Why is the NSW prison population falling?

After steadily increasing for more than a decade, from mid 2009 the NSW prison population started falling. This paper identifies why this has occurred. Method: The study relied upon administrative data. Corrections data was considered to gauge the size, timing and nature of changes in the prison population. Police recorded crime and court data were analysed to measure changes in offending and sentencing which eventually have a bearing on prison numbers. Results: Corrections data showed that the decrease in the prison population was limited to sentenced prisoners and was driven by a reduction in the number of offenders serving sentences for Assault, Break and enter, Theft and Traffic offences. Break and enter, Theft and Assault, prisoners appear to have decreased, in part, because the incidence of these offences have fallen. There have also been moves away from the use of imprisonment as a penalty for each of the four offences whether because fewer offenders are being imprisoned or because the average sentence length has fallen. Conclusion: In 2011, fewer offenders were serving prison sentences for Assault, Break and enter, Theft and Traffic offences. This appears to be due to both a reduction in the number of offenders in court and changes in sentencing practices for certain offences. It is beyond the scope of this paper to ascertain whether changes in sentencing practice reflect a move towards more lenient sentencing or whether they have resulted from changes in the severity of offences themselves. The reduction in the number of offenders for some offences appears to be due, at least in part, to a reduction in the volume of crime

Why is the NSW prison population growing?

This paper provides a preliminary analysis of the rapid rise in the NSW prison population from January 2013 to March 2014. Method: Descriptive analysis of court, crime, arrest and correctional data, and ARIMA modelling of prison trends. Results: The key factors responsible for the recent rise in the NSW prison population appear to be a higher rate of arrest for serious crime and an increase in the proportion of convicted offenders given a prison sentence. There is no evidence that prisoners during 2013 are spending longer in custody but there is evidence the length of stay in custody may increase over the coming year. If the current trend in inmate numbers continues, the NSW prison population will rise by another 17 per cent (i.e., to about 12,500 inmates) by March 2015. Conclusion: Early consideration should be given to measures that reduce the demand for prison accommodation and/or expand prison capacity

Narrative evolution: Learning from students' talk about species variation

Learners do not always enjoy productive interactions with Multimedia Interactive Learning Environments. Their attention can be distracted away from the educational focus intended by designers and teachers through poor design and operational inadequacy. In this paper we describe a study of groups of learners using a multimedia CD-ROM research tool called Galapagos. This tool was developed to enable us to observe groups of learners interacting with different versions of the same multimedia content. These different versions implemented different forms of guidance for learners both within the presented narrative structure of the material and in the tools offered to learners to help them build the individual content elements into a coherent whole. Our empirical work was conducted with groups of learners within their educational establishment using the Galapagos CD-ROM as part of their studies for national examinations in Biology. Their sessions with Galapagos were recorded using video and audio and our analysis of their dialogue has enabled us to gain a greater understanding of the factors that contribute to productive, educationally focused learning interactions. Through the construction of different representations we have been able to coordinate information about interactivity between learners and system at the interface with interactivity between individual learners within the group around the system interface. Varying the quantity and quality of guidance impacts upon the trajectory learners construct through multimedia content; it also influences the manner in which they use the facilities provided by system designers to assist them in their construction of task answers

The 2015 NSW prison population forecast

Prison population forecasting is fraught with difficulty. Many factors affect the size of the prison population, including levels of crime, the number of arrests, the proportion of arrestees convicted, the proportion refused bail, the proportion given a prison sentence, the average length of prison sentences, the proportion of offenders released to parole at the end of their non-parole period and the rate at which parole is revoked. This report provides short and long-term forecasts of the number of prisoners in NSW. Three long-term forecasts are provided; one of which assumes no further growth in age-specific rates of imprisonment, and another two of which assume a continuation of the growth that has occurred either over the last ten years or over the history of available data (32 years), respectively. In order to provide some context for the forecasts we begin by describing long-term trends in the remand and sentenced prisoner numbers and some of the factors that have influenced growth in these populations. Results: The short-term forecast is that, if relevant influences remain unchanged, NSW will have 12,191 prisoners by March 2017. If age-specific rates of imprisonment remain constant, we expect the NSW prison population to rise to 12,500 by June 2036. If age-specific rates of imprisonment rise in a manner commensurate with trends observed over the past decade, the prison population should reach 15,600 by June 2036. If age-specific imprisonment rates rise according to the trends observed since 1982, the prison population should reach 17,600 by June 2036. Conclusion: The NSW prison population is likely to rise over both the short and long-term unless measures are taken to reduce the demand for prison accommodation. &nbsp

