1,899 research outputs found

    What children know about the source of their knowledge without reporting it as the source

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    We argue that, amongst 3- to 5- year-olds, failure to report the source of knowledge recently acquired in answer to “How do you know…?” is due to a specific failure to make a causal inference, in line with source monitoring theory but not fuzzy trace theory. In three Experiments, children (N = 37; 30; 59) identified a hidden toy by seeing, feeling, or by being told, having had two modes of access on each trial, one informative (e.g. seeing a toy identified by colour) and the other uninformative (e.g. being told the toy’s colour by the Experimenter who had only felt it). Children who answered the know question wrongly nevertheless reported accurately who saw and who felt the toy, and what the well-informed player had said. They also realised when the Experimenter’s uninformative access implied their own knowledge was unreliable, suggesting precocious working understanding of knowledge sources

    Relationships between CO2 soil degassing and regional/local fault systems in the Kiejo-Mbaka geothermal prospect (Tanzania)

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    The Kiejo-Mbaka geothermal prospect in the Mbeya region of SW Tanzania was surveyed for geothermal exploration in a recent study co-financed by the Ministry for Foreign Affairs in Iceland and by the Nordic Development Fund (NDF) and implemented by the Tanzania Geothermal Development Company Limited (TGDC). A multidisciplinary approach was adopted, including geological, geochemical and geophysical surveys. The prospect falls within the southern sector of the Rungwe Volcanic Province (RVP), which is situated at the triple junction of the Rukwa, Usangu and Karonga basins of the East Africa Rift System. Recent volcanism is concentrated in the northern sector of the RVP, whereas recent eruptions were sustained by small magma batches derived from deep sources in the prospect area. Local stratigraphy is mainly characterized by Pre-Cambrian rocks of the metamorphic-intrusive complex covered by Pleistocene volcanic products (basalts and ignimbrites) with a thickness never exceeding 200 m. Several fault systems are present, among which the most important ones trend NW-SE and N-S. The main tectonic feature is the NW-SE-trending Mbaka fault, which controls the local emergence of hot waters at Ilwalilo and Kilambo-Kajala (maximum discharge temperature of 64\ub0C), delimits to the W the Mbaka ridge, and is associated with a series of parallel structures extending in the plain. Both the gravimetric and the electromagnetic surveys concur in identifying the existence of a block corresponding to the above mentioned Mbaka ridge and characterized by a pronounced positive Bouguer anomaly and by high resistivity, due to the proximity of basement rocks. At Kiejo, Ikama, and Lufundo there are gas vents emitting CO2-rich gases, which are captured by drilled wells in the first two sites. Since the Kiejo-Mbaka prospect is classified as an extensional domain, in which flow-paths of geothermal fluids are fault-controlled, part of the geochemical survey was addressed to identify and define the relationships between fluid flow and structures at local scale, in selected hydrothermal areas including Kilambo-Kajala, Ilwalilo and Kiejo. Taking into account the regional fault distribution and preliminary results obtained during the field surveys, also others areas were included in the investigation (i.e. Lufundo, Itende and Kikusya). A total of 598 soil CO2 flux and temperature measurements (~1 m depth) were carried out. Total output was estimated and isoflux maps were elaborated for each investigated sector. In general, CO2 fluxes appear to be controlled by NW-SE and N-S trending faults and fractures. The former prevails at Kiejo, Kilambo-Kajala and Ilwalilo, which is not surprising for Kilambo-Kajala and Ilwalilo, since the hot springs are positioned along the Mbaka fault. In contrast, the N-S trend dominates at Lufundo

    Linear entropy in quantum phase space

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    We calculate the quantum Renyi entropy in a phase space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner product divergences. The preferred method is to use generalized Gaussian phase space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.Comment: 12 pages, 3 figures. To be published in Phys. Rev.

    Bayesian detection of unmodeled bursts of gravitational waves

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    The data analysis problem of coherently searching for unmodeled gravitational-wave bursts in the data generated by a global network of gravitational-wave observatories has been at the center of research for almost two decades. As data from these detectors is starting to be analyzed, a renewed interest in this problem has been sparked. A Bayesian approach to the problem of coherently searching for gravitational wave bursts with a network of ground-based interferometers is here presented. We demonstrate how to systematically incorporate prior information on the burst signal and its source into the analysis. This information may range from the very minimal, such as best-guess durations, bandwidths, or polarization content, to complete prior knowledge of the signal waveforms and the distribution of sources through spacetime. We show that this comprehensive Bayesian formulation contains several previously proposed detection statistics as special limiting cases, and demonstrate that it outperforms them.Comment: 18 pages, 3 figures, revisions based on referee comment

    Draft genome sequences of Pseudomonas fluorescens strains SF39a and SF4c, potential plant growth promotion and biocontrol agents

