Heterogeneity assumptions in the specification of bargaining models: a study of household level trade-offs between commuting time and salary

With many real world decisions being made in conjunction with other decision makers, or single agent decisions having an influence on other members of the decision maker's immediate entourage, there is strong interest in studying the relative weight assigned to different agents in such contexts. In the present paper, we focus on the case of one member of a two person household being asked to make choices affecting the travel time and salary of both members. We highlight the presence of significant heterogeneity across individuals not just in their underlying sensitivities, but also in the relative weight they assign to their partner, and show how this weight varies across attributes. This is in contrast to existing work which uses weights assigned to individual agents at the level of the overall utility rather than for individual attributes. We also show clear evidence of a risk of confounding between heterogeneity in marginal sensitivities and heterogeneity in the weights assigned to each member. We show how this can lead to misleading model results, and argue that this may also explain past results showing bargaining or weight parameters outside the usual [0,1] range in more traditional joint decision making contexts. In terms of substantive results, we find that male respondents place more weight on their partner's travel time, while female respondents place more weight on their partner's salary.

Quantum state storage and processing for polarization qubits in an inhomogeneously broadened Λ-type three-level medium

We address the propagation of a single photon pulse with two polarization components, i.e., a polarization qubit, in an inhomogeneously broadened "phaseonium" \Lambda-type three-level medium. We combine some of the non-trivial propagation effects characteristic for this kind of coherently prepared systems and the controlled reversible inhomogeneous broadening technique to propose several quantum information processing applications, such as a protocol for polarization qubit filtering and sieving as well as a tunable polarization beam splitter. Moreover, we show that, by imposing a spatial variation of the atomic coherence phase, an effcient quantum memory for the incident polarization qubit can be also implemented in \Lambda-type three-level systems.

A-level Mathematics Module Choice and Subsequent Performance in First Year of an Engineering Degree

The A-level Mathematics qualification is based on a compulsory set of pure maths modules and a selection of applied maths modules. The flexibility in choice of applied modules has led to concerns that many students would proceed to study engineering at university with little background in mechanics. A survey of aerospace and mechanical engineering students in our university revealed that a combination of mechanics and statistics (the basic module in both) was by far the most popular choice of optional modules in A-level Mathematics, meaning that only about one-quarter of the class had studied mechanics beyond the basic module within school mathematics. Investigation of student performance in two core, first-year engineering courses, which build on a mechanics foundation, indicated that any benefits for students who studied the extra mechanics at school were small. These results give concern about the depth of understanding in mechanics gained during A-level Mathematics.

Getting In and Getting On? The Experiences of Young People with Visual Impairments and Hearing Impairments in Third-Level Education

Young disabled people continue to be under-represented throughout further and higher education settings. Drawing on Pierre Bourdieu’s social theory of habitus, capital and field, this paper explores the practices of domination and oppression that have made it difficult for young people with visual impairments and hearing impairments to participate in third-level education on the same basis as non-disabled people. Twenty young people with hearing impairments and visual impairments were interviewed about their educational experiences. In addition, 31 interviews were conducted with third-level education providers, policy-makers and non-governmental organisations. This article has two aims: firstly, to critically examine the experiences of young people with hearing impairments and visual impairments in accessing and engaging with support provisions in further and higher education settings; and secondly, to identify and explore the diversity of ways in which these young people have managed and responded to the practices they have encountered. This article emphasises the journey from ability to dis-ability that young people with hearing and visual impairments experience in their quest for educational achievement. The ambiguities of “inclusion”, “widening participation” and “support” are highlighted and critiqued for their extensive failure to challenge taken-for-granted discourses.

Probing spin-orbit-interaction-induced electron dynamics in the carbon atom by multiphoton ionization

We use R-matrix theory with time dependence (RMT) to investigate multiphoton ionization of ground-state atomic carbon with initial orbital magnetic quantum number M_L=0 and M_L=1 at a laser wavelength of 390 nm and peak intensity of 10(14) W/cm(2). Significant differences in ionization yield and ejected-electron momentum distribution are observed between the two values for M_L. We use our theoretical results to model how the spin-orbit interaction affects electron emission along the laser polarization axis. Under the assumption that an initial C atom is prepared at zero time delay with M_L=0, the dynamics with respect to time delay of an ionizing probe pulse modeled by using RMT theory is found to be in good agreement with available experimental data.

