2,712 research outputs found

    Comparing Learning Platform Impact on Low Vision Education for Occupational Therapists

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    This pilot study examines the impact of face-to-face, remote, and hybrid learning platforms on satisfaction, confidence, and knowledge-application of occupational therapy practitioners during a synchronous low vision continuing education program. Fifteen participants were divided into three groups, each corresponding to one learning platform. They engaged in two 45-min learning sessions and completed pre, post, and follow-up surveys to measure the impact of the learning platform on the dependent variables of satisfaction, confidence, and knowledge application. No significant differences were found between learning platforms for the three variables, but improvements from pre to follow-up survey were found to be significant for confidence and knowledge application for all groups. These findings indicate that similar education provided to occupational therapy practitioners may result in improved confidence and knowledge application to clinical practice from the beginning to the end of the educational program, despite the learning platform. Flexibility with online learning options increased participation and adherence rates. Synchronous remote and hybrid learning platforms may be as effective as traditional face-to-face methods, specifically with increasing practitioner confidence and knowledge application. Remote options may reduce peer interactions but increase flexibility and convenience with scheduling for program scalability and accessibility

    Forming first-ranked early-type galaxies through hierarchical dissipationless merging

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    We have developed a computationally competitive N-body model of a previrialized aggregation of galaxies in a flat LambdaCDM universe to assess the role of the multiple mergers that take place during the formation stage of such systems in the configuration of the remnants assembled at their centres. An analysis of a suite of 48 simulations of low-mass forming groups (of about 1E13 solar masses) demonstrates that the gravitational dynamics involved in their hierarchical collapse is capable of creating realistic first-ranked galaxies without the aid of dissipative processes. Our simulations indicate that the brightest group galaxies (BGGs) constitute a distinct population from other group members, sketching a scenario in which the assembly path of these objects is dictated largely by the formation of their host system. We detect significant differences in the distribution of Sersic indices and total magnitudes, as well as a luminosity gap between BGGs and the next brightest galaxy that is positively correlated with the total luminosity of the parent group. Such gaps arise from both the grow of BGGs at the expense of lesser companions and the decrease in the relevance of second-ranked objects in equal measure. This results in a dearth of intermediate-mass galaxies which explains the characteristic central dip detected in their luminosity functions in dynamically young galaxy aggregations. The fact that the basic global properties of our BGGs define a thin mass fundamental plane strikingly similar to that followed giant early-type galaxies in the local universe reinforces confidence in the results obtained.Comment: 25 pages, 14 figures, 3 tables. Accepted to MNRA

    Polarization entanglement visibility of photon pairs emitted by a quantum dot embedded in a microcavity

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    We study the photon emission from a quantum dot embedded in a microcavity. Incoherent pumping of its excitons and biexciton provokes the emission of leaky and cavity modes. By solving a master equation we obtain the correlation functions required to compute the spectrum and the relative efficiency among the emission of pairs and single photons. A quantum regime appears for low pumping and large rate of emission. By means of a post-selection process, a two beams experiment with different linear polarizations could be performed producing a large polarization entanglement visibility precisely in the quantum regime.Comment: 13 pages and 6 figure

    Dynamics of the excitations of a quantum dot in a microcavity

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    We study the dynamics of a quantum dot embedded in a three-dimensional microcavity in the strong coupling regime in which the quantum dot exciton has an energy close to the frequency of a confined cavity mode. Under the continuous pumping of the system, confined electron and hole can recombine either by spontaneous emission through a leaky mode or by stimulated emission of a cavity mode that can escape from the cavity. The numerical integration of a master equation including all these effects gives the dynamics of the density matrix. By using the quantum regression theorem, we compute the first and second order coherence functions required to calculate the photon statistics and the spectrum of the emitted light. Our main result is the determination of a range of parameters in which a state of cavity modes with poissonian or sub-poissonian (non-classical) statistics can be built up within the microcavity. Depending on the relative values of pumping and rate of stimulated emission, either one or two peaks close to the excitation energy of the dot and/or to the natural frequency of the cavity are observed in the emission spectrum. The physics behind these results is discussed

    Using adult mosquitoes to transfer insecticides to Aedes aegypti larval habitats.

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    Vector control is a key means of combating mosquito-borne diseases and the only tool available for tackling the transmission of dengue, a disease for which no vaccine, prophylaxis, or therapeutant currently exists. The most effective mosquito control methods include a variety of insecticidal tools that target adults or juveniles. Their successful implementation depends on impacting the largest proportion of the vector population possible. We demonstrate a control strategy that dramatically improves the efficiency with which high coverage of aquatic mosquito habitats can be achieved. The method exploits adult mosquitoes as vehicles of insecticide transfer by harnessing their fundamental behaviors to disseminate a juvenile hormone analogue (JHA) between resting and oviposition sites. A series of field trials undertaken in an Amazon city (Iquitos, Peru) showed that the placement of JHA dissemination stations in just 3-5% of the available resting area resulted in almost complete coverage of sentinel aquatic habitats. More than control mortality occurred in 95-100% of the larval cohorts of Aedes aegypti developing at those sites. Overall reductions in adult emergence of 42-98% were achieved during the trials. A deterministic simulation model predicts amplifications in coverage consistent with our observations and highlights the importance of the residual activity of the insecticide for this technique

    Unveiling the formation route of the largest galaxies in the Universe

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    Observational evidence indicates that the role of gas is secondary to that of gravity in the formation of the most luminous spheroids inhabiting the centres of galaxy associations, as originally conjectured in the late 80s/early 90s. However, attempts to explain the origin of the Fundamental Plane (FP) of massive early-type galaxies (ETGs) - a tilted version of the scaling relation connecting the size, velocity dispersion and mass of virialized homologous systems - based on sequences of pairwise mergers, have systematically concluded that dissipation cannot be ignored. We use controlled simulations of the pre-virialization stage of galaxy groups to show that multiple collisionless merging is capable of creating realistic first-ranked galaxies. Our mock remnants define a thin FP that perfectly fits data from all kinds of giant ETGs in the local volume, showing the existence of a unified relationship for these systems. High-ranked galaxies occupy in the FP different areas than standard objects, a segregation which is viewed essentially as zero-point offsets in the 2D correlations arising from standard projections of this plane. Our findings make a strong case for considering hierarchical dissipationless merging a viable route for the formation of the largest galaxies in the Universe

    Maximum distance separable 2D convolutional codes

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    Maximum distance separable (MDS) block codes and MDS 1D convolutional codes are the most robust codes for error correction within the class of block codes of a fixed rate and 1D convolutional codes of a certain rate and degree, respectively. In this paper, we generalize this concept to the class of 2D convolutional codes. For that, we introduce a natural bound on the distance of a 2D convolutional code of rate k/nk/n and degree deltadelta , which generalizes the Singleton bound for block codes and the generalized Singleton bound for 1D convolutional codes. Then, we prove the existence of 2D convolutional codes of rate k/nk/n and degree deltadelta that reach such bound when ngeqk(((lfloor(delta/k)rfloor+2)(lfloor(delta/k)rfloor+3))/2)n geq k (({(lfloor ({delta }/{k}) rfloor + 2)(lfloor ({delta }/{k}) rfloor + 3)})/{2}) if knmiddeltak {nmid } delta , or ngeqk((((delta/k)+1)((delta/k)+2))/2)n geq k (({(({delta }/{k}) + 1)(({delta }/{k}) + 2)})/{2}) if kmiddeltak mid delta , by presenting a concrete constructive procedure
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