Pan-STARRS1 Discovery of Two Ultraluminous Supernovae at z ≈ 0.9

We present the discovery of two ultraluminous supernovae (SNe) at z ≈ 0.9 with the Pan-STARRS1 Medium Deep Survey. These SNe, PS1-10ky and PS1-10awh, are among the most luminous SNe ever discovered, comparable to the unusual transients SN 2005ap and SCP 06F6. Like SN 2005ap and SCP 06F6, they show characteristic high luminosities (M_(bol) ≈ –22.5 mag), blue spectra with a few broad absorption lines, and no evidence for H or He. We have constructed a full multi-color light curve sensitive to the peak of the spectral energy distribution in the rest-frame ultraviolet, and we have obtained time series spectroscopy for these SNe. Given the similarities between the SNe, we combine their light curves to estimate a total radiated energy over the course of explosion of (0.9-1.4) × 10^(51) erg. We find photospheric velocities of 12,000-19,000 km s^(–1) with no evidence for deceleration measured across ~3 rest-frame weeks around light curve peak, consistent with the expansion of an optically thick massive shell of material. We show that, consistent with findings for other ultraluminous SNe in this class, radioactive decay is not sufficient to power PS1-10ky, and we discuss two plausible origins for these events: the initial spin-down of a newborn magnetar in a core-collapse SN, or SN shock breakout from the dense circumstellar wind surrounding a Wolf-Rayet star

Unbounded-Error Classical and Quantum Communication Complexity

Since the seminal work of Paturi and Simon \cite[FOCS'84 & JCSS'86]{PS86}, the unbounded-error classical communication complexity of a Boolean function has been studied based on the arrangement of points and hyperplanes. Recently, \cite[ICALP'07]{INRY07} found that the unbounded-error {\em quantum} communication complexity in the {\em one-way communication} model can also be investigated using the arrangement, and showed that it is exactly (without a difference of even one qubit) half of the classical one-way communication complexity. In this paper, we extend the arrangement argument to the {\em two-way} and {\em simultaneous message passing} (SMP) models. As a result, we show similarly tight bounds of the unbounded-error two-way/one-way/SMP quantum/classical communication complexities for {\em any} partial/total Boolean function, implying that all of them are equivalent up to a multiplicative constant of four. Moreover, the arrangement argument is also used to show that the gap between {\em weakly} unbounded-error quantum and classical communication complexities is at most a factor of three.Comment: 11 pages. To appear at Proc. ISAAC 200

C2O and Frontyard: hacking the archives to design community spaces in Surabaya and Sydney

© 2019, Luke Bacon, Kathleen Azali, Alexandra Lara Crosby and Benjamin Forster. Purpose: The purpose of this study is to identify shared themes and concerns of two local and critical archives by comparing their design and day-to-day practice. Design/methodology/approach: The action research has drawn on the experience of collaboration between a Sydney-based community space (Frontyard) and the Surabaya-based co-working community (C2O) over one year. Each space houses a small physical library of books, which is the focus of this analysis. Findings: Hacking has emerged as a key value of both archives. A hacking approach has shaped the design of each space and the organisation each archive. Hacking frames the analysis of each collection in this study. Practical implications: Pragmatic and political understanding of such archives have implications for better quality and more authentic exchange between the communities that make use of these libraries in Indonesia and Australia. Originality/value: While some work on local critical archives has been done in Indonesia and Australia, no research to date has made specific comparisons with the aim of sharing knowledge. Because these archives are often temporary and ephemeral, documenting the work that goes into them, and their practitioners’ perspectives, is urgent, making possible shared knowledge that can inform the ways communities make decisions about their own heritage

Neurodynamic Evidence Supports a Forced-Excursion Model of Decision-Making under Speed/Accuracy Instructions

Evolutionary pressures suggest that choices should be optimised to maximise rewards, by appropriately trading speed for accuracy. This speed-accuracy tradeoff (SAT) is commonly explained by variation in just the baseline-to-boundary distance, i.e. excursion, of accumulation-to-bound models of perceptual decision making. However, neural evidence is not consistent with this explanation. A compelling account of speeded choice should explain both overt behaviour and the full range of associated brain signatures. Here, we reconcile seemingly contradictory behavioural and neural findings. In two variants of the same experiment, we triangulated upon the neural underpinnings of the SAT in the human brain using both EEG and TMS. We found that distinct neural signals, namely the ERP centroparietal positivity (CPP) and a smoothed motor-evoked potential (MEP) signal, which have both previously been shown to relate to decision-related accumulation, revealed qualitatively similar average neurodynamic profiles with only subtle differences between SAT conditions. These signals were then modelled from behaviour by either incorporating traditional boundary variation or utilising a forced excursion. These model variants are mathematically equivalent, in terms of their behavioural predictions, hence providing identical fits to correct and erroneous reaction time distributions. However, the forced-excursion version instantiates SAT via a more global change in parameters and implied neural activity, a process conceptually akin to, but mathematically distinct from, urgency. This variant better captured both ERP and MEP neural profiles, suggesting that the SAT may be implemented via neural gain modulation, and reconciling standard modelling approaches with human neural data

