Quantitative analysis in a heuristic evaluation experiment

In usability context of interactive systems the heuristic evaluation method is widespread. In most applications the results tend to be qualitative, describing such aspects that require some improvement for the benefit of usability. However, these qualitative results do not allow us to determine how usable it is or how it becomes an interactive system. Hence the need for quantitative results may also be very necessary in order to determine the effort that would be needed to get a sufficiently usable system.This article describes, following the idea of the UsabAIPO Project, a new experiment to obtain quantitative results after a heuristic evaluation. This new experimentation has required some variation on the original idea, working with a set of different heuristic categories, while considering the use of the score depending on severity and frequency parameters.     

The effect of price promotions on consumer shopping behavior across online and offline channels: differences between frequent and non-frequent shoppers

Information Systems and e-Business Management - This study evaluates the differential effect of price promotions on brand choice across the offline and online channels of a grocery retailer. We use...     

Effects and interactions of temperature and stress-level related damage on permeability of concrete

The objective of this study is to investigate damage-temperature-stress level-permeability interactions in structural concrete. The tests are performed on hollow cylindrical concrete specimens, subjected to compressive loading and temperature up to 150 °C. The results emphasize that at stress levels lower than 80% of the peak stress, the variation of permeability is small and it is slightly influenced by the stress. As a matter of fact, the permeability under load is smaller than the permeability measured after unloading. As the load exceeds 80% of the peak stress, micro-cracking increases rapidly, causing an increase of the permeability and a greater sensitivity to the applied load, i.e. a noticeable difference between the permeability measured under load and after unloading, the first becoming greater than the latter. In the post-peak phase the increase of permeability is much larger due to significant crack width growth. The increase of permeability with the applied load seems to be greater with temperature, inducing further alterations of concrete and dilation of the porous structure of the material. Finally, the experimental results seem to agree with the format of coupled evolution of the permeability due to damage and temperature assumed by Gawin et al. [D. Gawin, C.E. Majorana, B.A. Schrefler, Numerical analysis of hygro-thermal behaviour and damage of concrete at high temperature, Mechanics of Cohesive-Frictional Materials 4 (1999) 37-74.].     

Porous methacrylate tissue engineering scaffolds: using carbon dioxide to control porosity and interconnectivity

Porous scaffold structures are used in tissue engineering to provide structural guidance for regenerating tissues. The use of carbon dioxide (CO₂) to create such scaffolds has received some attention in the past but many researchers believe that although CO₂ processing of polymers can lead to porous scaffolds there is limited interconnectivity between the pores. In this study, highly porous (greater than 85%) and well interconnected scaffolds were obtained in which the size, distribution and number of pores could be controlled. This control was achieved by altering the rate of venting from polymer discs saturated with CO₂ under modest temperature and pressure. The polymer used is a blend of poly (ethyl methacrylate) and tetrahydrofurfuryl methacrylate (PEMA/THFMA). This polymer system has shown promise for potential applications in cartilage repair.     

High Performance Air Pollution Simulation Using OpenMP

The aim of this work is to provide a high performance air quality simulation using the sulphur transport Eulerian model 2 (STEM-II) program. First of all we optimize the sequential program with the aim of increasing data locality. Then, the optimized program is parallelized using OpenMP shared-memory directives. Experimental results on a 32-processor SGI Origin 2000 show that the parallel program achieves important reductions in the execution times.     

Inverse Analysis of Impact Test Data: Experimental Study on Polymeric Materials Displaying Brittle Behaviour

This paper deals with the influence of the testing equipment on impact load measurements. A previously developed method of analysis and processing of the experimental data based on a refined analogical model of the impact event and inverse problem techniques is used. This method makes it possible to obtain the mechanical response of the material, notwithstanding the disturbance of the dynamic effects associated to the test. Results from tests carried out both on falling weight and swing pendulum instrumented testing machines are compared. It is shown that this method can give an accurate estimation of the actual bending force in impact testing independent of the testing equipment.     

Running from Stress: Neurobiological Mechanisms of Exercise-Induced Stress Resilience

Chronic stress, even stress of a moderate intensity related to daily life, is widely acknowledged to be a predisposing or precipitating factor in neuropsychiatric diseases. There is a clear relationship between disturbances induced by stressful stimuli, especially long-lasting stimuli, and cognitive deficits in rodent models of affective disorders. Regular physical activity has a positive effect on the central nervous system (CNS) functions, contributes to an improvement in mood and of cognitive abilities (including memory and learning), and is correlated with an increase in the expression of the neurotrophic factors and markers of synaptic plasticity as well as a reduction in the inflammatory factors. Studies published so far show that the energy challenge caused by physical exercise can affect the CNS by improving cellular bioenergetics, stimulating the processes responsible for the removal of damaged organelles and molecules, and attenuating inflammation processes. Regular physical activity brings another important benefit: increased stress robustness. The evidence from animal studies is that a sedentary lifestyle is associated with stress vulnerability, whereas a physically active lifestyle is associated with stress resilience. Here, we have performed a comprehensive PubMed Search Strategy for accomplishing an exhaustive literature review. In this review, we discuss the findings from experimental studies on the molecular and neurobiological mechanisms underlying the impact of exercise on brain resilience. A thorough understanding of the mechanisms underlying the neuroprotective potential of preconditioning exercise and of the role of exercise in stress resilience, among other things, may open further options for prevention and therapy in the treatment of CNS diseases.     

