Effects of fuels/fire risk reduction treatments using hydro-mow or thinning on pinyon-juniper ecosystem components within the wildland-urbaninterface.

Pinyon-juniper woodlands are a dominant vegetation type throughout the Interior West on lands managed by the U.S. Forest Service and the USDI Bureau of Land Management. The woodlands have traditionally been viewed as having a low risk of wildfires because of the lack of a continuous and dense ground cover and low tree stand densities. However, stand densities are often high and are increasing in many areas and wildfires, often resulting in loss of lives and property, will occur under conditions of low humidity, high temperatures and wind speeds, and an ignition source. Woodlands commonly surround or are adjacent to many towns in the region; however, in recent years, people have moved into the woodlands to construct individual homes and housing developments. In this decade, the ecology and fire risk in pinyon-juniper woodlands have changed dramatically because of the continuing drought and the region-wide infestation of the pinyon engraver beetle, Ips confusus, which have resulted in high pinyon mortality, increased fuel loadings, and risks of severe wildfires. Managers are attempting to reduce fire hazards and create defensible spaces in the wildland-urban-interface (W.U.I.). They have commonly used hand thinning-piling-burning prescriptions in the W.U.I. but have recently turned to mechanical mastication to accomplish stand reduction goals, especially where slope and soil surface conditions permit the safe operation of heavy equipment. In most situations the goal is to create a mosaic of open and wooded conditions on the landscape. These has advantages of maintaining wildlife habitats, tree and shrub growth, an esthetic landscape, and increasing herbaceous production while improving fire suppression opportunities and reducing fire hazards. However, managers do not know the consequences of mastication on soil nutrient and microbiological populations and on the residual tree, shrub, and herbaceous vegetation. While the number of research studies of the effects mastication on ecosystem components has increased recently, there still are many questions

Retroviral vector insertion sites associated with dominant hematopoietic clones mark “stemness” pathways

Evidence from model organisms and clinical trials reveals that the random insertion of retrovirus-based vectors in the genome of long-term repopulating hematopoietic cells may increase self-renewal or initiate malignant transformation. Clonal dominance of nonmalignant cells is a particularly interesting phenotype as it may be caused by the dysregulation of genes that affect self-renewal and competitive fitness. We have accumulated 280 retrovirus vector insertion sites (RVISs) from murine long-term studies resulting in benign or malignant clonal dominance. RVISs (22.5%) are located in or near (up to 100 kb [kilobase]) to known proto-oncogenes, 49.6% in signaling genes, and 27.9% in other or unknown genes. The resulting insertional dominance database (IDDb) shows substantial overlaps with the transcriptome of hematopoietic stem/progenitor cells and the retrovirus-tagged cancer gene database (RTCGD). RVISs preferentially marked genes with high expression in hematopoietic stem/progenitor cells, and Gene Ontology revealed an overrepresentation of genes associated with cell-cycle control, apoptosis signaling, and transcriptional regulation, including major “stemness” pathways. The IDDb forms a powerful resource for the identification of genes that stimulate or transform hematopoietic stem/progenitor cells and is an important reference for vector biosafety studies in human gene therapy

Structural basis for a new tetracycline resistance mechanism relying on the TetX monooxygenase.

The flavin-dependent monooxygenase TetX confers resistance to all clinically relevant tetracyclines, including the recently approved, broad-spectrum antibiotic tigecycline (Tygacil®) which is a critical last-ditch defense against multidrug-resistant pathogens. TetX represents the first resistance mechanism against tigecycline, which circumvents both the tet-gene encoded resistances, relying on active efflux of tetracyclines, and ribosomal protection proteins. The alternative enzyme-based mechanism of TetX depends on regioselective hydroxylation of tetracycline antibiotics to 11a-hydroxy-tetracyclines. Here, we report the X-ray crystallographic structure determinations at 2.1Å resolution of native TetX from Bacteroides thetaiotaomicron and its complexes with tetracyclines. Our crystal structures explain the extremely versatile substrate diversity of the enzyme and provide a first step towards the rational design of novel tetracycline derivatives to counter TetX-based resistance prior to emerging clinical observations

Acuerdo 008 (BIS). "Por el cual se adopta la Política Integral para la Prevención y Atención del Consumo de Sustancias Psicoactivas en la Universidad de Córdoba"

Energetic particles are critical components of plasma populations found throughout the universe. In many cases particles are accelerated to relativistic energies and represent a substantial fraction of the total energy of the system, thus requiring extremely efficient acceleration processes. The production of accelerated particles also appears coupled to magnetic field evolution in astrophysical plasmas through the turbulent magnetic fields produced by diffusive shock acceleration. Particle acceleration is thus a key component in helping to understand the origin and evolution of magnetic structures in, e. g. galaxies. The proximity of the Sun and the range of high-resolution diagnostics available within the solar atmosphere offers unique opportunities to study the processes involved in particle acceleration through the use of a combination of remote sensing observations of the radiative signatures of accelerated particles, and of their plasma and magnetic environment. The SPARK concept targets the broad range of energy, spatial and temporal scales over which particle acceleration occurs in the solar atmosphere, in order to determine how and where energetic particles are accelerated. SPARK combines highly complementary imaging and spectroscopic observations of radiation from energetic electrons, protons and ions set in their plasma and magnetic context. The payload comprises focusing-optics X-ray imaging covering the range from 1 to 60 keV; indirect HXR imaging and spectroscopy from 5 to 200 keV, γ-ray spectroscopic imaging with high-resolution LaBr 3 scintillators, and photometry and source localisation at far-infrared wavelengths. The plasma environment of the regions of acceleration and interaction will be probed using soft X-ray imaging of the corona and vector magnetography of the photosphere and chromosphere. SPARK is designed for solar research. However, in addition it will be able to provide exciting new insights into the origin of particle acceleration in other regimes, including terrestrial gamma-ray flashes (TGF), the origin of γ-ray bursts, and the possible existence of axions. © 2011 Springer Science+Business Media B.V