Polarization fluctuations in insulators and metals: New and old theories merge

The ground-state fluctuation of polarization P is finite in insulators and divergent in metals, owing to the SWM sum rule [I. Souza, T. Wilkens, and R. M. Martin, Phys. Rev. B 62, 1666 (2000)]. This is a virtue of periodic (i.e. transverse) BCs. I show that within any other boundary conditions the P fluctuation is finite even in metals, and a generalized sum rule applies. The boundary-condition dependence is a pure correlation effect, not present at the independent-particle level. In the longitudinal case div P = -rho, and one equivalently addresses charge fluctuations: the generalized sum rule reduces then to a well known result of many-body theory.Comment: 4 pages, no figur

Breakdown of Hydrodynamic Transport Theory in the Ordered Phase of Helimagnets

It is shown that strong fluctuations preclude a hydrodynamic description of transport phenomena in helimagnets, such as MnSi, at T>0. This breakdown of hydrodynamics is analogous to the one in chiral liquid crystals. Mode-mode coupling effects lead to infinite renormalizations of various transport coefficients, and the actual macroscopic description is nonlocal. At T=0 these effects are weakened due to the fluctuation-dissipation theorem, and the renormalizations remain finite. Observable consequences of these results, as manifested in the neutron scattering cross-section, are discussedComment: 4pp., 1 eps figur

Evaluating the environmental impact of crude glycerol purification derived from biodiesel production: A comparative life cycle assessment study

In recent decades, surplus crude glycerol has been generated in large amounts as a waste product of biodiesel production, leading to bottlenecks in the supply chain of the biodiesel industry. This waste glycerol represents an important potential renewable feedstock and platform chemical; however, its purification is often needed for further processing. Advancements towards glycerol purification are being made using sustainable purification techniques aimed at improving the biodiesel industry's environmental footprint. Many studies focussing on various techniques to purify glycerol can be found in the literature; however, very few studies to evaluate the environmental impacts of the purification processes have been reported. This paper provides a critical investigation on the cradle-to-gate life cycle assessment (LCA) of three different processes for purifying crude glycerol, namely, physicochemical treatment and membrane purification (PMP) processes, vacuum distillation purification (VDP) processes and ion exchange purification (IEP) processes having a functional unit (FU) of 1000 kg of purified glycerol. These purification processes were modelled using Aspen plus software v12.1 in combination with Super Pro Designer v13. CCaLC2 (Carbon Calculations over the Life Cycle of Industrial Activities) was used to measure the environmental impacts associated with each process. By following the ISO 14044:2006 methodology and utilising the CCaLC2 tool, seven different types of potential environmental impacts have been investigated, which include carbon footprint, water footprint, acidification, eutrophication, ozone layer depletion, photochemical smog and human toxicity. Sensitivity analysis of the LCA was carried out using the response surface method (RSM) to determine the most effective parameter within the LCA. The total carbon footprint of the PMP, VDP and IEP processes are 3466.82, 1745.72 and 2239.71 kg CO2 eq. FU−1 respectively. The LCA study determined that waste generated as a result of crude glycerol impurities from the three processes had one of the highest environmental impacts on the overall process. For the PMP and IEP processes, the raw materials used in the physicochemical treatment also contribute significantly to the carbon footprint and other environmental impacts. Lastly, aspects concerning the environmental impacts from the PMP glycerol purification process have been addressed by analysing the raw materials from different sources accompanied by altered waste disposal methods (i.e. the incineration of generated wastes as opposed to landfilling) in an attempt to reduce the overall environmental impacts. For the PMP process, which has the highest carbon footprint, usage of differently sourced raw materials and altered waste disposal treatments resulted in 39% reduction in total carbon footprint and 54% reduction in the total ozone layer depletion. Sensitivity analysis of the LCA shows that the glycerol content within the crude glycerol was the most significant parameter

The Effects of Lesions in the Dorsolateral Pons on the Coordination of Swallowing and Breathing in Awake Goats

The purpose of this retrospective study was to gain insight into the contribution of the dorsolateral pons to the coordination of swallowing and breathing in awake goats. In 4 goats, cannulas were chronically implanted bilaterally through the lateral (LPBN) and medial (MPBN) parabrachial nuclei just dorsal to the Kölliker–Fuse nucleus (KFN). After \u3e2 weeks recovery from this surgery, the goats were studied for 5½ h on a control day, and on separate days after receiving 1 and 10 μl injections of ibotenic acid (IA) separated by 1 week. The frequency of swallows did not change during the control and 1 μl IA studies, but after injection of 10 μl IA, there was a transient 65% increase in frequency of swallows (P \u3c 0.05). Under control conditions swallows occurred throughout the respiratory cycle, where late-E swallows accounted for 67.6% of swallows. The distribution of swallow occurrence throughout the respiratory cycle was unaffected by IA injections. Consistent with the concept that swallowing is dominant over breathing, we found that swallows increased inspiratory (TI) and expiratory (TE) time and decreased tidal volume (VT) of the breath of the swallow (n) and/or the subsequent (n + 1) breath. Injections of 10 μl IA attenuated the normal increases in TI and TE and further attenuated VT of the n breath. Additionally, E and I swallows reset respiratory rhythm, but injection of 1 or 10 μl IA progressively attenuated this resetting, suggesting a decreased dominance over respiratory motor output with increasing IA injections. Post mortem histological analysis revealed about 50% fewer (P \u3c 0.05) neurons remained in the KFN, LPBN, and MPBN in lesioned compared to control goats. We conclude that dorsolateral pontine nuclei have a modulatory role in a hypothesized holarchical neural network regulating swallowing and breathing particularly contributing to the normal dominance of swallowing over breathing in both rhythm and motor pattern generation