic alliance. Despite the importance of trust for explaining alliance performance, little effort has been made to systematically investigate the mechanisms that managers can use to purposefully create trust in strategic alliances. We use Parkhe’s (1998b) theoretical framework to derive nine hypotheses that distinguish between process-based, characteristic-based and institutional-based trust-building mechanisms. Our meta-analysis of 64 empirical studies shows that trust is strongly related to alliance performance. Process-based mechanisms are more important for building trust than characteristic- and institutional-based mechanisms. The effects of prior ties and asset specificity are not as strong as expected and the impact of safeguards on trust is not well understood. Overall, theoretical trust research has outpaced empirical research by far and promising opportunities for future empirical research exist

Motion estimation and correction for simultaneous PET/MR using SIRF and CIL

SIRF is a powerful PET/MR image reconstruction research tool for processing data and developing new algorithms. In this research, new developments to SIRF are presented, with focus on motion estimation and correction. SIRF's recent inclusion of the adjoint of the resampling operator allows gradient propagation through resampling, enabling the MCIR technique. Another enhancement enabled registering and resampling of complex images, suitable for MRI. Furthermore, SIRF's integration with the optimization library CIL enables the use of novel algorithms. Finally, SPM is now supported, in addition to NiftyReg, for registration. Results of MR and PET MCIR reconstructions are presented, using FISTA and PDHG, respectively. These demonstrate the advantages of incorporating motion correction and variational and structural priors. This article is part of the theme issue 'Synergistic tomographic image reconstruction: part 2'

Expressing one’s feelings and listening to others increases emotional intelligence: a pilot study of Asian medical students

&lt;p&gt;Background: There has been considerable interest in Emotional Intelligence (EI) in undergraduate medical education, with respect to student selection and admissions, health and well-being and academic performance. EI is a significant component of the physician-patient relationship. The emotional well-being of the physician is, therefore, a significant component in patient care. The aim is to examine the measurement of TEIQue-SF in Asian medical students and to explore how the practice of listening to the feelings of others and expressing one’s own feelings influences an individual’s EI, set in the context of the emotional well-being of a medical practitioner.&lt;/p&gt; &lt;p&gt;Methods: A group of 183 international undergraduate medical students attended a half-day workshop (WS) about mental-health and well-being. They completed a self-reported measure of EI on three occasions, pre- and post-workshop, and a 1-year follow-up.&lt;/p&gt; &lt;p&gt;Result: The reliability of TEIQue-SF was high and the reliabilities of its four factors were acceptable. There were strong correlations between the TEIQue-SF and personality traits. A paired t-test indicated significant positive changes after the WS for all students (n=181, p= .014), male students (n=78, p= .015) and non-Japanese students (n=112, p= .007), but a repeated measures analysis showed that one year post-workshop there were significant positive changes for all students (n=55, p= .034), female students (n=31, p= .007), especially Japanese female students (n=13, p= .023). Moreover, 80% of the students reported that they were more attentive listeners, and 60% agreed that they were more confident in dealing with emotional issues, both within themselves and in others, as a result of the workshop.&lt;/p&gt; &lt;p&gt;Conclusion: This study found the measurement of TEIQue-SF is appropriate and reliable to use for Asian medical students. The mental health workshop was helpful to develop medical students’ EI but showed different results for gender and nationality. The immediate impact on the emotional awareness of individuals was particularly significant for male students and the non-Japanese group. The impact over the long term was notable for the significant increase in EI for females and Japanese. Japanese female students were more conscious about emotionality. Emotion-driven communication exercises might strongly influence the development of students’ EI over a year.&lt;/p&gt

A Study of Problem Solving Using Blocks Vehicle in a STEAM Course for Lower Elementary Levels

STEAM education is currently one of the most important parts of the elementary school curriculum. If STEAM learning can cultivate good problem-solving ability, it will also help improve judgment and thinking abilities. Several voices in the literature have argued for cooperative learning in STEAM courses. Although the effectiveness of course learning often is evaluated using course feedback forms, there is comparatively little emphasis on whether a course succeeds in realizing cooperative learning. For a course involving self-propelled toy-brick cars, there is little research on the application of low-grade pupils. Therefore, based on the integration of STEAM courses into self-propelled toy-brick car learning, this study applied two learning strategies of cooperative learning and individual learning to low-grade pupils in the second grade in elementary schools. After completing the course problem-solving ability indicators were measured and analyzed using the problem-solving ability test. The results show that the mean score of the experimental group in the problem-solving ability test was higher than that of the control group. In the problem-solving ability test, the scores of the two groups were also significantly different, which suggests that cooperative learning is more effective than individual learning strategies.acceptedVersio

Grid-texture mechanisms in human vision:contrast detection of regular sparse micro-patterns requires specialist templates

Previous work has shown that human vision performs spatial integration of luminance contrast energy, where signals are squared and summed (with internal noise) over area at detection threshold. We tested that model here in an experiment using arrays of micro-pattern textures that varied in overall stimulus area and sparseness of their target elements, where the contrast of each element was normalised for sensitivity across the visual field. We found a power-law improvement in performance with stimulus area, and a decrease in sensitivity with sparseness. While the contrast integrator model performed well when target elements constituted 50–100% of the target area (replicating previous results), observers outperformed the model when texture elements were sparser than this. This result required the inclusion of further templates in our model, selective for grids of various regular texture densities. By assuming a MAX operation across these noisy mechanisms the model also accounted for the increase in the slope of the psychometric function that occurred as texture density decreased. Thus, for the first time, mechanisms that are selective for texture density have been revealed at contrast detection threshold. We suggest that these mechanisms have a role to play in the perception of visual textures