Quantifying Fire Behavior Versus Societal Benefits of Southern California Shrublands and Grasslands

Urban sprawl in southern California perpetually threatens native shrublands and grasslands, which intrinsically provide both biophysical and socioeconomic benefits to society. However, these vegetation types are simultaneously prone to high-intensity wildfires that lead to enormous damage to human interests. After the southern California firestorms of October 2003, new regulations were adopted that increased the mandatory vegetation clearance around structures in order to reduce fire risk, which may significantly impact the positive benefits that grasslands and shrublands provide. To address this apparent conflict, we investigated the tradeoffs between societal benefits derived from major shrubland, grassland, and woodland vegetation types in southern California versus the potential fire behavior associated with each vegetation type. Two state-of-the-art, geographic information system–based software packages were utilized in the analysis, which focused on San Diego County, California. For each of the most common grassland, shrubland, and woodland vegetation communities in the area, FARSITE was utilized to assess potential fire behavior under average and extreme weather conditions. The most extreme fire behavior was found in nonnative grasslands and scrub oak chaparral communities and least extreme in coast live oak (Quercus agrifolia) communities. Under Santa Ana wind conditions, simulated fires in almost all vegetation types burned over 3 km into a developed area in removal, carbon sequestration, and stormwater retention for each of the vegetation types, but was found to be largely ineffective because it calculated no measurable benefits for any non-tree vegetation types. To ensure sustainable neighborhoods in the wildland–urban interface, diverse stakeholders must create collaborative management plans that simultaneously reduce fire risk and maximize societal benefits

Postfire Succession and Disturbance Interactions on an Intermountain Subalpine Spruce-Fir Forest

Four general post fire successional pathways leading to a climax Engelmann spruce (Picea engelmannii Parry) subalpine fire (Abies lasiocarpa [Hook] Nutt.) forest operate on the T.W. Daniel Experimental Forest in northern Utah. Depending on the successional pathway followed, reestablishment of the prefire climax will take 200 to 400 years or more due to a rarity of extreme burning conditions. During the long period between catastrophic stand-replacing fires, a variety of other natural disturbances contribute to the varying structure and composition of vegetation and the fuel mosaic in intermountain subalpine spruce-fir forests. Disturbances may range from chronic and small scale to acute and catastrophic, resulting in a broad range of vegetative responses. In addition to crown fires, other major abiotic disturbances (I.E. landslides, mudflows, severe soil erosion, snow avalanche) and biotic disturbances (i.e. disease and insect outbreaks) control the availability of sites for the initiation of new stands of accelerated growth of understory plants and subcanopy trees. Understanding the role of natural disturbance in forest ecosystems is key to managing long-return interval fire regimes. This paper explains how the disturbance regime operating in a given landscape influences vegetative dynamics and fuel mosaics and how the state of the vegetation in turn influences these natural disturbance agents. Managers must recognize biotic and abiotic agents of disturbance and their interactions to fully understand fire regimes and the effects of fire suppression and prescribed fire

Benzoflavone activators of the cystic fibrosis transmembrane conductance regulator: towards a pharmacophore model for the nucleotide-binding domain

Our previous screen of flavones and related heterocycles for the ability to activate the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel indicated that UCCF-029, a 7,8-benzoflavone, was a potent activator. In the present study, we describe the synthesis and evaluation, using cell-based assays, of a series of benzoflavone analogues to examine structure-activity relationships and to identify compounds having greater potency for activation of both wild type CFTR and a mutant CFTR (G551D-CFTR) that causes cystic fibrosis in some human subjects. Using UCCF-029 as a structural guide, a panel of 77 flavonoid analogues was prepared. Analysis of the panel in FRT cells indicated that benzannulation of the flavone A-ring at the 7,8-position greatly improved compound activity and potency for several flavonoids. Incorporation of a B-ring pyridyl nitrogen either at the 3- or 4-position also elevated CFTR activity, but the influence of this structural modification was not as uniform as the influence of benzannulation. The most potent new analogue, UCCF-339, activated wild-type CFTR with a K(d) of 1.7 microM, which is more active than the previous most potent flavonoid activator of CFTR, apigenin. Several compounds in the benzoflavone panel also activated G551D-CFTR, but none were as active as apigenin. Pharmacophore modeling suggests a common binding mode for the flavones and other known CFTR activators at one of the nucleotide-binding sites, allowing for the rational development of more potent flavone analogues

Search for pair production of excited top quarks in the lepton+jets final state

A search is performed for pair-produced spin-3/2 excited top quarks (t* t*-bar), each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp collisions at a center-of-mass energy of sqrt(s)=8 TeV, selecting events that have a single isolated muon or electron, an imbalance in transverse momentum, and at least six jets, of which one must be compatible with originating from the fragmentation of a b quark. The data, corresponding to an integrated luminosity of 19.5 inverse femtobarns, show no significant excess over standard model predictions, and provide a lower limit of 803 GeV at 95% confidence on the mass of the spin-3/2 t* quark in an extension of the Randall-Sundrum model, assuming a 100% branching fraction of its decay into a top quark and a gluon. This is the first search for a spin-3/2 excited top quark performed at the LHC

WMAP, neitrino degeneracy and non-Gaussianity contraints on, isocurvature perturbations in the curvaton model of inflation

In the curvaton model of inflation, where a second scalar field, the “curvaton,” is responsible for the observed inhomogeneity, a nonzero neutrino degeneracy may lead to a characteristic pattern of isocurvature perturbations in the neutrino, cold dark matter and baryon components. We find that the current data can only place upper limits on the level of isocurvature perturbations. These can be translated into upper limits on the neutrino degeneracy parameter. In the case that lepton number is created before curvaton decay, we find that the limit on the neutrino degeneracy parameter is comparable with that obtained from big-bang nucleosynthesis. For the case that lepton number is created by curvaton decay we find that the absolute value of the non-Gaussianity parameter, |fnl|, must be less than 10 (95% confidence interval)