A revisitation of the 1888 H.Hertz experiment

We propose a revisitation of the original experiment performed by H. Hertz in 1888. With a simple setup it is possible to produce electromagnetic waves with a frequency in the range of 3 MHz. By performing Fourier analysis of the signal captured by a resonant antenna it is possible to study the behaviour of the RLC series circuit, frequency splitting of coupled resonances and finally the characteristics of the near-field emitted by the loop antenna

Radiation induced zero-resistance states: a dressed electronic structure effect

Recent results on magnetoresistance in a two dimensional electron gas under crossed magnetic and microwave fields show a new class of oscillations, suggesting a new kind of zero-resistance states. A complete understanding of the effect is still lacking. We consider the problem from the point of view of the electronic structure dressed by photons due to a in plane linearly polarized ac field. The dramatic changes in the dressed electronic structure lead to a interpretation of the new magnetoresistance oscillations as a persistent-current like effect, induced by the radiation field.Comment: 5 pages, 5 figures, revtex4, changes in introduction and added reference

On the use of low-cost computer peripherals for the assessment of motor dysfunction in Parkinson’s disease – Quantification of bradykinesia using target tracking tasks

The potential of computer games peripherals to measure the motor dysfunction in Parkinson’s diseases is assessed. Of particular interest is the quantification of bradykinesia. Previous studies used modified or custom haptic interfaces, here an unmodified force feedback joystick and steering wheel are used with a laptop. During testing an on screen cursor moves in response to movements of the peripheral, the user has to track a continuously moving target (pursuit tracking), or move to a predetermined target (step tracking). All tasks use movement in the horizontal axis, allowing use of joystick or steering wheel. Two pursuit tracking tasks are evaluated, pseudo random movement, and a swept frequency task. Two step tracking tasks are evaluated, movement between two or between two of five fixed targets. Thirteen patients and five controls took part on a weekly basis. Patients were assessed for bradykinesia at each session using standard clinical measures. A range of quantitative measures was developed to allow comparison between and within patients and controls using ANOVA. Both peripherals are capable of discriminating between controls and patients, and between patients with different levels of bradykinesia. Recommendations for test procedures and peripherals are given

The point of departure of a particle sliding on a curved surface

A particle is thrown tangentially on a surface. It is shown that for some surfaces and for special initial velocities the thrown particle leaves immediately the surface, and for special conditions it never leaves the surface. The conditions for leaving the surface is investigated. The problem is studied for a surface with the cross section $y=f(x)$. The surfaces with the equations $f(x)= -\alpha x^{k}\ (\alpha, k>0)$ is considered in more detail. At the end the effect of friction is also considered.Comment: 10 pages, 4 figure

Phasor analysis of atom diffraction from a rotated material grating

The strength of an atom-surface interaction is determined by studying atom diffraction from a rotated material grating. A phasor diagram is developed to interpret why diffraction orders are never completely suppressed when a complex transmission function due to the van der Waals interaction is present. We also show that atom-surface interactions can produce asymmetric diffraction patterns. Our conceptual discussion is supported by experimental observations with a sodium atom beam.Comment: 5 pages, 6 figures, submitted to PR

A guide to the establishment and maintenance of pesticide laboratories in developing countries (NRI Bulletin No. 28)

The difficulties in establishing and maintaining pesticide laboratories, particularly residue laboratories, in developing countries are addressed in an attempt to arouse a greater awareness of the commitment and resources required for successful operation. Accommodation, staffing, laboratory services, equipment and materials are all considered in detail and model specifications, including full equipment lists, are provided for both formulation and residue laboratories

When Peace is Not Enough: The Flag Protests and The Politics of Identity and Belonging in East Belfast

The flag protests that occurred during the tail of 2012 and early 2013 gained international media attention. Much of the media attention focused on the involvement of young people and sought to seek answers to how young people who had grown up in more peaceful times could be involved in violence that belonged in Northern Ireland’s past. Research being conducted by the authors during the course of the flag protests on young people’s experiences of living in post conflict Belfast enabled the researchers to gain insight and clarity on the flag protests, why they had occurred and underlying factors that fuelled the riots and violence that followed, giving a snap shot of the strength of feeling and overall mood of the Protestant community at that time. Using an interpretative phenomenological analysis (IPA) approach, 2 focus groups with 14 young people aged between 15-24 (M=17 years), were conducted followed by more in-depth semi structured interviews with 6 young people from the focus groups and a further 6 interviews with youth and community workers from the East Belfast area