QCD and strongly coupled gauge theories : challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

Defining the tipping point. A complex cellular life/death balance in corals in response to stress

Apoptotic cell death has been implicated in coral bleaching but the molecules involved and the mechanisms by which apoptosis is regulated are only now being identified. In contrast the mechanisms underlying apoptosis in higher animals are relatively well understood. To better understand the response of corals to thermal stress, the expression of coral homologs of six key regulators of apoptosis was studied in Acropora aspera under conditions simulating those of a mass bleaching event. Significant changes in expression were detected between the daily minimum and maximum temperatures. Maximum daily temperatures from as low as 3°C below the bleaching threshold resulted in significant changes in both pro- and anti-apoptotic gene expression. The results suggest that the control of apoptosis is highly complex in this eukaryote-eukaryote endosymbiosis and that apoptotic cell death cascades potentially play key roles tipping the cellular life/death balance during environmental stress prior to the onset of coral bleaching

On the Origin of Slow Changes in Ionic Conductivity of Model Block Copolymer Electrolyte Membranes in Contact with Humid Air

Proton conductivity (sigma) and degree of hydration (lambda) of poly(styrenesullonate-methylbutylene) (PSS-PMB) block copolymers in contact with humid air were studied as a function of temperature under high-humidity conditions (relative humidity between 90 and 98%). The volume fraction of the hydrophilic PSS block in the dry state was 0.27 +/- 0.01 in all of the samples, and the size of the hydrophilic channels was varied by varying the overall molecular weight of the samples. All of the samples have a lamellar structure in the dry state. The water uptake data were unremarkable, and a degree of hydration of 14 +/- 2 H2O molecules per sulfonic acid group was obtained, regardless of temperature, thermal history, and hydrophilic channel size. In contrast, measured values of sigma were highly dependent on thermal history and sample molecular weight. Equilibrated values of sigma, obtained only after heating the samples to 90 degrees C for 48 h, were significantly lower than those obtained after initially hydrating the polymer films during the heating runs. In addition, the low molecular weight samples were more sensitive to thermal history than the high molecular weight samples. Small-angle neutron scattering and transmission electron microscopy studies on the humidified samples revealed that the low molecular weight samples undergo a transition to hexagonally perforated lamellae upon hydration while the highest molecular weight sample did not. We speculate that the slow changes in sigma are due to the formation of less connected ion transporting channels or ionic clusters that impede ion motion. Equilibrated ionic conductivities increase as the hydrophilic channel size decreases,X112829sciescopu