Neural network interpolation of the magnetic field for the LISA Pathfinder Diagnostics Subsystem

LISA Pathfinder is a science and technology demonstrator of the European Space Agency within the framework of its LISA mission, which aims to be the first space-borne gravitational wave observatory. The payload of LISA Pathfinder is the so-called LISA Technology Package, which is designed to measure relative accelerations between two test masses in nominal free fall. Its disturbances are monitored and dealt by the diagnostics subsystem. This subsystem consists of several modules, and one of these is the magnetic diagnostics system, which includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at the positions of the test masses. However, since the magnetometers are located far from the positions of the test masses, the magnetic field at their positions must be interpolated. It has been recently shown that because there are not enough magnetic channels, classical interpolation methods fail to derive reliable measurements at the positions of the test masses, while neural network interpolation can provide the required measurements at the desired accuracy. In this paper we expand these studies and we assess the reliability and robustness of the neural network interpolation scheme for variations of the locations and possible offsets of the magnetometers, as well as for changes in environmental conditions. We find that neural networks are robust enough to derive accurate measurements of the magnetic field at the positions of the test masses in most circumstances

On Kedlaya type inequalities for weighted means

In 2016 we proved that for every symmetric, repetition invariant and Jensen concave mean $\mathscr{M}$ the Kedlaya-type inequality $$\mathscr{A}\big(x_1,\mathscr{M}(x_1,x_2),\ldots,\mathscr{M}(x_1,\ldots,x_n)\big)\le \mathscr{M} \big(x_1, \mathscr{A}(x_1,x_2),\ldots,\mathscr{A}(x_1,\ldots,x_n)\big)$$ holds for an arbitrary $(x_n)$ ($\mathscr{A}$ stands for the arithmetic mean). We are going to prove the weighted counterpart of this inequality. More precisely, if $(x_n)$ is a vector with corresponding (non-normalized) weights $(\lambda_n)$ and $\mathscr{M}_{i=1}^n(x_i,\lambda_i)$ denotes the weighted mean then, under analogous conditions on $\mathscr{M}$, the inequality $$\mathscr{A}_{i=1}^n \big(\mathscr{M}_{j=1}^i (x_j,\lambda_j),\:\lambda_i\big) \le \mathscr{M}_{i=1}^n \big(\mathscr{A}_{j=1}^i (x_j,\lambda_j),\:\lambda_i\big)$$ holds for every $(x_n)$ and $(\lambda_n)$ such that the sequence $(\frac{\lambda_k}{\lambda_1+\cdots+\lambda_k})$ is decreasing.Comment: J. Inequal. Appl. (2018

Geophysical studies with laser-beam detectors of gravitational waves

The existing high technology laser-beam detectors of gravitational waves may find very useful applications in an unexpected area - geophysics. To make possible the detection of weak gravitational waves in the region of high frequencies of astrophysical interest, ~ 30 - 10^3 Hz, control systems of laser interferometers must permanently monitor, record and compensate much larger external interventions that take place in the region of low frequencies of geophysical interest, ~ 10^{-5} - 3 X 10^{-3} Hz. Such phenomena as tidal perturbations of land and gravity, normal mode oscillations of Earth, oscillations of the inner core of Earth, etc. will inevitably affect the performance of the interferometers and, therefore, the information about them will be stored in the data of control systems. We specifically identify the low-frequency information contained in distances between the interferometer mirrors (deformation of Earth) and angles between the mirrors' suspensions (deviations of local gravity vectors and plumb lines). We show that the access to the angular information may require some modest amendments to the optical scheme of the interferometers, and we suggest the ways of doing that. The detailed evaluation of environmental and instrumental noises indicates that they will not prevent, even if only marginally, the detection of interesting geophysical phenomena. Gravitational-wave instruments seem to be capable of reaching, as a by-product of their continuous operation, very ambitious geophysical goals, such as observation of the Earth's inner core oscillations.Comment: 29 pages including 8 figures, modifications and clarifications in response to referees' comments, to be published in Class. Quant. Gra

Turning collegial governance on its head : symbolic violence, hegemony and the academic board

