7,659 research outputs found

    Correction function in the Lidar equation and the solution techniques for CO2 Lidar date reduction

    Get PDF
    For lidar systems with long laser pulses the unusual behavior of the near-range signals causes serious difficulties and large errors in reduction. The commonly used lidar equation is no longer applicable since the convolution of the laser pulse with the atmospheric parameter distributions should be taken into account. It is important to give more insight into this problem and find the solution techniques. Starting from the original equation, a general form is suggested for the single scattering lidar equation where a correction function Cr is introduced. The correction Function Cr(R) derived from the original equation indicates the departure from the normal lidar equation. Examples of Cr(R) for a coaxial CO2 lidar system are presented. The Differential Absorption Lidar (DIAL) errors caused by the differences of Cr(R) for H2O measurements are plotted against height

    Exploring the Influence of Peer-Assisted Learning Strategies (PALS) in Increasing Reading Comprehension of Grade-Level Biology Text and Biology Self-Efficacy in Students with Learning Disabilities: A Formative Experiment

    Get PDF
    The present study used a formative design experiment framework which does not answer a research question but addresses a pedagogical goal. The goal of this study was to determine the influence of Peer-Assisted Learning Strategies (PALS) on the reading comprehension of grade-level biology text and biology self-efficacy with students diagnosed with learning disabilities. As a result of this intervention, it was expected that students would better understand biology text and feel better about themselves as a biology student. Students were separated into pairs, or dyads, with each pair having a stronger reader and a weaker reader. These dyads participated in a series of three structured learning activities: Partner Reading, Paragraph Shrinking and Prediction Relay. Biology self-efficacy assessments and researcher-developed reading comprehensive assessments were administered both pre-and postintervention and after each biology unit. Student notebooks, the researcher notebook, teacher interviews, and focus student interviews were used to gather qualitative data throughout the study. The results suggested that the PALS intervention can have a positive effect on the reading comprehension of grade-level biology text and biology self-efficacy for students with learning disabilities

    Hemispheric specialization in selective attention and short-term memory: a fine-coarse model of left- and right-ear disadvantages.

    Get PDF
    Serial short-term memory is impaired by irrelevant sound, particularly when the sound changes acoustically. This acoustic effect is larger when the sound is presented to the left compared to the right ear (a left-ear disadvantage). Serial memory appears relatively insensitive to distraction from the semantic properties of a background sound. In contrast, short-term free recall of semantic-category exemplars is impaired by the semantic properties of background speech and is relatively insensitive to the sound’s acoustic properties. This semantic effect is larger when the sound is presented to the right compared to the left ear (a right-ear disadvantage). In this paper, we outline a speculative neurocognitive fine-coarse model of these hemispheric differences in relation to short-term memory and selective attention, and explicate empirical directions in which this model can be critically evaluated

    Gamones and mating types in the genus Blepharisma and their possible taxonomic application

    Get PDF
    SUMMARYMating types I and II ofBlepharisma japonicum v. intermediumexcrete gamones 1 (blepharmone J) and 2 (blepharismone) respectively. The gamone of one type transforms cells of the other type so that they can conjugate with each other. We found that three other species,B. americanum, B. musculusandB. stoltei, have two types of cells homologous to those inB. japonicum; one (type II) excretes a factor which has the same activity as gamone 2 ofB. japonicum, the other (type I) responds to this gamone by cell union. Type I cells of these species also excrete a gamone which induces pairs in type II cells of particular strains. Complementarity for mating is observed in some combinations of the two types.These results indicate that each of the four species has at least one pair of complementary mating types, I and II, with the gamones of the type II's being the same molecule, blepharismone, while gamones of type I's are species- or syngen-specific blepharmone. These generic and specific gamones can be utilized to clarify existing taxonomic and evolutionary questions in the genusBlepharisma

    Behavioral flexibility vs. rules of thumb: how do grey squirrels deal with conflicting risks?

    Get PDF
    In order to test how flexibly animals are able to behave when making trade-offs that involve assessing constantly changing risks, we examined whether wild Eastern grey squirrels showed flexibility of behavioral responses in the face of variation in two conflicting risks, cache pilferage and predation. We established that cache pilferage risk decreased with distance from cover, and was thus negatively correlated with long-term predation risk. We then measured changes in foraging and food caching behavior in the face of changes in the risk of predation and food theft over a short time-scale. We found that, overall, squirrels move further away from the safety of cover when they cache, compared to when they forage, as predicted by pilferage risk. However, there was no effect of immediate pilferage or predation risk (i.e. the presence of potential predators or pilferers) on the distance from cover at which they cached, and only a slight increase in forage distance when predation risk increased. These results suggest that ‘rules of thumb’ based on static cues may be more cost-effective for assessing risk than closely tracking changes over time in the way suggested by a number of models of risk assessment

    Implementasi Kebijakan Pemberdayaan Masyarakat Pesisir Di Kelurahan Tanjung Mas Kota Semarang