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    Pseudomonas fluorescens SF4c and SF39a, strains isolated from wheat rhizosphere, have potential applications in plant growth promotion and biocontrol of fungal diseases of crop plants. We report the draft genome sequences of SF4c and SF39a with estimated sizes of 6.5 Mb and 5.9 Mb, respectively.Fil: Ly, Lindsey K.. University of Massachussets; Estados UnidosFil: Underwood, Grace E.. University of Massachussets; Estados UnidosFil: McCully, Lucy M.. University of Massachussets; Estados UnidosFil: Bitzer, Adam S.. University of Massachussets; Estados UnidosFil: Godino, Agustina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba; Argentina. Universidad Nacional de RĂ­o Cuarto. Facultad de Ciencias Exactas, FisicoquĂ­micas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Bucci, Vanni. University of Massachussets; Estados UnidosFil: Brigham, Christopher J.. University of Massachussets; Estados UnidosFil: Principe, Analia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba; Argentina. Universidad Nacional de RĂ­o Cuarto. Facultad de Ciencias Exactas, FisicoquĂ­micas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Fischer, Sonia Elizabeth. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba; Argentina. Universidad Nacional de RĂ­o Cuarto. Facultad de Ciencias Exactas, FisicoquĂ­micas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Silby, Mark W.. University of Massachussets; Estados Unido

    A new activity phase of the blazar 3C 454.3. Multifrequency observations by the WEBT and XMM-Newton in 2007-2008

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    We present and analyse the WEBT multifrequency observations of 3C 454.3 in the 2007-2008 observing season, including XMM-Newton observations and near-IR spectroscopic monitoring, and compare the recent emission behaviour with the past one. In the optical band we observed a multi-peak outburst in July-August 2007, and other faster events in November 2007 - February 2008. During these outburst phases, several episodes of intranight variability were detected. A mm outburst was observed starting from mid 2007, whose rising phase was contemporaneous to the optical brightening. A slower flux increase also affected the higher radio frequencies, the flux enhancement disappearing below 8 GHz. The analysis of the optical-radio correlation and time delays, as well as the behaviour of the mm light curve, confirm our previous predictions, suggesting that changes in the jet orientation likely occurred in the last few years. The historical multiwavelength behaviour indicates that a significant variation in the viewing angle may have happened around year 2000. Colour analysis reveals a complex spectral behaviour, which is due to the interplay of different emission components. All the near-IR spectra show a prominent Halpha emission line, whose flux appears nearly constant. The analysis of the XMM-Newton data indicates a correlation between the UV excess and the soft-X-ray excess, which may represent the head and the tail of the big blue bump, respectively. The X-ray flux correlates with the optical flux, suggesting that in the inverse-Compton process either the seed photons are synchrotron photons at IR-optical frequencies or the relativistic electrons are those that produce the optical synchrotron emission. The X-ray radiation would thus be produced in the jet region from where the IR-optical emission comes.Comment: 10 pages, 12 figures (7 included in the text, 5 in GIF format), accepted for publication in A&

    Cytoplasmic PML promotes TGF-β-associated epithelial–mesenchymal transition and invasion in prostate cancer

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    Epithelial–mesenchymal transition (EMT) is a key event that is involved in the invasion and dissemination of cancer cells. Although typically considered as having tumour-suppressive properties, transforming growth factor (TGF)-β signalling is altered during cancer and has been associated with the invasion of cancer cells and metastasis. In this study, we report a previously unknown role for the cytoplasmic promyelocytic leukaemia (cPML) tumour suppressor in TGF-β signalling-induced regulation of prostate cancer-associated EMT and invasion. We demonstrate that cPML promotes a mesenchymal phenotype and increases the invasiveness of prostate cancer cells. This event is associated with activation of TGF-β canonical signalling pathway through the induction of Sma and Mad related family 2 and 3 (SMAD2 and SMAD3) phosphorylation. Furthermore, the cytoplasmic localization of promyelocytic leukaemia (PML) is mediated by its nuclear export in a chromosomal maintenance 1 (CRM1)-dependent manner. This was clinically tested in prostate cancer tissue and shown that cytoplasmic PML and CRM1 co-expression correlates with reduced disease-specific survival. In summary, we provide evidence of dysfunctional TGF-β signalling occurring at an early stage in prostate cancer. We show that this disease pathway is mediated by cPML and CRM1 and results in a more aggressive cancer cell phenotype. We propose that the targeting of this pathway could be therapeutically exploited for clinical benefit

    Search for Gravitational Wave Bursts from Soft Gamma Repeaters

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    We present the results of a LIGO search for short-duration gravitational waves (GWs) associated with Soft Gamma Repeater (SGR) bursts. This is the first search sensitive to neutron star f-modes, usually considered the most efficient GW emitting modes. We find no evidence of GWs associated with any SGR burst in a sample consisting of the 27 Dec. 2004 giant flare from SGR 1806-20 and 190 lesser events from SGR 1806-20 and SGR 1900+14 which occurred during the first year of LIGO's fifth science run. GW strain upper limits and model-dependent GW emission energy upper limits are estimated for individual bursts using a variety of simulated waveforms. The unprecedented sensitivity of the detectors allows us to set the most stringent limits on transient GW amplitudes published to date. We find upper limit estimates on the model-dependent isotropic GW emission energies (at a nominal distance of 10 kpc) between 3x10^45 and 9x10^52 erg depending on waveform type, detector antenna factors and noise characteristics at the time of the burst. These upper limits are within the theoretically predicted range of some SGR models.Comment: 6 pages, 1 Postscript figur
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