The diocotron instability in a quasi-toroidal geometry

Slipstream instability of low density electron beams in crossed electric and magnetic field

Transition into adult healthcare services in Scotland –findings from a study concerning service users at the Scottish Spina Bifida Association

Background and Aims: Literature on interventions that enable young people with spina bifida and/or hydrocephalus to have smooth transition, into adult healthcare services, stress the need for the process to start early and to include all family members. The study reported here was set to quantify and articulate the experiences of service users who are or due to be going through the transition process in Scotland today. Methods and Results: Focus group sessions, in the North of Scotland and in the ‘Central Belt’, captured rich qualitative data. A survey, sent to eligible participants on the Spina Bifida National database, offered complimentary data source. Despite the fact that the number of returned questionnaires was low (n = 20), data analysis identified a number of core recurring themes. These include issues concerning Communications, Respect, Choice and Control. Findings suggest that there is a significant chasm between the political rhetoric and the reality faced by young people with spina bifida moving to adult healthcare services. Conclusion: A possible way to facilitate successful transition of young people is using personal healthcare information as the locus for needed change. More research is needed to ascertain whether a ‘Person-Centred Record’, which is set to empower young people on their transition pathway, is an appropriate transition tool

Wind speed statistics for Goldstone, California, anemometer sites

An exploratory wind survey at an antenna complex was summarized statistically for application to future windmill designs. Data were collected at six locations from a total of 10 anemometers. Statistics include means, standard deviations, cubes, pattern factors, correlation coefficients, and exponents for power law profile of wind speed. Curves presented include: mean monthly wind speeds, moving averages, and diurnal variation patterns. It is concluded that three of the locations have sufficiently strong winds to justify consideration for windmill sites

An ion resonance instability in grossly non-neutral plasmas

Ion resonance instability in grossly non-neutral plasma

The Activist Chroniclers of Occupy Gezi: Counterposing Visibility to Injustice

With the benefit of hindsight, this chapter casts another glance at Occupy Gezi, a landmark protest in contemporary Turkey. We reflect on the pursuit of visibility by activists on Twitter as a means to garner the attention of the Turkish and the global public to the heavy-handed police crackdown of the popular mobilization. We interpret their quest for visibility as a subaltern tactic employed to reverse an asymmetry of power through an aesthetics of indignation at the injustice perpetrated against peaceful demonstrators. In the longer run, however, such visibility poses an important dilemma when, as in the case of Turkey, it becomes the basis for reflexive state surveillance

Cuing Collective Outcomes on Twitter: A Qualitative Reading of Movement Social Learning

In this article, we explore the process of movement social learning on Twitter. Previously described as the diffusion and social validation of innovation pertaining to collective outcomes through the practice of retweeting, movement social learning is unpicked with a combination of trace and interview data. We examine language use in retweets associated with the UK People’s Assembly Against Austerity with the aim to form an understanding of how such learning is cued. We argue that retweeters make visible and transmit insights into collective outcomes and ways of attaining them. They maintain a flow of information that sustains a pool of knowledge about the movement. At the same time, they construct a selective discursive environment where the public voicing of conflict can help clarify the scope of participation in a movement

Lorentz Transformation from Symmetry of Reference Principle

The Lorentz Transformation is traditionally derived requiring the Principle of Relativity and light-speed universality. While the latter can be relaxed, the Principle of Relativity is seen as core to the transformation. The present letter relaxes both statements to the weaker, Symmetry of Reference Principle. Thus the resulting Lorentz transformation and its consequences (time dilatation, length contraction) are, in turn, effects of how we manage space and time.Comment: 2 page

Assembly, trafficking and function of gamma-secretase

gamma-Secretase catalyzes the final cleavage of the beta-amyloid precursor protein to generate amyloid-beta peptide, the principal component of amyloid plaques in the brains of patients suffering from Alzheimer's disease. Here, we review the identification of gamma-secretase as a protease complex and its assembly and trafficking to its site(s) of cellular function. In reconstitution experiments, gamma-secretase was found to be composed of four integral membrane proteins, presenilin (PS), nicastrin (NCT), PEN-2 and APH-1 that are essential and sufficient for gamma-secretase activity. PS, which serves as a catalytic subunit of gamma-secretase, was identified as a prototypic member of novel aspartyl proteases of the GxGD type. In human cells, gamma-secretase could be further defined as a heterogeneous activity consisting of distinct complexes that are composed of PS1 or PS2 and APH-1a or APH-1b homologues together with NCT and PEN-2. Using green fluorescent protein as a reporter we localized PS and gamma-secretase activity at the plasma membrane and endosomes. Investigation of gamma-secretase complex assembly in knockdown and knockout cells of the individual subunits allowed us to develop a model of complex assembly in which NCT and APH-1 first stabilize PS before PEN-2 assembles as the last component. Furthermore, we could map domains in PS and PEN-2 that govern assembly and trafficking of the complex. Finally, Rer1 was identified as a PEN-2-binding protein that serves a role as an auxiliary factor for gamma-secretase complex assembly. Copyright (c) 2006 S. Karger AG, Basel

Dynamics of quasiparticle trapping in Andreev levels

We present a theory describing the trapping and untrapping of quasiparticles in the Andreev bound level of a single-channel weak link between two superconductors. We calculate the rates of the transitions between even and odd occupations of the Andreev level induced by absorption and emission of both photons and phonons. We apply the theory to a recent experiment [Phys. Rev. Lett. 106, 257003 (2011)] in which the dynamics of the trapping of quasiparticles in the Andreev levels of superconducting atomic contacts coupled to a Josephson junction was measured. We show that the plasma energy $h\nu_p$ of the Josephson junction defines a rather abrupt transition between a fast relaxation regime dominated by coupling to photons and a slow relaxation regime dominated by coupling to phonons. With realistic parameters the theory provides a semi-quantitative description of the experimental results.Comment: 11 pages, 9 figures. Accepted for publication in Physical Review

Adaptive Investment Strategies For Periodic Environments

In this paper, we present an adaptive investment strategy for environments with periodic returns on investment. In our approach, we consider an investment model where the agent decides at every time step the proportion of wealth to invest in a risky asset, keeping the rest of the budget in a risk-free asset. Every investment is evaluated in the market via a stylized return on investment function (RoI), which is modeled by a stochastic process with unknown periodicities and levels of noise. For comparison reasons, we present two reference strategies which represent the case of agents with zero-knowledge and complete-knowledge of the dynamics of the returns. We consider also an investment strategy based on technical analysis to forecast the next return by fitting a trend line to previous received returns. To account for the performance of the different strategies, we perform some computer experiments to calculate the average budget that can be obtained with them over a certain number of time steps. To assure for fair comparisons, we first tune the parameters of each strategy. Afterwards, we compare the performance of these strategies for RoIs with different periodicities and levels of noise.Comment: Paper submitted to Advances in Complex Systems (November, 2007) 22 pages, 9 figure