This article draws on Bourdieu’s theorisation of domination and Gramsci’s notions of hegemony within the context of a larger empirical study of Australian university academic governance, and of academic boards (also known as academic senates or faculty senates) in particular. Reporting data that suggest a continued but radically altered form of collegial governance in which hegemony is exercised by management rather than by the professor, it theorises the domination of academic boards within western democratic universities. However, traditional collegial governance is also dependent upon a community of scholars, a role historically played by the academic board. In view of the suggested transition in collegial governance and the resultant convergence of academic work and management, the article concludes with questions about whether academic boards can continue to serve as communities of scholars in future

Youth Gambling: The health and wellbeing of New Zealand secondary school students in 2012

Gambling has become a widely available activity in today’s society (Hardoon & Derevensky, 2002; Turchi & Derevensky, 2006). In fact, many researchers “have noted that an entire generation has now grown up in an era when lottery and casino gambling is widely available and heavily advertised” (Volberg, Gupta, Griffiths, Ólason, & Delfabbro, 2010, p. 3). Evidence suggests that it has become a popular past-time not only for adults, but also for children and young people (Derevensky & Gupta, 2000; Gupta & Derevensky, 1998a; Hardoon & Derevensky, 2002; Jacobs, 2000; Splevins, Mireskandari, Clayton, & Blaszczynski, 2010; Turchi & Derevensky, 2006). Moreover, research indicates that gambling is one of the first risky activities that adolescents become involved with (i.e. they begin gambling prior to experimentation with alcohol, drugs, sexual behaviour) (Volberg, et al., 2010). Whilst for many youth involvement in gambling does not result in problematic behaviour, others go on to experience serious problems (Dickson, Derevensky, & Gupta, 2003). A vast range of adolescent gambling prevalence studies that have been undertaken over the past 25 years, across different countries, and incorporating general populations as well as youth specifically. Rates of youth problem gambling have often been found to be higher than the rates identified for adults (Huang & Boyer, 2007; Shaffer & Hall, 1996; Welte, Barnes, Tidwell, & Hoffman, 2008; Williams, Page, Parke, & Rigbye, 2008), with some estimating them to be more than double those of adults (Gupta & Derevensky, 1998a; Jackson, Dowling, Thomas, Bond, & Patton, 2008; Lesieur, et al., 1991), or up to three times as high (Rigbye, 2010). However, it has also been recognised that there is far less research in this field compared to that which has explored other youth risk behaviours such as substance use (Blinn-Pike, Worthy, & Jonkman, 2010). The gap in New Zealand-based information regarding prevalence of youth gambling has been identified previously (Bellringer, et al., 2003; Rossen, Tse, & Vaidya, 2009) and in 2003 it was recommended that research be undertaken to measure the involvement of New Zealand youth in gambling as well as associated factors and gambling-related problems (Bellringer, et al., 2003). A limited body of research has since employed various sources of data to consider youth gambling in New Zealand (e.g. Gray, 2010; Ministry of Health, 2008, 2009; Rossen, 2008; Rossen, Butler, & Denny, 2011). An extremely valuable source of information on New Zealand youth is the University of Auckland’s (UoA) National youth health and wellbeing surveys. To date, the UoA’s Adolescent Health Research Group (AHRG) has completed three National youth health and wellbeing surveys. The Youth2000 Survey Series aim to provide nationally representative information on the health and wellbeing of young people attending New Zealand secondary schools. The Survey Series includes a wide range of questions about issues that contribute to the health and wellbeing of young people (such as substance use, injuries and violence, home and family) and allow researchers to take an ecological approach to identifying overall risk and protective factors in young people’s lives. Youth’12, a survey of 8,500 secondary school students throughout New Zealand, is the most recent survey to be undertaken by the AHRG. The inclusion of gambling items in the Youth’12 survey provides a unique opportunity to examine the impacts of gambling and problem gambling on secondary school students throughout New Zealand within an ecological framework. This report was commissioned by the Ministry of Health and begins with a comprehensive review of the local and international youth gambling literature, followed by an overview of the Youth2000 Survey Series and methodology for Youth’12. A thorough analysis of Youth’12 gambling items was undertaken with results being reported under the following eight categories (detailed results for each set of analyses are also provided in the appendices): - Students and their own gambling (Section Five); - Unhealthy gambling amongst students (Section Six); - Attitudes and motivating factors towards gambling (Section Seven); - The impacts of others’ gambling on students (Section Eight); and, - Risk and protective factors for student gambling (Section Nine); - Gambling and Māori taitamariki in Aotearoa (Section 10); - Gambling and Pacific young people in New Zealand (Section 11); and, - Gambling and Asian young people in New Zealand (Section 12). Finally, a discussion chapter provides an overview of the findings and implications

