How Parliament's failure to clearly articulate immigration policy forces judges to take control

Why does the government get defeated so often in immigration cases? Matt Williams explains that the language used in relevant legislation has been increasingly unclear, leaving it up to judges to debate the meaning and intention of policy

Point-Particle Effective Field Theory I: Classical Renormalization and the Inverse-Square Potential

Singular potentials (the inverse-square potential, for example) arise in many situations and their quantum treatment leads to well-known ambiguities in choosing boundary conditions for the wave-function at the position of the potential's singularity. These ambiguities are usually resolved by developing a self-adjoint extension of the original problem; a non-unique procedure that leaves undetermined which extension should apply in specific physical systems. We take the guesswork out of this picture by using techniques of effective field theory to derive the required boundary conditions at the origin in terms of the effective point-particle action describing the physics of the source. In this picture ambiguities in boundary conditions boil down to the allowed choices for the source action, but casting them in terms of an action provides a physical criterion for their determination. The resulting extension is self-adjoint if the source action is real (and involves no new degrees of freedom), and not otherwise (as can also happen for reasonable systems). We show how this effective-field picture provides a simple framework for understanding well-known renormalization effects that arise in these systems, including how renormalization-group techniques can resum non-perturbative interactions that often arise, particularly for non-relativistic applications. In particular we argue why the low-energy effective theory tends to produce a universal RG flow of this type and describe how this can lead to the phenomenon of reaction {\em catalysis}, in which physical quantities (like scattering cross sections) can sometimes be surprisingly large compared to the underlying scales of the source in question. We comment in passing on the possible relevance of these observations to the phenomenon of the catalysis of baryon-number violation by scattering from magnetic monopoles.Comment: LaTeX, 20 pages plus appendi

State of the water sector report 2015

The Australian Water Association and Deloitte are pleased to present the State of the Water Sector Report 2015. The Report is the only one of its kind, reporting on the trends and insights of water sector professionals about their own industry. The survey results reveal attitudes and behaviours relating to a range of topics affecting the industry. This year marks the fifth year that the survey has been run and, as such, a summary of trends across the five years has been included in this year’s report. Trends observed over the last five years operational efficiency first emerged as an issue affecting the water sector in 2013, due to growing concerns about the need to control costs and demonstrate value for money, both within the sector itself and for customers. This rose to become the primary issue and area of concern in 2014 as operational costs continued to rise and new capital investment costs were being passed on to customers. In 2015 operational efficiency remains the second biggest issue for the industry, with efficiencies still to be gained through asset management, process improvement and works management and systems improvement. Skills shortages, and talent attraction and retention were of significant concern when the survey commenced five years ago, with the issue of ageing workforces in particular seen by many as a looming threat for the industry. However, in more recent years these concerns have almost halved due to a reduction in demand for additional staff and the greater availability of skilled labour, given construction activity in the mining industry has eased. Unconventional gas came onto the industry’s radar in 2012. last year, 70% of respondents stated that they believed unconventional gas had a significant to moderate effect on the overall management of ground- or surface water. In 2015, 55% of respondents stated that produced water from unconventional gas activities can be treated to a suitable quality for irrigation and other purposes, nevertheless highlighting some concerns in relation to the oil and gas sector impact. Although climate change was identified by 86% of respondents last year as posing a significant or moderate risk to sustainable management of water, sustainability is rated as less important than in previous years, with it being ranked as one of the top issues for the sector in 2011. This may be due to broader changes in community sentiment regarding environmental issues, and more benign weather conditions. While the sector believed security of supply was being managed well, climate change, as well as population growth, is viewed as one of the greatest challenges over the next five years. from a price and regulatory perspective, satisfaction with the role of economic regulators continues to increase slowly, and an increasing proportion of respondents support regulators making deterministic decisions on prices, rather than just monitoring prices. However, a price monitoring role is still favoured by more than three times as many respondents as deterministic pricing. 2015 Key issues The price of water and water regulation Water sector professionals’ perceptions of customer beliefs Sources of water Digital technology Asset management and operational efficiency -- State based reports are also available at AWA\u27s websit

Champagne Flutes and Brandy Snifters: Modelling Protostellar Outflow-Cloud Chemical Interfaces

A rich variety of molecular species has now been observed towards hot cores in star forming regions and in the interstellar medium. An increasing body of evidence from millimetre interferometers suggests that many of these form at the interfaces between protostellar outflows and their natal molecular clouds. However, current models have remained unable to explain the origin of the observational bias towards wide-angled "brandy snifter" shaped outflows over narrower "champagne flute" shapes in carbon monoxide imaging. Furthermore, these wide-angled systems exhibit unusually high abundances of the molecular ion HCO$^+$. We present results from a chemo-dynamic model of such regions where a rich chemistry arises naturally as a result of turbulent mixing between cold, dense molecular gas and the hot, ionized outflow material. The injecta drives a rich and rapid ion-neutral chemistry in qualitative and quantitative agreement with the observations. The observational bias towards wide-angled outflows is explained naturally by the geometry-dependent ion injection rate causing rapid dissociation of CO in the younger systems.Comment: Accepted to MNRAS. 12 pages, 8 Figure

