Power and the illusion of control: Do individual’s correctly anticipate how much influence they have within a household choice?

Choices of groups remain one of the lesser studied behaviours in the choice literature. This continues to be an oversight as many choices are made at a household or even social level. In particular, studies that seek to further our understanding of the role of individual influence in group choices remain uncommon. This paper presents the first steps of research into an even less researched area of group choice; the level of influence that individuals think they have over a group choice. In the context of motor vehicle choice among household dyads, we find that individuals mostly perceive influence to be equally shared across vehicle attributes, with the primary user of the motor vehicle, on average, perceiving themselves to be more influential than their partner. While the primary user may perceive them self to be more influential this is mismatched with what is uncovered by modelling group powers. Influence of the primary agent is limited to the type of fuel the vehicle uses. We find that perceptions of influence are predominantly a function of attitudes about vehicle emissions and the age of the individual. Overall we provide new evidence into the ability of people to assess their own influence in a negotiation process, the influence of another and the sources of discrepancy that may exist, thus adding richer insights to the contextual understanding of group decisions

Interplay of Composition, Structure, and Electron Density of States in W-Os Cathode Materials and Relationship with Thermionic Emission

The presence and composition of W-Os alloys have been found to significantly affect the thermionic emission properties of Os-coated tungsten dispenser cathodes. However, the comprehensive understanding of structure–property relationships needed to design improved tungsten cathodes with larger thermionic emission is still lacking. In this study, composition–structure–property relationships governing thermionic emission from W-Os alloys were investigated using quantum mechanical calculations. Low-energy W-Os atomic configurations at various compositions were determined from first-principles calculations based on density functional theory in combination with cluster expansion calculations. Electronic properties were investigated in terms of the electron density of states. The relative position of the Fermi level with respect to peaks and pseudogaps in the density of states for different W-Os structures can be used to explain, at least in part, observed variations in thermionic emission from Os-coated tungsten dispenser cathodes

Air safety & security: Traveller perceptions post the Malaysian Air disasters

Air transport is of substantial importance to economies, societies and freedom as it connects businesses and individuals with the world. However, two recent Malaysia Airlines incidents have resulted in even more security measures at airports and have anecdotally changed the security and safety perceptions of the traveling (or no longer traveling) public. Our study investigates for the first time attitudes towards air travel, safety and security and determines empirically if travellers are willing to experience even more invasive security measures in light of these tragedies. Our results suggest that there is a latent demand for air services despite the recent of the Malaysian Airline tragedies. Out of our proposed measures the presence of visible uniformed police creates the greatest feeling of security and it is seen as important to better communicate what security operations do and why it is effective in threat minimisation. We find willingness to pay for avoiding additional incidents both in terms of money and time but respondents are also willing to pay more to speed up the security process. Our results also suggest there is no desire to accept security processes that invade privacy considerably more what is currently practiced. We conclude that with respect to air travel the magnitude of trade-of between personal freedoms for improved security is limited. Travellers appear willing to accept risks, or perceive them as isolated and limited to airlines with inferior safety records and/or destinations with inferior security records

The relationship of high-intensity cross-training with arterial stiffness

Background Central arterial stiffness is a cardiovascular risk factor that can be readily affected through engagement in physical exercise training, with resistance and aerobic exercise having disparate affects. Despite the growing popularity of high-intensity cross-training (HICT), little is currently known about the effects of this mixed modality exercise stimulus on arterial stiffness. Therefore, the purpose of this study was to characterize the arterial stiffness of habitual HICT participants vs. aerobically active and sedentary controls using a cross-sectional design. Methods A total of 30 participants were recruited: 10 middle-aged long-term participants of HICT (CrossFit) and 20 age, sex, and height matched controls (10 recreationally active, 10 sedentary). Central and peripheral pulse wave velocities were measured for the carotid-femoral and femoral-dorsalis pedis arterial segments. Aerobic fitness (maximal oxygen uptake, VO2max) was measured and typical exercise participation rates were self-reported for each group. Results HICT participants manifested central pulse wave velocity (PWV) (5.3 ± 1.0 m/s, mean ± SD) and VO2max (43 ± 6 mL/kg/min) values nearly identical to active controls. Both active groups had significantly better values than sedentary controls (7.1 ± 1.0 m/s, p ≤ 0.001; and 32 ± 7 mL/kg/min, p = 0.01). No differences were observed in peripheral PWV between groups. Conclusion Habitual participation in HICT exercise was not associated with increased central nor peripheral arterial stiffness. Long-term HICT participants presented with similar fitness and arterial stiffness as compared with participants who practiced traditional aerobic exercise. Compared to sedentary living, HICT may offer musculoskeletal and cardiovascular health benefits without negatively impacting arterial stiffness

The impact of environmental attitudes on responses to emissions charging and vehicle choice