Effect of the Interaction between Elevated Carbon Dioxide and Iron Limitation on Proteomic Profiling of Soybean

Elevated atmospheric CO₂ (eCO₂) and iron (Fe) availability are important factors affecting plant growth that may impact the proteomic profile of crop plants. In this study, soybean plants treated under Fe-limited (0.5 mM) and Fe-sufficient (20 mM) conditions were grown at ambient (400 μmol mol⁻¹) and eCO₂ (800 μmol mol⁻¹) in hydroponic solutions. Elevated CO₂ increased biomass from 2.14 to 3.14 g plant⁻¹ and from 1.18 to 2.91 g plant⁻¹ under Fe-sufficient and Fe-limited conditions, respectively, but did not affect leaf photosynthesis. Sugar concentration increased from 10.92 to 26.17 μmol g FW⁻¹ in roots of Fe-sufficient plants and from 8.75 to 19.89 μmol g FW⁻¹ of Fe-limited plants after exposure to eCO₂. In leaves, sugar concentration increased from 33.62 to 52.22 μmol g FW⁻¹ and from 34.80 to 46.70 μmol g FW⁻¹ in Fe-sufficient and Fe-limited conditions, respectively, under eCO₂. However, Fe-limitation decreases photosynthesis and biomass. Pathway enrichment analysis showed that cell wall organization, glutathione metabolism, photosynthesis, stress-related proteins, and biosynthesis of secondary compounds changed in root tissues to cope with Fe-stress. Moreover, under eCO₂, at sufficient or limited Fe supply, it was shown an increase in the abundance of proteins involved in glycolysis, starch and sucrose metabolism, biosynthesis of plant hormones gibberellins, and decreased levels of protein biosynthesis. Our results revealed that proteins and metabolic pathways related to Fe-limitation changed the effects of eCO₂ and negatively impacted soybean production.     

Unpredicted Aberrant Splicing Products Identified in Postmortem Sudden Cardiac Death Samples

Molecular screening for pathogenic mutations in sudden cardiac death (SCD)-related genes is common practice for SCD cases. However, test results may lead to uncertainty because of the identification of variants of unknown significance (VUS) occurring in up to 70% of total identified variants due to a lack of experimental studies. Genetic variants affecting potential splice site variants are among the most difficult to interpret. The aim of this study was to examine rare intronic variants identified in the exonic flanking sequence to meet two main objectives: first, to validate that canonical intronic variants produce aberrant splicing; second, to determine whether rare intronic variants predicted as VUS may affect the splicing product. To achieve these objectives, 28 heart samples of cases of SCD carrying rare intronic variants were studied. Samples were analyzed using 85 SCD genes in custom panel sequencing. Our results showed that rare intronic variants affecting the most canonical splice sites displayed in 100% of cases that they would affect the splicing product, possibly causing aberrant isoforms. However, 25% of these cases (1/4) showed normal splicing, contradicting the in silico results. On the contrary, in silico results predicted an effect in 0% of cases, and experimental results showed >20% (3/14) unpredicted aberrant splicing. Thus, deep intron variants are likely predicted to not have an effect, which, based on our results, might be an underestimation of their effect and, therefore, of their pathogenicity classification and family members’ follow-up.     

Effects of Substance P and Neurokinin A on the Contractile Activity of Inflamed Porcine Uterus

Disturbances in uterine contractile activity contribute to the development of inflammation, and recent evidence indicates that tachykinins, including substance P (SP) and neurokinin A (NKA), are involved in controlling uterine function. Here, we determined the effect of Escherichia coli (E. coli)-induced inflammation on expression of protein receptor subtypes for substance P (NK1R) and neurokinin A (NK2R) in the pig myometrium as well as their role in contractility of inflamed uterus. The severe acute endometritis developed in the E. coli group and the expression of NK1R and NK2R proteins increased in the myometrium. Compared to the pre-administration period, SP (10⁻⁶ M) reduced the amplitude and frequency in the myometrium of the E. coli group and the amplitude was higher and the frequency was lower versus other groups. NKA reduced the amplitude and increased the frequency in endometrium/myometrium of the E. coli group. In this group, the amplitude was lower and the frequency was higher than in the CON and SAL groups. Our research showed that NK2R (10⁻⁶ M) antagonist application abolished the NKA inhibitory effect on uterine amplitude. The application of the NK1R (10⁻⁵ M) antagonist together with SP revealed that the inhibitory effect of SP on uterine contractility is achieved independently of the NKR1. Additionally, taking into account the fact that NKA shows an inhibitory effect with the use of NK2R on uterine amplitude suggests the possibility of therapeutic use of the antagonist as a drug increasing uterine contractility in inflammation.