Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Data from: Acoustic cues from within the egg do not heighten depredation risk to shorebird clutches

Egg predators use an array of olfactory and visual cues to locate eggs. Precocial avian embryos within eggs can produce vocalizations for a period prior to hatching, which may be audible to predators. Here, we investigated, under field conditions, the embryonic vocalizations emitted from eggs of a shorebird species, the Red-capped Plover Charadrius ruficapillus. We characterize the acoustic properties of the vocalizations and the circumstances under which they are emitted, then test whether such vocalizations are used as an acoustic cue by predators to locate eggs. Embryonic vocalizations typically occurred between 0 and 5 days before hatching (henceforth the “vocalization period”). Within the vocalization period, the maximum acoustic frequency (kHz) of vocalizations increased with egg age (perhaps as a consequence of embryonic development) and the minimum acoustic frequency (kHz) increased with ground temperature (perhaps as mode of communication with parents regarding thermal needs). An artificial nest experiment compared the survival of nests with and without acoustic cues (prerecorded embryonic vocalizations played continuously from the nest). Corvids were the major egg predator (accounting for 76% of cases of artificial nest predation). However, the presence of vocalizations did not affect the time taken for predators to locate and depredate eggs. Our results suggest that embryonic vocalizations are important signals that may aid in communication with parents but that they do not increase predation rates. Further research involving a greater diversity of predators (e.g., acoustic predators) is required to examine whether vocalizations from the egg incur costs under other predator regimes

HAZID, a computer aid for hazard identification:3. The fluid model and consequence evaluation systems

The hazard and operability, or HAZOP, study is a prime method for the identification of hazards on process plants. This is the third in a series of papers which describes progress in the emulation of hazard identification in the style of HAZOP. The work reported is embodied in a computer aid for hazard identification, or HAZOP emulator, HAZID. The HAZID code is one of a suite of codes developed as part of the STOPHAZ project. The present paper describes the fluid model system and the evaluation of consequences.Companion papers describe: an overview of HAZID, with an account of HAZOP and HAZOP emulation, and of the issues underlying it; the unit model system; the evaluation and improvement of HAZID using case studies and other methods; some development topics. Conclusions from the work are given in the final paper

HAZID, a computer aid for hazard identification:1. The STOPHAZ package and the HAZID code: an overview, the issues and the structure

The hazard and operability, or HAZOP, study is a prime method for the identification of hazards on process plants. This is the first in a series of papers which describes progress in the emulation of hazard identification in the style of HAZOP. The work reported is embodied in a computer aid for hazard identification, or HAZOP emulator, HAZID. The HAZID code is one of a suite of codes developed as part of the STOPHAZ project. The present paper gives an overview of HAZID, with an account of HAZOP and HAZOP emulation, and of the issues underlying it.Companion papers describe the unit model system, the fluid model system and the evaluation of consequences, the evaluation and improvement of HAZID using case studies and other methods, and some development topics. Conclusions from the work are given in the final paper