Evaluating Lossy Collections for Java Applications

We propose to remove live objects from near-full heaps to reduce memory pressure. We modify Java Collections to enable lossy behavior. Some DaCapo benchmarks tolerate an amount of live data loss

Weak plaquette valence bond order in the S=1/2S=1/2 honeycomb J1−J2J_1-J_2 Heisenberg model

Using the density matrix renormalization group, we investigate the $S=1/2$ Heisenberg model on the honeycomb lattice with first- ($J_1$) and second-neighbor ($J_2$) interactions. We are able to study long open cylinders with widths up to 12 lattice spacings. For $J_2/J_1$ near 0.3, we find an apparently paramagnetic phase, bordered by an antiferromagnetic phase for $J_2\lesssim 0.26$ and by a valence bond crystal for $J_2\gtrsim 0.36$. The longest correlation length that we find in this intermediate phase is for plaquette valence bond (PVB) order. This correlation length grows strongly with cylinder circumference, indicating either quantum criticality or weak PVB order.Comment: 9 pages, 15 figures, minor changes are made for publication in Phys. Rev. Let

Unexpected z-Direction Ising Antiferromagnetic Order in a frustrated Spin-1/2 J1−J2J_1-J_2 XY Model on the Honeycomb Lattice

Using the density matrix renormalization group (DMRG) on wide cylinders, we study the phase diagram of the spin-1/2 XY model on the honeycomb lattice, with first-neighbor ($J_1 = 1$) and frustrating second-neighbor ($J_2>0$) interactions. For the intermediate frustration regime $0.22\lesssim J_2\lesssim0.36$, we find a surprising antiferromagnetic Ising phase, with ordered moments pointing along the z axis, despite the absence of any S_z_z interactions in the Hamiltonian. Surrounding this phase as a function of $J_2$ are antiferromagnetic phases with the moments pointing in the $x-y$ plane for small $J_2$ and a close competition between an $x-y$ plane magnetic collinear phase and a dimer phase for large values of $J_2$. We do not find any spin liquid phases in this model.Comment: 5 pages, 5 figures, minor changes made for publication on PR

Global water: issues and insights

This book brings together some of the world’s leading water researchers with an especially written collection of chapters on: water economics; transboundary water; water and development; water and energy; and water concepts. Introduction Freshwater governance holds a prominent position in the global policy agenda. Burgeoning water demand due to population growth and rising incomes is combining with supply-side pressures, such as environmental pollution and climate change, to create acute conditions of global water scarcity. This is a major concern because water is a primary input for agriculture, manufacturing, environmental health, human health, energy production and just about every economic sector and ecosystem. In addition to its importance, the management of freshwater resources is a complex, multidisciplinary topic. Encompassing a range of fields in the physical and social sciences, the task of sustainably meeting human and environmental water needs requires a depth and breadth of understanding unparalleled by most other policy problems. Our objective in this volume is to provide knowledge and insights into major issues and concepts related to freshwater governance. The book is divided into five themed parts: Economics, Transboundary governance, Development, Energy and Water Concepts. A part addresses each theme and opens with an introduction that provides an overview of key topics. For example, the introduction to the economics section presents two main foci: measuring the value of water and managing trade-offs between different water uses. The thematic case studies discuss issues such as water pricing in Organisation for Economic Co-operation and Development (OECD) countries, finance of water supply and irrigation infrastructure and improving agricultural production with enhanced water management. The aim of the volume is to accessibly communicate academic research from the many fields of freshwater governance. Too often, academic research is paywalled and/or written in a style that caters to colleagues in the same field, rather than a broader audience from other disciplines, the policy-making community and the general public. This open-access book presents the research of a range of global experts on freshwater governance in brief, insightful chapters that do not presume a high level of pre-existing knowledge of their respective subjects. This format is intended to present knowledge on the key problems of and solutions to global freshwater challenges. The final part presents research from several United Nations Educational, Social, and Cultural Organisation (UNESCO) supported water research Chairs and Centres. Support and coordination of the insititutions highlighted in this part of the book is provided by UNESCO. One water research Chair is The Australian National University – UNESCO Chair in Water Economics and Transboundary Governance, which was established in April 2010 and works with partners in southern Africa, UNESCO, the Global Water Partnership and other organisations to: (1) increase the skills, capacity, networks and potential of leaders and prospective water managers and policy-makers; (2) sustain and strengthen institutional capacity (especially in southern Africa) by providing a platform for collaboration and institutional development; and, (3) develop innovative research, tools, case-studies, and insights on water economics, water governance and equity. Established by the ANU–UNESCO Chair, the Global Water Forum (GWF) seeks to disseminate knowledge regarding freshwater governance and build the capacity of students, policy-makers and the general public to respond to local and global water issues. The GWF publishes accessible, subscription-free articles highlighing the latest research and practice concerning freshwater governance. A broad range of water-related topics are discussed in a non-technical manner, including water security, development, agriculture, energy and environment. In addition to publishing articles, reports and books, the GWF is engaged in a range of activities, such as the annual Emerging Scholars Award and hosting a portal to educational resources on freshwater. We hope that you enjoy reading this book and, more importantly, gain an improved understanding of the complex freshwater-governance challenges facing us all on a global scale and at a local level

