Investigating Network Coherence to Assess Students’ Conceptual Understanding of Energy

Conceptual knowledge is a crucial tool for students to understand scientific phenomena. Knowledge about the structure and function of mental concepts potentially helps science educators to foster the acquisition of this tool. Specifically, the coherence of students’ mental concepts is an intensely discussed issue within the related conceptual change discourse. While former discussions focused on the question of whether these conceptions are coherent or not, recent approaches describe them as dynamic systems behaving more or less coherently in different situations. In this contribution, we captured this dynamic behavior of individual concepts by means of network analysis. Transcribed video data of 16 pairs of students working on four subsequent experiments on energy were transformed into weighted networks, which in turn were characterized by standardized coherence parameters. These coherence parameters and more basic network parameters were correlated with students’ pre-post scores of a multiple-choice test on the energy concept. We found that the coherence parameter is significantly related to the students’ test scores. Even more intense relations are indicated if networks are calculated solely based on conceptual key terms. Implications as well as methodological constraints of this approach are discussed.

The Intersemiosis of Negative Emotions in the Cinematic Discourse: a Psycholinguistic Perspective

This study of the psycholinguistic properties of negative emotions in the English cinematic feature discourse focuses on the establishment of their intersemiosis – the simultaneous multimodal construction of emotional meanings by means of heterogeneous sign systems. The means of meaning construction in the cinematic discourse include linguistic, non-linguistic (prosody, kinesics, etc.) and extra-linguistic (music and kineikonic means), and different modes – acoustic and visual channels for transmitting meanings. The main psycholinguistic properties of cinematic emotions are their inextricable connection with the physiological processes, rootedness in the common human embodied experience, motivational basis; emotions are read as the result of an assessment of the satisfaction degree of individuals’ needs. The construction of emotional meanings in the cinematic discourse is the result of the interaction between the real world of the film makers and the imaginary world of the action. In constructing negative emotional meanings in general and emotions of fear and anger, in particular, the collective author of the cinematic discourse uses different semiotic codes in a parity or non-parity way. In the first case, heterogeneous semiotic codes both serve to denote fear or anger, while in the second, advantage is given to one of heterogeneous codes – linguistic, non- linguistic, and extra-linguistic. Consequently, this leads to the domination of one of the modes of transmitting meanings to the collective viewer – acoustic or visual. According to the coherence parameter of the emotional meaning embodied by various means of the semiosis of fear or anger, individual episodes of the English cinematic feature discourse are either congruent or non-congruent. Being congruent, different codes simultaneously transmit the same emotional meaning; being incongruent, heterogeneous semiotic codes actualize different emotional meanings, which leads to higher expressiveness of such emotions and their more effective influence on the viewer.

Effects of Anisotropic Turbulence on Propagation Characteristics of Partially Coherent Beams with Spatially Varying Coherence

Based on the extended Huygens-Fresnel (eHF) principle, approximate analytical expressions for the spectral density of nonuniformly correlated (NUC) beams are derived with the help of discrete model decompositions. The beams are propagating along horizontal paths through an anisotropic turbulent medium. Based on the derived formula, the influence of the anisotropic turbulence (anisotropy factors, structure parameters) on the evolution of the average intensity, the shift of the intensity maxima and the power-in-the-bucket (PIB) are investigated in detail through numerical examples. It is found that the lateral shifting of the intensity maxima is closely related to the anisotropy factors and the strength of turbulence. Our results also reveal that, in the case of weak turbulence, the beam profile can retain the feature of local intensity sharpness, but this feature degenerates quickly if the strength of the turbulence increases. The value of PIB of the NUC beams can be even higher than that of Gaussian beams by appropriately controlling the coherence parameter in the weak turbulence regime. This feature makes the NUC beams useful for free-space communication.

Coherence resonance in the two-dimensional neural map driven by non-Gaussian colored noise

Based on the two-dimensional (2D) neural map, we investigate the impacts of non-Gaussian colored noise on the firing activity of discrete system. Taking the coherence parameter R to measure the regularity of firing behavior, it is demonstrated that coherence parameter R has a pronounced minimum value with the noise intensity and the correlation time of non-Gaussian colored noise, which is the so-called phenomenon of coherence resonance (CR). Besides, the firing activity is not sensitive to the non-Gaussian parameter which determines the departure from the Gaussian distribution when the correlation time is large enough.

Changes in the Beam Parameters of Partially Coherent Sinh-Gaussian Beams after Passage through an Astigmatic Lens

Based on the propagation law of partially coherent beams, the analytical expression of the beam width, waist positions and the far-field divergence angle of partially coherent sinh-Gaussian (ShG) beams through an astigmatic lens were derived. The effect of astigmatism and spatial coherence parameter on the beam parameters was mainly analyzed. It is found that the beam width depends on the astigmatic coefficient, spatial coherence parameter, decentered parameter, fresnel number and propagation distance in general. The astigmatism results in a difference between the beam widths, waist positions and far-field divergence angles in thexandydirections.

Microwave Emission and Scattering from Ocean Surface Waves in the Southern Beaufort Sea

Estimates of the relationships between geophysical variables and microwave backscatter/emission are important for the evaluation of atmosphere-ocean interaction, as well as energy, and mass transfer across this interface. We evaluate ship-based passive microwave brightness temperatures Tb at 37 and 89 GHz and active polarimetric backscatter at 5.5 GHz (C-band), as these relate to buoy-derived ocean wave parameters for distinct wave regimes in the southern Beaufort Sea. Microwave emission and backscatter are shown to be sensitive to the ocean surface physical roughness as defined by the significant wave height Hm0, compared to wind speed. The Tb shows significant correlation with Hm0, with the strongest correlation for the H-polarization channel at 37 and 89 GHz. Active co-γco and cross-γcross polarization ratios at 40° incidence angle are associated with Hm0, with the γco increase proportional to Hm0. The polarimetric coherence parameter ρVVHH at 20° also shows an inverse relationship with Hm0 because of an expected decorrelation of complex returns with greater surface roughness.