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• 1
Article
In: Biotropica, January 2016, Vol.48(1), pp.34-46
Description: Over the past three decades, many small‐scale floristic studies of white‐sand forests across the Amazon basin have been published. Nonetheless, a basin‐wide description of both taxonomic and phylogenetic alpha and beta diversity at regional scales has never been achieved. We present a complete floristic analysis of white‐sand forests across the Amazon basin including both taxonomic and phylogenetic diversity. We found strong regional differences in the signal of phylogenetic community structure with both overall and regional Net Relatedness Index and Nearest Taxon Index values found to be significantly positive leading to a pattern of phylogenetic clustering. Additionally, we found high taxonomic dissimilarity but low phylogenetic dissimilarity in pairwise community comparisons. These results suggest that recent diversification has played an important role in the assembly of white‐sand forests causing geographic neo‐endemism patterns at the regional scale. En las últimas tres décadas han sido publicados una serie de estudios florísticos acerca de los bosques Amazónicos sobre arenas blancas que han sido enfocados a escalas espaciales locales. Sin embargo, no ha sido posible obtener una descripción de los patrones de diversidad alfa y beta taxonómica y filogenética a escala de la cuenca Amazónica. Aquí presentamos un análisis florístico completo de los bosques Amazónicos sobre arenas que incluye información sobre diversidad taxonómica y filogenética. Encontramos una fuerte señal en la estructura filogenética de estas comunidades tanto a escala regional como de la cuenca Amazónica en su conjunto, valores significativamente positivos del Índice Neto de Relacionamiento Filogenético (Net Relatedness Index) asi como del Índice del Taxón más Cercano (Nearest Taxon Index) indican que estas comunidades están estructuradas por linajes cercanamente relacionados desde el punto de vista filogenético. Además, encontramos una alta disimilitud taxonómica pero baja disimilitud filogenética cuando comparamos pares de comunidades en relación a la distancia geográfica donde estas se localiza. En conjunto estos resultados sugieren que eventos de diversificación han ocurrido recientemente en la historia geológica de estos bosques y han jugado un papel importante en el ensamblaje de los bosques sobre arenas blancas que a su vez a ha determinado patrones de neo‐endemismo geográfico a escala regional.
Keywords: Amazon ; Neo‐Endemism ; Phylogenetic Beta Diversity ; Recent Diversification ; White Sands
ISSN: 0006-3606
E-ISSN: 1744-7429
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• 2
Article
Language: English
In: Breast Cancer Research and Treatment, 2009, Vol.116(2), pp.273-279
Description: Triple-negative breast cancers do not express receptors for estrogen or progesterone and do not overexpress HER2. These tumors have an unfavorable prognosis and at present chemotherapy is the only treatment option. Because the antagonists of growth hormone-releasing hormone (GHRH) have been shown to inhibit growth of a variety of cancers by endocrine and paracrine/autocrine mechanisms, we evaluated the expression of GHRH receptors in human specimens of triple-negative breast cancers and the response to GHRH by in vitro models. In samples of triple-negative breast cancers we found mRNA expression for the GHRH receptor and its functional splice variant SV1 in 25 and 70% of the cases, respectively and for GHRH in 80% of the samples. Immunoreaction of SV1 was detected in the human triple-negative breast cancer cell line HCC1806 while HCC1937 was negative. The growth of HCC1806 was stimulated by GHRH(1-44)NH 2 and inhibited by GHRH antagonist MZ-J-7-118. In addition, in HCC1806 MAP-kinases ERK-1/2 were activated by GHRH. Our findings suggest the existence of an autocrine loop consisting of GHRH and GHRH receptors in triple-negative breast cancers. Our in vitro studies demonstrate that targeting the GHRH receptor may be a therapeutic option which should be evaluated in studies in vivo.
Keywords: Triple-negative ; Breast cancer ; Growth hormone-releasing hormone ; GHRH antagonist ; MAP-kinase
ISSN: 0167-6806
E-ISSN: 1573-7217
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• 3
Article
Language: English
In: Sci Rep, 2018, Vol.8(1), pp.1003-1003
Description: Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider this limitation, especially for large biodiversity assessments projects, when they are automatically generated without subsequent checking. Our pipeline provides a conservative estimate of a species’ area of occupancy, within an area slightly larger than its extent of occurrence, compatible to e.g. IUCN red list assessments.
Keywords: Article;
ISSN: 2045-2322
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• 4
Article
Language: English
In: Science advances, November 2015, Vol.1(10), pp.e1500936
Description: Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world's 〉40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century.