Centre-of-mass and internal symmetries in classical relativistic systems

The internal symmetry of composite relativistic systems is discussed. It is demonstrated that Lorentz-Poincar\'e symmetry implies the existence of internal moments associated with the Lorentz boost, which are Laplace-Runge-Lenz (LRL) vectors. The LRL symmetry is thus found to be the internal symmetry universally associated with the global Lorentz transformations, in much the same way as internal spatial rotations are associated with global spatial rotations. Two applications are included, for an interacting 2-body system and for an interaction-free many-body system of particles. The issue of localizability of the relativistic CM coordinate is also discussed

Spinning-particle model for the Dirac equation and the relativistic Zitterbewegung

We construct the relativistic particle model without Grassmann variables which meets the following requirements. A) Canonical quantization of the model implies the Dirac equation. B) The variable which experiences {\it Zitterbewegung}, represents a gauge non-invariant variable in our model. Hence our particle does not experiences the undesirable {\it Zitterbewegung}. C) In the nonrelativistic limit spin is described by three-vector, as it could be expected.Comment: 6 pages, misprints correcte

Quantization of Nonstandard Hamiltonian Systems

The quantization of classical theories that admit more than one Hamiltonian description is considered. This is done from a geometrical viewpoint, both at the quantization level (geometric quantization) and at the level of the dynamics of the quantum theory. A spin-1/2 system is taken as an example in which all the steps can be completed. It is shown that the geometry of the quantum theory imposes restrictions on the physically allowed nonstandard quantum theories.Comment: Revtex file, 23 pages, no figure

Dynamics of test bodies with spin in de Sitter spacetime

We study the motion of spinning test bodies in the de Sitter spacetime of constant positive curvature. With the help of the 10 Killing vectors, we derive the 4-momentum and the tensor of spin explicitly in terms of the spacetime coordinates. However, in order to find the actual trajectories, one needs to impose the so-called supplementary condition. We discuss the dynamics of spinning test bodies for the cases of the Frenkel and Tulczyjew conditions.Comment: 11 pages, RevTex forma

The spectroscopic binary system Gl 375. I. Orbital parameters and chromospheric activity

We study the spectroscopic binary system Gl 375. We employ medium resolution echelle spectra obtained at the 2.15 m telescope at the Argentinian observatory CASLEO and photometric observations obtained from the ASAS database. We separate the composite spectra into those corresponding to both components. The separated spectra allow us to confirm that the spectral types of both components are similar (dMe3.5) and to obtain precise measurements of the orbital period (P = 1.87844 days), minimum masses (M_1 sin^3 i = 0.35 M_sun and M_2 sin^3 i =0.33 M_sun) and other orbital parameters. The photometric observations exhibit a sinusoidal variation with the same period as the orbital period. We interpret this as signs of active regions carried along with rotation in a tidally synchronized system, and study the evolution of the amplitude of the modulation in longer timescales. Together with the mean magnitude, the modulation exhibits a roughly cyclic variation with a period of around 800 days. This periodicity is also found in the flux of the Ca II K lines of both components, which seem to be in phase. The periodic changes in the three observables are interpreted as a sign of a stellar activity cycle. Both components appear to be in phase, which implies that they are magnetically connected. The measured cycle of approximately 2.2 years (800 days) is consistent with previous determinations of activity cycles in similar stars.Comment: 10 pages, including 11 figures and 3 tables. Accepted for publication in Astronomy & Astrophysic

Mathisson's helical motions for a spinning particle --- are they unphysical?

It has been asserted in the literature that Mathisson's helical motions are unphysical, with the argument that their radius can be arbitrarily large. We revisit Mathisson's helical motions of a free spinning particle, and observe that such statement is unfounded. Their radius is finite and confined to the disk of centroids. We argue that the helical motions are perfectly valid and physically equivalent descriptions of the motion of a spinning body, the difference between them being the choice of the representative point of the particle, thus a gauge choice. We discuss the kinematical explanation of these motions, and we dynamically interpret them through the concept of hidden momentum. We also show that, contrary to previous claims, the frequency of the helical motions coincides, even in the relativistic limit, with the zitterbewegung frequency of the Dirac equation for the electron