Micropalaeontology reveals the source of building materials for a defensive earthwork (English Civil War?) at Wallingford Castle, Oxfordshire

Microfossils recovered from sediment used to construct a putative English Civil War defensive bastion at Wallingford Castle, south Oxfordshire, provide a biostratigraphical age of Cretaceous (earliest Cenomanian) basal M. mantelli Biozone. The rock used in the buttress – which may have housed a gun emplacement – can thus be tracked to the Glauconitic Marl Member, base of the West Melbury Marly Chalk Formation. A supply of this rock is available on the castle site or to the east of the River Thames near Crowmarsh Gifford. Microfossils provide a unique means to provenance construction materials used at the Wallingford site. While serendipity may have been the chief cause for use of the Glauconitic Marl, when compacted, it forms a strong, almost ‘road base’-like foundation that was clearly of use for constructing defensive works. Indeed, use of the Glauconitic Marl was widespread in the area for agricultural purposes and its properties may have been well-known locally

Point-Particle Effective Field Theory II: Relativistic Effects and Coulomb/Inverse-Square Competition

We apply point-particle effective field theory (PPEFT) to compute the leading shifts due to finite-size source effects in the Coulomb bound energy levels of a relativistic spinless charged particle. This is the analogue for spinless electrons of the contribution of the charge-radius of the source to these levels, and we disagree with standard calculations in several ways. Most notably we find there are two effective interactions with the same dimension that contribute to leading order in the nuclear size. One is the standard charge-radius contribution, while the other is a contact interaction whose leading contribution to $\delta E$ arises linearly in the small length scale, $\epsilon$, characterizing the finite-size effects, and is suppressed by $(Z\alpha)^5$. We argue that standard calculations miss the contributions of this second operator because they err in their choice of boundary conditions at the source for the wave-function of the orbiting particle. PPEFT predicts how this boundary condition depends on the source's charge radius, as well as on the orbiting particle's mass. Its contribution turns out to be crucial if the charge radius satisfies $\epsilon \lesssim (Z\alpha)^2 a_B$, with $a_B$ the Bohr radius, since then relativistic effects become important. We show how the problem is equivalent to solving the Schr\"odinger equation with competing Coulomb, inverse-square and delta-function potentials, which we solve explicitly. A similar enhancement is not predicted for the hyperfine structure, due to its spin-dependence. We show how the charge-radius effectively runs due to classical renormalization effects, and why the resulting RG flow is central to predicting the size of the energy shifts. We discuss how this flow is relevant to systems having much larger-than-geometric cross sections, and the possible relevance to catalysis of reactions through scattering with monopoles.Comment: LaTeX, 22 pages plus appendices, v3: revised appendices, made more precise and concise discussion about proton radius for mesonic system

Local government authority attitudes to road traffic CO₂ emissions modelling: a British case study

Local government authorities (LGAs) play a key role in facilitating mitigation of road traffic CO2 emissions and must engage in emissions modelling to quantify the impact of transport interventions. Existing Emissions Model (EM) methodologies range from aggregate to disaggregate approaches, with more detail normally entailing more resources. However, it is not clear which approaches LGAs actually utilise. This article reports results of a survey designed to discover the level of detail considered practical by British LGAs (n = 34). Results show that resource scarcity is important, with particular importance attached to EM reusability and convenient input data sources. Most LGA EMs use traffic variable inputs (predominantly traffic flow and traffic average speed), with this approach being the best-fit for LGA resources. Link-by-link sources of data rated highly for convenience are road traffic models and urban traffic control systems

Optical vortex generation from molecular chromophore arrays

The generation of light endowed with orbital angular momentum, frequently termed optical vortex light, is commonly achieved by passing a conventional beam through suitably constructed optical elements. This Letter shows that the necessary phase structure for vortex propagation can be directly produced through the creation of twisted light from the vacuum. The mechanism is based on optical emission from a family of chromophore nanoarrays that satisfy specific geometric and symmetry constraints. Each such array can support pairs of electronically delocalized doubly degenerate excitons whose azimuthal phase progression is responsible for the helical wave front of the emitted radiation. The exciton symmetry dictates the maximum magnitude of topological charge; detailed analysis secures the conditions necessary to deliver optical vortices of arbitrary order