Keywords: Amazonia ; Conservation ; Deforestation ; Indigenous Areas ; Protected Areas ; Tree Species
ISSN: 2375-2548
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• 5
Article
In: Phys. Rev. D 93, 122005 (2016)
Description: 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 DOI
Keywords: Astrophysics - High Energy Astrophysical Phenomena ; Astrophysics - Instrumentation And Methods For Astrophysics
ISSN: 24700010
E-ISSN: 24700029
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• 6
Article
In: Phys. Rev. D 91, 092008 (2015)
Description: Neutrinos in the cosmic ray flux with energies near 1 EeV and above are detectable with the Surface Detector array of the Pierre Auger Observatory. We report here on searches through Auger data from 1 January 2004 until 20 June 2013. No neutrino candidates were found, yielding a limit to the diffuse flux of ultra-high energy neutrinos that challenges the Waxman-Bahcall bound predictions. Neutrino identification is attempted using the broad time-structure of the signals expected in the SD stations, and is efficiently done for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for "Earth-skimming" neutrino interactions in the case of tau neutrinos. In this paper the searches for downward-going neutrinos in the zenith angle bins $60^\circ-75^\circ$ and $75^\circ-90^\circ$ as well as for upward-going neutrinos, are combined to give a single limit. The $90\%$ C.L. single-flavor limit to the diffuse flux of ultra-high energy neutrinos with an $E^{-2}$ spectrum in the energy range $1.0 \times 10^{17}$ eV - $2.5 \times 10^{19}$ eV is $E_\nu^2 dN_\nu/dE_\nu 〈 6.4 \times 10^{-9}~ {\rm GeV~ cm^{-2}~ s^{-1}~ sr^{-1}}$. Comment: Replaced with published version. Added journal reference and DOI
Keywords: Astrophysics - High Energy Astrophysical Phenomena
ISSN: 15507998
E-ISSN: 15502368
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• 7
Article
In: JCAP 08 (2015) 049
Description: 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 DOI
Keywords: Astrophysics - High Energy Astrophysical Phenomena ; High Energy Physics - Experiment
ISSN: 14757516
E-ISSN: 14757516
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• 8
Article
In: Phys. Rev. Lett. 116, 241101 (2016)
Description: 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 files
Keywords: Astrophysics - High Energy Astrophysical Phenomena ; Astrophysics - Instrumentation And Methods For Astrophysics ; High Energy Physics - Experiment
ISSN: 00319007
E-ISSN: 10797114
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• 9
Article
Language: English
In: Journal of High Energy Physics, 2012, Vol.2012(11), pp.1-31
Description: The ALICE experiment at the LHC has studied J/ ψ production at mid-rapidity in pp collisions at $\sqrt{s}=7$ TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L int = 5 . 6 nb −1 . The fraction of J/ ψ from the decay of long-lived beauty hadrons was determined for J/ ψ candidates with transverse momentum p t 〉 1 . 3 GeV/ c and rapidity | y | 〈 0 . 9. The cross section for prompt J/ ψ mesons, i.e. directly produced J/ ψ and prompt decays of heavier charmonium states such as the ψ (2S) and χ c resonances, is σ prompt J/ ψ ( p t 〉 1 . 3 GeV /c, | y | 〈 0 . 9) = 8 . 3 ± 0 . 8 (stat . ) ± 1 . 1 (syst . ) $_{-1.4}^{+1.5 }$ (syst . pol . ) μ b. The cross section for the production of b-hadrons decaying to J/ ψ with p t 〉 1 . 3 GeV/ c and | y | 〈 0 . 9 is ${\sigma_{{{J \left/ {{\psi \leftarrow {{\mathrm{h}}_{\mathrm{B}}}}} \right.}}}}$ ( p t 〉 1.3 GeV/ c , | y | 〈 0.9) = 1.46 ± 0.38 (stat.) $_{-0.32}^{+0.26 }$ (syst.) μ b. The results are compared to QCD model predictions. The shape of the p t and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the $\mathrm{b}\overline{\mathrm{b}}$ pair total cross section and d σ/ d y at mid-rapidity.
Keywords: Hadron-Hadron Scattering
E-ISSN: 1029-8479
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• 10
Article
Language: English
In: Journal of High Energy Physics, 2012, Vol.2012(7), pp.1-43
Description: We present measurements of Underlying Event observables in pp collisions at $\sqrt {s} = 0.9$ and 7TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p T,LT in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p T thresholds: 0.15, 0.5 and 1.0 GeV /c . In the Transverse region we observe an increase in the multiplicity of a factor 2–3 between the lower and higher collision energies, depending on the track p T threshold considered. Data are compared to P ythia 6.4, P ythia 8.1 and P hojet . On average, all models considered underestimate the multiplicity and summed p T in the Transverse region by about 10–30%.
Keywords: Hadron-Hadron Scattering
E-ISSN: 1029-8479
Source: Springer Science & Business Media B.V.
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