While there has been extensive literature on the concept of congestion there have been very few studies that explore road pricing as a function of vehicle emissions. A growing global focus on environmental concerns, in particular the role of carbon emissions in global warming, has created a social atmosphere where attitudes towards the environment are a pre-eminent focus of news media. In stated choice experiments, such attitudes play a key role in determining willingness to pay measures. This paper employs a stated preference survey to examine motor vehicle purchasing in the presence of hypothetical annual and variable emissions surcharges. Using latent class modelling, it is shown that four classes of individuals exist, whose sensitivities to annual and variable emissions surcharging differs. Importantly it is also shown that these differences can be explained by environmental attitudes. The policy implications of this result are discussed, highlighting the usefulness of the modelling technique in the management of environmental policy

Desorption from Hot Scandate Cathodes: Effects on Vacuum Device Interior Surfaces after Long-Term Operation

Scandate cathodes have exhibited superior emission properties compared to current state-of-the-art “M-type” thermionic cathodes. However, their integration into vacuum devices is limited in part by a lack of knowledge regarding their functional lifespan and behavior during operation. Here, we consider thermal desorption from scandate cathodes by examining the distribution of material deposited on interior surfaces of a sealed vacuum device after ~26,000 h of cathode operation. XPS, EDS, and TEM analyses indicate that on the order of 1 wt.% of the initial impregnate is desorbed during a cathode’s lifetime, Ca does not desorb uniformly with time, and little to no Sc desorbs from the cathode surfaces (or does so at an undetectable rate). Findings from this first-ever study of a scandate cathode after extremely long-time operation yield insight into the utility of scandate cathodes as components in vacuum devices and suggest possible effects on device performance due to deposition of desorption products on interior device surfaces

The accuracy of proxy responses in a stated choice setting

Data is typically gathered from an individual respondent who represents the group or the household. This individual is often identified as the “primary decision maker” and is often asked to provide responses as a proxy for the group as the cost of interviewing each member individually is impractical and/or expensive. The collection of joint preferences is rarely done (Arora 2006) and indeed in terms of travel behaviour research the use of proxy responses is not uncommon (Wargelin and Kostyniuk 2004, Richardson 2006). Under such a framework, there exists an assumption that the primary decision maker has perfect knowledge of other group member preferences and bargaining behaviour, and is able to synthesize this information when providing a response on their behalf. The validity of such an assumption however remains an open question, with recent research calling the reliability of proxy responses into account (Bateman and Munro 2009). In this paper, using three models estimated in willingness to pay space, we examine the accuracy of proxy responses in a stated choice experiment. We find that there is overlap between a proxy response and the own preferences of the individual providing the proxy choice, that the proxy responses fail to represent the full preference heterogeneity that exists in the actual choices made by individuals, and that when the preferences of another differ substantial from an individuals on preferences the proxy choice provided by that individual is a poor estimate. Overall we find that the ability of individuals to correctly predict the choice of other individuals in their household is poor and as a result proxy responses are unreliable estimators of preference

Near-Surface Material Phases and Microstructure of Scandate Cathodes

Scandate cathodes that were fabricated using the liquid-solid process and that exhibited excellent emission performance were characterized using complementary state-of-the-art electron microscopy techniques. Sub-micron BaAl2O4 particles were observed on the surfaces and edges of tungsten particles, as seen in cross-section samples extracted from the scandate cathode surface regions. Although several BaAl2O4 particles were observed to surround smaller Sc2O3 nanoparticles, no chemical mixing of the two oxides was detected, and in fact the distinct oxide phases were separately verified by chemical analysis and also by 3D elemental tomography. Nanobeam electron diffraction confirmed that the crystal structure throughout W grains is body-centered cubic, indicating that they are metallic W and did not experience noticeable changes, even near the grain surfaces, as a result of the numerous complex chemical reactions that occur during cathode impregnation and activation. 3D reconstruction further revealed that internal Sc/Sc2O3 particles tend to exhibit a degree of correlated arrangement within a given W particle, rather than being distributed uniformly throughout. Moreover, the formation of Sc/Sc2O3 particles within W grains may arise from W surface roughening that occurs during the liquid-solid synthesis process

Understanding light trapping by resonant coupling to guided modes and the importance of the mode profile

We present a simple conceptual model describing the absorption enhancement provided by diffraction gratings due to resonant coupling to guided modes in a multi-layered structure. In doing so, we provide insight into why certain guided modes are more strongly excited than others and demonstrate that the spatial overlap of the mode profile with the grating is important. The model is verified by comparison to optical simulations and experimental measurements. We fabricate metal nanoparticle gratings integrated as back contacts in solution-processed PbS colloidal quantum dot photodiodes. The measured photocurrent at the target wavelength is enhanced by 250%, with reference to planar devices, due to resonant coupling to guided modes with strong spatial overlap with the gratings. In comparison, resonant coupling to weakly overlapping modes results in a 25% increase at the same wavelength.Peer ReviewedPostprint (published version