13,454 research outputs found

    Reality-monitoring characteristics in confirmed and doubtful allegations of abuse

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    According to reality-monitoring theory, memories of experienced and imagined events are qualitatively different, and can be distinguished by children from the age of 3. Across three studies, a total of 119 allegations of sexual abuse by younger (aged 3-8) and older (aged 9-16) children were analyzed for developmental differences in the presence of reality-monitoring criteria, which should characterise descriptions of experienced events. Statements were deemed likely or unlikely to be descriptions of actual incidents using independent case information (e.g., medical evidence). Accounts by older children consistently contained more reality-monitoring criteria than those provided by younger children, and age differences were particularly strong when the cases were deemed doubtful (Studies 1 and 2)

    Building an Open Social Learning Community Around a DSpace Repository on Statistics

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    4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PostersIn this paper we describe a project which aims to build an open social learning community around a learning object repository (LOR) based on DSpace containing learning resources about Statistics. We combine the preservation capabilities of DSpace with the facilities of a tagging mechanism such as Delicious. On top of this ensemble we intend to build a new browsing interface for improving users' learning experience when using the LOR. We also intend to gather and analyze usage data in order to better understand the real learning process in virtual learning environments.Spanish Government Grant under Refs. TIN2006-15107-C06 and EA2008-015

    Backwater controls of avulsion location on deltas

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    River delta complexes are built in part through repeated river-channel avulsions, which often occur about a persistent spatial node creating delta lobes that form a fan-like morphology. Predicting the location of avulsions is poorly understood, but it is essential for wetland restoration, hazard mitigation, reservoir characterization, and delta morphodynamics. Following previous work, we show that the upstream distance from the river mouth where avulsions occur is coincident with the backwater length, i.e., the upstream extent of river flow that is affected by hydrodynamic processes in the receiving basin. To explain this observation we formulate a fluvial morphodynamic model that is coupled to an offshore spreading river plume and subject it to a range of river discharges. Results show that avulsion is less likely in the downstream portion of the backwater zone because, during high-flow events, the water surface is drawn down near the river mouth to match that of the offshore plume, resulting in river-bed scour and a reduced likelihood of overbank flow. Furthermore, during low-discharge events, flow deceleration near the upstream extent of backwater causes enhanced deposition locally and a reduced channel-fill timescale there. Both mechanisms favor preferential avulsion in the upstream part of the backwater zone. These dynamics are fundamentally due to variable river discharges and a coupled offshore river plume, with implications for predicting delta response to climate and sea level change, and fluvio-deltaic stratigraphy

    Fundamental studies in X-ray astrophysics

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    An analytical model calculation of the ionization structure of matter accreting onto a degenerate dwarf was carried out. Self-consistent values of the various parameters are used. The possibility of nuclear burning of the accreting matter is included. We find the blackbody radiation emitted from the stellar surface keeps hydrogen and helium ionized out to distances much larger than a typical binary separation. Except for low mass stars or high accretion rates, the assumption of complete ionization of the elements heavier than helium is a good first approximation. For low mass stars or high accretion rates the validity of assuming complete ionization depends sensitivity on the distribution of matter in the binary system

    Is the critical Shields stress for incipient sediment motion dependent on channel-bed slope?

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    Data from laboratory flumes and natural streams show that the critical Shields stress for initial sediment motion increases with channel slope, which indicates that particles of the same size are more stable on steeper slopes. This observation is contrary to standard models that predict reduced stability with increasing slope due to the added downstream gravitational force. Processes that might explain this discrepancy are explored using a simple force-balance model, including increased drag from channel walls and bed morphology, variable friction angles, grain emergence, flow aeration, and changes to the local flow velocity and turbulent fluctuations. Surprisingly, increased drag due to changes in bed morphology does not appear to be the cause of the slope dependency because both the magnitude and trend of the critical Shields stress are similar for flume experiments and natural streams, and significant variations in bed morphology in flumes is unlikely. Instead, grain emergence and changes in local flow velocity and turbulent fluctuations seem to be responsible for the slope dependency due to the coincident increase in the ratio of bed-roughness scale to flow depth (i.e., relative roughness). A model for the local velocity within the grain-roughness layer is proposed based on a 1-D eddy viscosity with wake mixing. In addition, the magnitude of near-bed turbulent fluctuations is shown to depend on the depth-averaged flow velocity and the relative roughness. Extension of the model to mixed grain sizes indicates that the coarser fraction becomes increasingly difficult to transport on steeper slopes

    A model for fluvial bedrock incision by impacting suspended and bed load sediment

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    A mechanistic model is derived for the rate of fluvial erosion into bedrock by abrasion from uniform size particles that impact the bed during transport in both bed and suspended load. The erosion rate is equated to the product of the impact rate, the mass loss per particle impact, and a bed coverage term. Unlike previous models that consider only bed load, the impact rate is not assumed to tend to zero as the shear velocity approaches the threshold for suspension. Instead, a given sediment supply is distributed between the bed and suspended load by using formulas for the bed load layer height, bed load velocity, logarithmic fluid velocity profile, and Rouse sediment concentration profile. It is proposed that the impact rate scales linearly with the product of the near-bed sediment concentration and the impact velocity and that particles impact the bed because of gravitational settling and advection by turbulent eddies. Results suggest, unlike models that consider only bed load, that the erosion rate increases with increasing transport stage (for a given relative sediment supply), even for transport stages that exceed the onset of suspension. In addition, erosion can occur if the supply of sediment exceeds the bed load transport capacity because a portion of the sediment load is transported in suspension. These results have implications for predicting erosion rates and channel morphology, especially in rivers with fine sediment, steep channel-bed slopes, and large flood events

    Theory of collision effects on line shapes using a quantum mechanical description of the atomic center of mass motion - Application to lasers

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    Quantum mechanical treatment of atomic center of mass motion in theory of collision effects on line shape

    The Effects Of Rapport-Building Style on Children’s Reports of a Staged Event

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    Three- to 9-year-old children (N = 144) interacted with a photographer and were interviewed about the event either a week or a month later. The informativeness and accuracy of information provided following either open-ended or direct rapport building were compared. Children in the open-ended rapport-building condition provided more accurate reports than children in the direct rapport-building condition after both short and long delays. Open-ended rapport-building led the 3- to 4-year-olds to report more errors in response to the first recall question about the event, but they went on to provide more accurate reports in the rest of the interview than counterparts in the direct rapport-building condition. These results suggest that forensic interviewers should attempt to establish rapport with children using an open-ended style
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