Trawl-induced Damage to Sponges Observed From a Research Submersible

Three experimental trawl paths subjected to a single pass with the trawl in 1996 in about 200 m of water on the eastern Gulf of Alaska continental shelf were revisited in July 1997, 1 year post-trawl. Many large, erect sponges, the taxa impacted most significantly, had been removed or damaged by the trawl. Sponges in the cold, deep water of the Gulf of Alaska were slow to recover from trawling effects. These findings contrast with recovery times for shallow, warmwater sponges and may have fishery management implications for cold-water regions

Congruence lattices of semilattices

The main result of this paper is that the class of congruence lattices of semilattices satisfies no nontrivial lattice identities. It is also shown that the class of subalgebra lattices of semilattices satisfies no nontrivial lattice identities. As a consequence it is shown that if V is a semigroup variety all of whose congruence lattices satisfy some fixed nontrivial lattice identity, then all the members of V are groups with exponent dividing a fixed finite number

Effects of visuospatial tasks on desensitization to emotive memories

Objectives: Vivid and intrusive memories of extreme trauma can disrupt a stepwise approach to imaginal exposure. Concurrent tasks that load the visuo-spatial sketchpad (VSSP) of working memory reduce memory vividness during imaginal exposure. Such tasks may help maintain a progressive exposure protocol while minimizing distress during treatment. The current study tested whether relief of distress from a competing VSSP load during emotive imagery is at the cost of impaired desensitization. Design: This study examined repeated exposure to emotive memories using 18 unselected undergraduates, using a within-subjects design. Method: Participants recalled three positive and three negative self-related memories, and rated the vividness and emotiveness of the image. Participants then received all three conditions (Eye Movements; Visual Noise; Control) in a counterbalanced order. One positive and one negative recollection were used for each condition. They then rated the vividness of the image and their emotional response before proceeding to the next trial. There were 8 trials for each image. At a noninterference session one week later, participants recalled each image, rating its vividness and their emotional response. Results: Consistent with previous research, vividness and distress during imaging were lower during eye movements than in exposure alone, with passive visual interference giving intermediate results. A small reduction in emotional responses a week later was of similar size for the three conditions

XENON10/100 dark matter constraints in comparison with CoGeNT and DAMA: examining the Leff dependence

We consider the compatibility of DAMA/LIBRA, CoGeNT, XENON10 and XENON100 results for spin-independent (SI) dark matter Weakly Interacting Massive Particles (WIMPs), particularly at low masses (~ 10 GeV), assuming a standard dark matter halo. The XENON bounds depend on the scintillation efficiency factor Leff for which there is considerable uncertainty. Thus we consider various extrapolations for Leff at low energy. With the Leff measurements we consider, XENON100 results are found to be insensitive to the low energy extrapolation. We find the strongest bounds are from XENON10, rather than XENON100, due to the lower energy threshold. For reasonable choices of Leff and for the case of SI elastic scattering, XENON10 is incompatible with the DAMA/LIBRA 3$\sigma$ region and severely constrains the 7-12 GeV WIMP mass region of interest published by the CoGeNT collaboration.Comment: 23 pages, 9 figures. Version 2: more careful treatment of XENON10 efficiencies, expanded discussion. A response to arXiv:1006.2031 is found in the Appendi

Chain Inflation in the Landscape: "Bubble Bubble Toil and Trouble"

In the model of Chain Inflation, a sequential chain of coupled scalar fields drives inflation. We consider a multidimensional potential with a large number of bowls, or local minima, separated by energy barriers: inflation takes place as the system tunnels from the highest energy bowl to another bowl of lower energy, and so on until it reaches the zero energy ground state. Such a scenario can be motivated by the many vacua in the stringy landscape, and our model can apply to other multidimensional potentials. The ''graceful exit'' problem of Old Inflation is resolved since reheating is easily achieved at each stage. Coupling between the fields is crucial to the scenario. The model is quite generic and succeeds for natural couplings and parameters. Chain inflation succeeds for a wide variety of energy scales -- for potentials ranging from 10MeV scale inflation to $10^{16}$ GeV scale inflation.Comment: 31 pages, 3 figures, one reference adde