    Full text link
    Empowerment of coastal communities as one solution to increase the welfare of society at this time has not been well established. About 32.4% of coastal communities in Indonesia are still in the poverty line as a result of the management of coastal areas are less precise. This study aims to analyze the implementation of coastal communities empowerment policy in the Villages of Tanjung Mas as well as identify the factor are supporting and inhibiting implementation than to formulate efforts that we need to create for the effectively implementation of coastal communities empowerment policy. The results showed that the implementation of Perda Semarang No. 23 in 2011 about the management of coastal area has not yet reached the goal of empowerment according. This occurs because the existence of NGOS as implementing community empowerment actors not yet seen, community empowerment for individuals not yet implemented, the Government of Semarang City have not compiled technical guidelines at the discretion of coastal communities empowerment, and the distribution of beneficiaries of policies have not been evenly distributed. Based on the shortage of necessary efforts increased participation of NGOS, draw up technical guidelines for coastal community empowerment as a priority, doing mapping of potential inhabitants, and encouraging the public to participate in environmental conservation

    Vertical head rotation as major source of differences between time-separated digital cephalometric radiographs of patients acquired in one cephalostat X-ray device.

    Get PDF
    BACKGROUND The purpose of the retrospective study was to analyze the reliability and repeatability of specific landmark-positions used in cephalometry to determine the major sources of absolute landmark position differences for repeated, time-separated (time-point I and II) digital cephalometric radiographs (CEPH) of the same patients. METHODS 100 pairs of CPEHs from the database of a sample of adult patients (18 to 28 years) were analyzed by one calibrated observer and three landmark points (Sella: S, Nasion: N, Subspinale: A) were digitally marked using ImageJ-software. The coordinates of these points entered the evaluation using displacement vectors as primary endpoints between the coordinates of the landmarks in the two images as well as SNA-angles and the angle ω of SN relative to the floor. RESULTS Displacement vectors between CEPHI and CEPHII were rather large (N: 7.95 ± 4.85 mm, S: 5.34 ± 3.50 mm, A: 4.81 ± 3.95 mm. SNA was rather stable between the two sequential radiographs (mean difference: 0.002° ± 1.85°). and did not correlate with age of the patient (SNAI: spearman-Rho: 0.0239, p = 0.8134; SNAII : spearman-Rho: 0.0244, p = 0.8096). Although the vertical angle ω did not differ between CEPHI and CEPHII (mean difference: 0.4° ± 4.7°, pwilcoxon = 0.8155), it showed a quadratic relationship (pF-statistic: < 2.2e-16) with the length of the displacement vector N. CONCLUSION The significantly varying location of the reference points S, N and A between time-separated CEPHs of one patient can largely be explained by different angulation (head rotation within the sagittal plane) of the Frankfurt plane to the floor (horizontal plane)

    Magneto-shear modes and a.c. dissipation in a two-dimensional Wigner crystal

    Full text link
    The a.c. response of an unpinned and finite 2D Wigner crystal to electric fields at an angular frequency ω\omega has been calculated in the dissipative limit, ωτ1\omega \tau \ll 1, where τ1\tau ^{-1} is the scattering rate. For electrons screened by parallel electrodes, in zero magnetic field the long-wavelength excitations are a diffusive longitudinal transmission line mode and a diffusive shear mode. A magnetic field couples these modes together to form two new magneto-shear modes. The dimensionless coupling parameter β=2(ct/cl)σxy/σxx\beta =2(c_{t}/c_{l})|\sigma_{xy}/\sigma_{xx}| where ctc_{t} and clc_{l} are the speeds of transverse and longitudinal sound in the collisionless limit and σxy\sigma_{xy} and σxx\sigma_{xx} are the tensor components of the magnetoconductivity. For β1\beta \geqslant 1, both the coupled modes contribute to the response of 2D electrons in a Corbino disk measurement of magnetoconductivity. For β1\beta \gg 1, the electron crystal rotates rigidly in a magnetic field. In general, both the amplitude and phase of the measured a.c. currents are changed by the shear modulus. In principle, both the magnetoconductivity and the shear modulus can be measured simultaneously.Comment: REVTeX, 7 pp., 4 eps figure

    Behavioural responses of Eastern grey squirrels, Sciurus carolinensis, to cues of risk while foraging

    Get PDF
    Lisa Leaver University of Exeter Psychology Washington Singer Exeter Devon EX4 4QG UKArticleCopyright © 2015 Elsevier B.V. All rights reserved.Previous studies have shown that Eastern grey squirrels modify their behaviour while foraging to offset risks of social and predatory costs, but none have simultaneously compared whether such modifications are performed at a cost to foraging. The present study directly compares how grey squirrels respond to cues of these risks while foraging. We simulated social risk and predatory risk using acoustic playbacks of stimuli that grey squirrels might be exposed to at a foraging patch: calls of conspecifics, heterospecifics (competitor and non-competitor) and predators. We found that grey squirrels responded to predator, heterospecific competitor and conspecific playbacks by altering their foraging and vigilance behaviours. Foraging was most disrupted by increased vigilance when we played calls of predators. Squirrels' response to calls of heterospecific competitors did not differ from their response to conspecific calls, and they resumed foraging more quickly after both compared to predator calls: whereas they showed little response to calls of non-competitor heterospecifics and a white noise control. We conclude that squirrels respond differentially to calls made by conspecifics, heterospecific competitors and predators, with the most pronounced response being to calls of predators. We suggest that squirrels may view conspecific and corvid vocalisations as cues of potential conflict while foraging, necessitating increased vigilance.Exeter Graduate Fellow scholarshi
    corecore