Systolic two-port adaptor for high performance wave digital filtering

The authors present a VLSI circuit for implementing wave digital filter (WDF) two-port adaptors. Considerable speedups over conventional designs have been obtained using fine grained pipelining. This has been achieved through the use of most significant bit (MSB) first carry-save arithmetic, which allows systems to be designed in which latency L is small and independent of either coefficient or input data wordlength. L is determined by the online delay associated with the computation required at each node in the circuit (in this case a multiply/add plus two separate additions). This in turn means that pipelining can be used to considerably enhance the sampling rate of a recursive digital filter. The level of pipelining which will offer enhancement is determined by L and is fine-grained rather than bit level. In the case of the circuit considered, L = 3. For this reason pipeline delays (half latches) have been introduced between every two rows of cells to produce a system with a once every cycle sample rate.

Positronium-atom scattering at low energies

A pseudopotential for positronium-atom interaction, based on electron-atom and positron-atom phase shifts, is constructed, and the phase shifts for Ps-Kr and Ps-Ar scattering are calculated. This approach allows us to extend the Ps-atom cross sections, obtained previously in the impulse approximation [I. I. Fabrikant and G. F. Gribakin, Phys. Rev. Lett. 112, 243201 (2014)], to energies below the Ps ionization threshold. Although experimental data are not available in this low-energy region, our results describe well the tendency of the measured cross sections to drop with decreasing velocity at v < 1 a.u. Our results show that the effect of the Ps-atom van der Waals interaction is weak compared to the polarization interaction in electron-atom and positron-atom scattering. As a result, the Ps scattering length for both Ar and Kr is positive, and the Ramsauer-Townsend minimum is not observed for Ps scattering from these targets. This makes Ps scattering quite different from electron scattering in the low-energy region, in contrast to the intermediate energy range from the Ps ionization threshold up to v ∼ 2 a.u., where the two are similar.

The reaction path of CO and Fe2O3 in a chemical-looping combustion system

The reaction mechanism of CO and Fe₂O₃ in a chemical-looping combustion (CLC) was studied based on density functional theory (DFT) at B3LYP level in this paper. The structures of all reactants, intermediate, transition structures and products of this reaction had been optimized and characterized. The reaction path was validated by means of the intrinsic reaction coordinate (IRC) approach. The result showed that the reaction was divided into two steps, the adsorbed CO molecule on Fe ₂O₃ surface formed a medium state with one broken Fe-O bond in step1, and in step2, O atom broken here oxidized a subsequent CO molecule in the fuel reactor. Thus, Fe₂O₃ molecule transport O from air to oxide CO continually in the CLC process. The activation energy and rate coefficients of the two steps were also obtained.

Two potential clinical applications of the alkaline single-cell gel electrophoresis assay .1. Human bladder washings and transitional cell carcinoma of the bladder .2. Human sperm and male infertility

Part 1: The alkaline single-cell gel electrophoresis (comet) assay was used to analyse the integrity and DNA content of exfoliated cells extracted from bladder washing specimens from 9 transitional cell carcinoma patients and 15 control patients. DNA damage, as expressed by % tail DNA and tail moment values, was observed to occur in cells from both control and bladder cancer samples. The extent of the damage was, however, found to be significantly greater in the cancer group than in the control group. Comet optical density values were also recorded for each cell analysed in the comet assay and although differences observed between tumour grades were not found to be statistically significant, the mean comet optical density value was observed to be greater in the cancer group than in the control population studied, These preliminary results suggest that the comet assay may have potential as a diagnostic tool and as a prognostic indicator in transitional cell carcinoma, Part 2: Baseline DNA damage in sperm cells from 13 normozoospermic fertile males, 17 normozoospermic infertile males and 11 asthenozoospermic infertile males were compared using a modified alkaline comet assay technique. No significant difference in the level of baseline DNA damage was observed between the 3 categories of sperm studied; however the untreated sperm cells were observed to display approximately 20% tail DNA. This is notably higher than the background DNA damage observed in somatic cells where the % tail DNA is normally less than 5%. Sperm from the 3 groups of men studied were also compared for sensitivity to DNA breakage, using the modified alkaline comet assay, following X-ray irradiations (5, 10 and 30 Gy) and hydrogen peroxide treatments (40, 100 and 200 mu M). Significant levels of X-ray-induced damage were found relative to untreated control sperm in the two infertile groups following 30 Gy irradiation. Significant damage in hydrogen peroxide-treated sperm was observed in sperm from fertile samples, at 200 mu M and in infertile samples at 100- and 200-mu M doses relative to controls. These results therefore indicate that fertile sperm samples are more resistant to X-ray- and hydrogen peroxide-induced DNA breakage than infertile samples. Further studies involving greater numbers of individuals are currently in progress to confirm these findings.

