Historia vegetal y regímenes de fuego recientes de la turbera costera de Chepu, Isla Grande de Chiloé, Chile

The reconstruction of vegetation through pollen analysis and the fire regimes inferred from charcoal particles are of greatimportance to the study of past climatic phenomena such as the Little Ice Age and the Medieval Warm Period. The aimof this study was to reconstruct the vegetational history of the “Chepu” anthropic peat bog, located on the Great Islandof Chiloé in the Los Lagos Region of Chile, of the last millennium through palynological analysis and a high-resolutionanalysis of macroscopic charcoal particles. This was done doing a stratigraphic boring in the center of the bog to conductthe pollen analysis, obtain dating and quantify the macroscopic charcoal particles. The age model was obtained from threeradiometric datings and PB210 using the program MCAge. The results indicate that the fire patterns have been mainlycontingent upon the prevailing climatic conditions in the area, with consistency being observed in most cases betweenlocal and extralocal fire events in the study area. This fire regime has influenced the abundance of species, indicating adecrease of the arboreal component in periods of fire activity. Changes in the vegetation and fire activity are observedthrough the pollen diagram of the last 2,000 years, associated mainly with variations in precipitation and likely with humanactivity during the 20th century, respectively. Between 1960 and 1961 cal. AD in the profile, a change was observed in thecomposition and abundance of plant taxa associated with the megathrust earthquake in Chile in 1960. The data contributedby this profile are still insufficient to establish the extralocal climatic influence of events such as the Little Ice Age or theMedieval Warm Period on Chiloé, but certain tendencies are observed.La reconstrucción de la vegetación a través del análisis polínico y los regímenes de incendio inferidos a partir de partículasde carbón son de gran importancia para el estudio de fenómenos climáticos pasados, tales como la Pequeña Edad de Hieloy el Periodo Cálido Medieval. El objetivo de este estudio es reconstruir la historia vegetacional de la turbera “Chepu”,de origen antrópico, ubicada en la Isla Grande de Chiloé, Región de Los Lagos, Chile, del último milenio, a través delanálisis palinológico y del análisis de alta resolución de partículas de carbón macroscópico. Para esto se realizó un sondajeestratigráfico en el centro de la turbera con el fin de proceder al análisis de polen, obtener dataciones y cuantificar laspartículas de carbón macroscópicas. El modelo de edad se obtuvo a partir de tres dataciones radiométricas y PB210 utilizandoel programa MCAge. Los resultados obtenidos señalan que los patrones de fuego han estado supeditados principalmentea las condiciones climáticas reinantes en el área, observándose en la mayoría de los casos concordancia entre eventos defuego locales y extralocales en la zona en estudio. Este régimen de fuego tuvo influencia sobre la abundancia de especies,denotándose una disminución del componente arbóreo en períodos de actividad de fuego. Se observan a través del diagramapolínico cambios en la vegetación y en la actividad de fuego durante los últimos 2.000 años, asociados principalmente avariaciones en las precipitaciones y a la probable acción del hombre durante el siglo XX, respectivamente. Entre 1960 y1961 años cal. AD se observa en el perfil un cambio en la composición y abundancia de los taxa vegetales, asociado alevento del megaterremoto de 1960, en Chile. Los datos aportados por este perfil son aún insuficientes para establecer lainfluencia climática extralocal de eventos tales como la Pequeña Edad de Hielo o el Período Cálido Medieval, en Chiloé;aunque se observan ciertas tendencias

Targeting the CXCR4 pathway using a novel anti-CXCR4 IgG1 antibody (PF-06747143) in chronic lymphocytic leukemia.

BackgroundThe CXCR4-CXCL12 axis plays an important role in the chronic lymphocytic leukemia (CLL)-microenvironment interaction. Overexpression of CXCR4 has been reported in different hematological malignancies including CLL. Binding of the pro-survival chemokine CXCL12 with its cognate receptor CXCR4 induces cell migration. CXCL12/CXCR4 signaling axis promotes cell survival and proliferation and may contribute to the tropism of leukemia cells towards lymphoid tissues and bone marrow. Therefore, we hypothesized that targeting CXCR4 with an IgG1 antibody, PF-06747143, may constitute an effective therapeutic approach for CLL.MethodsPatient-derived primary CLL-B cells were assessed for cytotoxicity in an in vitro model of CLL microenvironment. PF-06747143 was analyzed for cell death induction and for its potential to interfere with the chemokine CXCL12-induced mechanisms, including migration and F-actin polymerization. PF-06747143 in vivo efficacy was determined in a CLL murine xenograft tumor model.ResultsPF-06747143, a novel-humanized IgG1 CXCR4 antagonist antibody, induced cell death of patient-derived primary CLL-B cells, in presence or absence of stromal cells. Moreover, cell death induction by the antibody was independent of CLL high-risk prognostic markers. The cell death mechanism was dependent on CXCR4 expression, required antibody bivalency, involved reactive oxygen species production, and did not require caspase activation, all characteristics reminiscent of programmed cell death (PCD). PF-06747143 also induced potent B-CLL cytotoxicity via Fc-driven antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity activity (CDC). PF-06747143 had significant combinatorial effect with standard of care (SOC) agents in B-CLL treatment, including rituximab, fludarabine (F-ara-A), ibrutinib, and bendamustine. In a CLL xenograft model, PF-06747143 decreased tumor burden and improved survival as a monotherapy, and in combination with bendamustine.ConclusionsWe show evidence that PF-06747143 has biological activity in CLL primary cells, supporting a rationale for evaluation of PF-06747143 for the treatment of CLL patients

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Evaluation of Microorganisms Cultured from Injured and Repressed Tissue Regeneration Sites in Endangered Giant Aquatic Ozark Hellbender Salamanders

Investigation into the causes underlying the rapid, global amphibian decline provides critical insight into the effects of changing ecosystems. Hypothesized and confirmed links between amphibian declines, disease, and environmental changes are increasingly represented in published literature. However, there are few long-term amphibian studies that include data on population size, abnormality/injury rates, disease, and habitat variables to adequately assess changes through time. We cultured and identified microorganisms isolated from abnormal/injured and repressed tissue regeneration sites of the endangered Ozark Hellbender, Cryptobranchus alleganiensis bishopi, to discover potential causative agents responsible for their significant decline in health and population. This organism and our study site were chosen because the population and habitat of C. a. bishopi have been intensively studied from 1969–2009, and the abnormality/injury rate and apparent lack of regeneration were established. Although many bacterial and fungal isolates recovered were common environmental organisms, several opportunistic pathogens were identified in association with only the injured tissues of C.a. bishopi. Bacterial isolates included Aeromonas hydrophila, a known amphibian pathogen, Granulicetella adiacens, Gordonai terrae, Stenotrophomonas maltophilia, Aerococcus viridans, Streptococcus pneumoniae and a variety of Pseudomonads, including Pseudomonas aeruginosa, P. stutzeri, and P. alcaligenes. Fungal isolates included species in the genera Penicillium, Acremonium, Cladosporium, Curvularia, Fusarium, Streptomycetes, and the Class Hyphomycetes. Many of the opportunistic pathogens identified are known to form biofilms. Lack of isolation of the same organism from all wounds suggests that the etiological agent responsible for the damage to C. a. bishopi may not be a single organism. To our knowledge, this is the first study to profile the external microbial consortia cultured from a Cryptobranchid salamander. The incidence of abnormalities/injury and retarded regeneration in C. a. bishopi may have many contributing factors including disease and habitat degradation. Results from this study may provide insight into other amphibian population declines