Reaction Between Nitrogen and Spinel in Chromium

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66029/1/j.1151-2916.1968.tb15671.x.pd

Educating public health physicians for the future: a current perspective from Aotearoa New Zealand

Persisting, and in some cases widening, inequalities in health within and between countries present significant challenges to the focus and practice of contemporary public health, and by association, to public health education. As public health physicians and academic educators of medically- and non-medically trained public health practitioners, we call for a radical re-think of current approaches to public health medicine education and training in order to address these challenges. The public health physicians of the future, we argue, require not merely technical knowledge and skills but also a set of values that underpin a commitment to ethical principles, social equity, human rights, compassionate action, advocacy and leadership. Furthermore, while they will need to have their action firmly grounded in local realities they should think, if not speak and act, from an informed awareness of global issues. Drawing from our experience in Aotearoa New Zealand, as well as with marginalised communities overseas, we proffer our suggestions for the process and content of public health physician education and training for the future, with the intention of stimulating debate

Solar System Processes Underlying Planetary Formation, Geodynamics, and the Georeactor

Only three processes, operant during the formation of the Solar System, are responsible for the diversity of matter in the Solar System and are directly responsible for planetary internal-structures, including planetocentric nuclear fission reactors, and for dynamical processes, including and especially, geodynamics. These processes are: (i) Low-pressure, low-temperature condensation from solar matter in the remote reaches of the Solar System or in the interstellar medium; (ii) High-pressure, high-temperature condensation from solar matter associated with planetary-formation by raining out from the interiors of giant-gaseous protoplanets, and; (iii) Stripping of the primordial volatile components from the inner portion of the Solar System by super-intense solar wind associated with T-Tauri phase mass-ejections, presumably during the thermonuclear ignition of the Sun. As described herein, these processes lead logically, in a causally related manner, to a coherent vision of planetary formation with profound implications including, but not limited to, (a) Earth formation as a giant gaseous Jupiter-like planet with vast amounts of stored energy of protoplanetary compression in its rock-plus-alloy kernel; (b) Removal of approximately 300 Earth-masses of primordial gases from the Earth, which began Earth's decompression process, making available the stored energy of protoplanetary compression for driving geodynamic processes, which I have described by the new whole-Earth decompression dynamics and which is responsible for emplacing heat at the mantle-crust-interface at the base of the crust through the process I have described, called mantle decompression thermal-tsunami; and, (c)Uranium accumulations at the planetary centers capable of self-sustained nuclear fission chain reactions.Comment: Invited paper for the Special Issue of Earth, Moon and Planets entitled Neutrino Geophysics Added final corrections for publicatio

Biogenesis of the inner membrane complex is dependent on vesicular transport by the alveolate specific GTPase Rab11B

Apicomplexan parasites belong to a recently recognised group of protozoa referred to as Alveolata. These protists contain membranous sacs (alveoli) beneath the plasma membrane, termed the Inner Membrane Complex (IMC) in the case of Apicomplexa. During parasite replication the IMC is formed de novo within the mother cell in a process described as internal budding. We hypothesized that an alveolate specific factor is involved in the specific transport of vesicles from the Golgi to the IMC and identified the small GTPase Rab11B as an alveolate specific Rab-GTPase that localises to the growing end of the IMC during replication of Toxoplasma gondii. Conditional interference with Rab11B function leads to a profound defect in IMC biogenesis, indicating that Rab11B is required for the transport of Golgi derived vesicles to the nascent IMC of the daughter cell. Curiously, a block in IMC biogenesis did not affect formation of sub-pellicular microtubules, indicating that IMC biogenesis and formation of sub-pellicular microtubules is not mechanistically linked. We propose a model where Rab11B specifically transports vesicles derived from the Golgi to the immature IMC of the growing daughter parasites