Sea-level changes in Iceland and the influence of the North Atlantic Oscillation during the last half millennium

We present a new, diatom-based sea-level reconstruction for Iceland spanning the last -500 years, and investigate the possible mechanisms driving the sea-level changes. A sea-level reconstruction from near the Icelandic low pressure system is important as it can improve understanding of ocean-atmosphere forcing on North Atlantic sea-level variability over multi-decadal to centennial timescales. Our reconstruction is from Viarhólmi salt marsh in Snæfellsnes in western Iceland, a site from where we previously obtained a 2000-yr record based upon less precise sea-level indicators (salt-marsh foraminifera). The 20th century part of our record is corroborated by tide-gauge data from Reykjavik. Overall, the new reconstruction shows ca0.6m rise of relative sea level during the last four centuries, of which ca0.2m occurred during the 20th century. Low-amplitude and high-frequency sea-level variability is super-imposed on the pre-industrial long-term rising trend of 0.65m per 1000 years. Most of the relative sea-level rise occurred in three distinct periods: AD 1620-1650, AD 1780-1850 and AD 1950-2000, with maximum rates of ~3±2mm/yr during the latter two of these periods. Maximum rates were achieved at the end of large shifts (from negative to positive) of the winter North Atlantic Oscillation (NAO) Index as reconstructed from proxy data. Instrumental data demonstrate that a strong and sustained positive NAO (a deep Icelandic Low) generates setup on the west coast of Iceland resulting in rising sea levels. There is no strong evidence that the periods of rapid sea-level rise were caused by ocean mass changes, glacial isostatic adjustment or regional steric change. We suggest that wind forcing plays an important role in causing regional-scale coastal sea-level variability in the North Atlantic, not only on (multi-)annual timescales, but also on multi-decadal to centennial timescales.

In Defiance of Duverger: The Class Cleavage and the Emergence of District-Level Multiparty Systems in Western Europe

At its core, Duverger’s Law—holding that the number of viable parties in first-past-the-post systems should not exceed two—applies primarily at the district level. While the number of parties nationally may exceed two, district-level party system fragmentation should not. Given that a growing body of research shows that district-level party system fragmentation can indeed exceed two in first-past-the-post systems, I explore whether the major alternative explanation for party system fragmentation—the social cleavage approach—can explain such violations of Duverger’s Law. Testing this argument in several West European elections prior to the adoption of proportional representation, I find evidence favouring a social cleavage explanation: with the expansion of the class cleavage, the average district-level party system eventually came to violate the two-party predictions associated with Duverger’s Law. This suggests that sufficient social cleavage diversity may produce multiparty systems in other first-past-the-post systems.

The effect of level of straw bale provision on the behaviour and leg health of commercial broiler chickens

This study aimed to assess the effect of the number of straw bales (SBs) provided on the behaviour and leg health of commercial broiler chickens. Houses containing ~23 000 broiler chickens were assigned to one of two treatments: (1) access to 30 SBs per house, ‘30SB’ or (2) access to 45 SB per house, ‘45SB’. This equated to bale densities of 1 bale/44 m2 and 1 bale/29 m2 of floor space within houses, respectively. Treatments were applied in one of two houses on a commercial farm, and were replicated over six production cycles. Both houses had windows and were also artificially lit. Behaviour was observed in weeks 3 to5 of the cycle. This involved observations of general behaviour and activity, gait scores (0: perfect to 5: unable to walk) and latency to lie (measured in seconds from when a bird had been encouraged to stand). Production performance and environmental parameters were also measured. SB density had no significant effect on activity levels (P>0.05) or walking ability (P>0.05). However, the average latency to lie was greater in 30SB birds compared with 45SB birds (P<0.05). The incidence of hock burn and podo dermatitis, average BW at slaughter and levels of mortality and culling were unaffected by SB density (P>0.05). The results from this study suggest that increasing SB levels from 1 bale/44 m2 to 1 bale/29 m2 floor space does not lead to significant improvements in the welfare of commercial broiler chickens in windowed houses.