Missing data in randomized controlled trials testing palliative interventions pose a significant risk of bias and loss of power: a systematic review and meta-analyses

Objectives To assess the risk posed by missing data (MD) to the power and validity of trials evaluating palliative interventions. Study Design and Setting A systematic review of MD in published randomized controlled trials (RCTs) of palliative interventions in participants with life-limiting illnesses was conducted, and random-effects meta-analyses and metaregression were performed. CENTRAL, MEDLINE, and EMBASE (2009-2014) were searched with no language restrictions. Results One hundred and eight RCTs representing 15,560 patients were included. The weighted estimate for MD at the primary endpoint was 23.1% (95% confidence interval [CI] 19.3, 27.4). Larger MD proportions were associated with increasing numbers of questions/tests requested (odds ratio [OR] , 1.19; 95% CI 1.05, 1.35) and with longer study duration (OR, 1.09; 95% CI 1.02, 1.17). Meta-analysis found evidence of differential rates of MD between trial arms, which varied in direction (OR, 1.04; 95% CI 0.90, 1.20; I 2 35.9, P = 0.001). Despite randomization, MD in the intervention arms (vs. control) were more likely to be attributed to disease progression unrelated to the intervention (OR, 1.31; 95% CI 1.02, 1.69). This was not the case for MD due to death (OR, 0.92; 95% CI 0.78, 1.08). Conclusion The overall proportion and differential rates and reasons for MD reduce the power and potentially introduce bias to palliative care trials

X-Ray Emission from M32: X-Ray Binaries or a micro-AGN?

We have analysed archival {\it ROSAT} PSPC data for M32 in order to study the x-ray emission from this nearest elliptical galaxy. We fit spectra from three long exposures with Raymond-Smith, thermal bremsstrahlung, and power-law models. All models give excellent fits. The thermal fits have kT$\approx$4 keV, the Raymond-Smith iron abundance is $0.4^{+0.7}_{-0.3}$ Solar, the power-law fit has $\alpha$=1.6$\pm$0.1, and all fits have $N_H$ consistent with the Galactic column. The source is centered on M32 to an accuracy of 9$''$, and unresolved at 27$''$ FWHM ($\sim$90 pc). M32 is x-ray variable by a factor of 3--5 on timescales of a decade down to minutes, with evidence for a possible period of $\sim$1.3 days. There are two plausible interpretations for these results: 1) Emission due to low-mass x-ray binaries; 2) Emission due to accretion onto a massive central black hole. Both of these possibilities are supported by arguments based on previous studies of M32 and other old stellar systems; the {\it ROSAT} PSPC data do not allow us to unambiguously choose between them. Observations with the {\it ROSAT} HRI and with {\it ASCA} are required to determine which of these two very different physical models is correct.Comment: 9 pages, 5 PostScript figures, uses AASTeX style files, Accepted for publication in Astrophysical Journal Letter

The Boundary Cosmological Constant in Stable 2D Quantum Gravity

We study further the r\^ole of the boundary operator \O_B for macroscopic loop length in the stable definition of 2D quantum gravity provided by the $[{\tilde P},Q]=Q$ formulation. The KdV flows are supplemented by an additional flow with respect to the boundary cosmological constant $\sigma$. We numerically study these flows for the $m=1$, $2$ and $3$ models, solving for the string susceptibility in the presence of \O_B for arbitrary coupling $\sigma$. The spectrum of the Hamiltonian of the loop quantum mechanics is continuous and bounded from below by $\sigma$. For large positive $\sigma$, the theory is dominated by the `universal' $m=0$ topological phase present only in the $[{\tilde P},Q]=Q$ formulation. For large negative $\sigma$, the non--perturbative physics approaches that of the $[P,Q]=1$ definition, although there is no path to the unstable solutions of the $[P,Q]=1$ $m$-even models.Comment: (Plain Tex, 11pp, 4 figures available on request) SHEP 91/92-2