Family Economic Vulnerability & the Great Recession: An Analysis of the First two Waves of the Growing Up in Ireland Study

In this paper we make use of the first and second waves of the 2008 and 1998 cohorts of the Growing Up in Ireland study, to develop a multidimensional and dynamic approach to understanding the impact on families and children in Ireland of the Great Recession. Economic vulnerability is operationalised as involving a distinctive risk profile in relation to relative income, household joblessness and economic stress. We find that the recession was associated with a significant increase in levels of economic vulnerability and changing risk profiles involving a more prominent role for economic stress for both the 2008 and 1998 cohorts. The factors affecting vulnerability outcomes were broadly similar for both cohorts. Persistent economic vulnerability was significantly associated with lone parenthood, particularly for those with more than one child, lower levels of Primary Care Giver (PCG) education and to a lesser extent younger age of PCG at child’s birth, number of children and a parent leaving or dying. Similar factors were associated with transient vulnerability in the first wave but the magnitude of the effects was significantly weaker particularly in relation to lone parenthood and level of education of the PCG. For entry into vulnerability the impact of these factors was again substantially weaker than for persistent and transient vulnerability indicating a significantly greater degree of socio-economic heterogeneity among the group that became vulnerable during the recession. The findings raise policy and political problems that go beyond those associated with catering for groups that have tended to be characterized by high dependence on social welfare.

A-level Mathematics Options – Views of Secondary-level Teachers

The A-level Mathematics qualification is based on a compulsory set of pure maths modules and a selection of applied maths modules with the pure maths representing two thirds of the assessment. The applied maths section includes mechanics, statistics and (sometimes) decision maths. A combination of mechanics and statistics tends to be the most popular choice by far. The current study aims to understand how maths teachers in secondary education make decisions regarding the curriculum options and offers useful insight to those currently designing the new A-level specifications.

Semi-structured interviews were conducted with A-level maths teachers representing 27 grammar schools across Northern Ireland. Teachers were generally in agreement regarding the importance of pure maths and the balance between pure and applied within the A-level maths curriculum. A wide variety of opinions existed concerning the applied options. While many believe that the basic mechanics-statistics (M1-S1) combination is most accessible, it was also noted that the M1-M2 combination fits neatly alongside A-level physics. Lack of resources, timetabling constraints and competition with other subjects in the curriculum hinder uptake of A-level Further Maths.

Teachers are very conscious of the need to obtain high grades to benefit both their pupils and the school’s reputation. The move to a linear assessment system in England while Northern Ireland retains the modular system is likely to cause some schools to review their choice of exam board although there is disagreement as to whether a modular or linear system is more advantageous for pupils. The upcoming change in the specification offers an opportunity to refresh the assessment also and reduce the number of leading questions. However, teachers note that there are serious issues with GCSE maths and these have implications for A-level.

Catalyst Deactivation on a Two-Stroke Engine

With the legislative demands increasing on recreational vehicles and utility engined applications, the two-stroke engine is facing increasing pressure to meet these requirements. One method of achieving the required reduction is via the introduction of a catalytic converter. The catalytic converter not only has to deal with the characteristically higher CO and HC concentration, but also any oil which is added to lubricate the engine. In a conventional two-stroke engine with a total loss lubrication system, the oil is either scavenged straight out the exhaust port or is entrained, involved in combustion and is later exhausted. This oil can have a significant effect on the performance of the catalyst.
To investigate the oiling effect, three catalytic converters were aged using a 400cm₃ DI two-stroke engine. A finite level of oil was added to the inlet air of the engine to lubricate the internal workings. The oil flow rate is independent of the engine speed and load.

Three catalysts were aged for 50 hours, experiencing a constant space velocity and set engine conditions. The engine was fueled on petrol and later on propane to eliminate the effects, if any, of petrol additives on catalyst deactivation. The oiling rate was varied to investigated deactivation from oil contamination. Post-mortem analysis was performed on the three catalysts. This consisted of a controlled light-off test performed on a catalyst rig, during which period, temperatures were measured and recorded towere aged for 50 hours, experiencing a constant space velocity and set engine conditions. The engine was fueled on petrol and later on propane to eliminate the effects, if any, of petrol additives on catalyst deactivation. The oiling rate was varied to investigated deactivation from oil contamination. Post-mortem analysis was performed on the three catalysts. This consisted of a controlled light-off test performed on a catalyst rig, during which period, temperatures were measured and recorded to find out where deactivation of each catalyst was occurring. The recorded results were all analyzed and these showed that from the measured light-off temperatures the aged catalysts behaved similarly. However the pattern in the light-off was significantly different when the engine was fueled by propane as opposed to gasoline.