Comparison of Leaf Reflectance of Sorghum Plants Infested by Sugarcane Aphids

Sugarcane aphid, Melanaphis sacchari (Homiptera: Aphididae; Fig. 1A), is a significant pest to sorghum, Sorghum bicolor (Fig. 1B). Sorghum fields are regularly surveyed to detect pest infestation. Remote sensing methods using satellite and aircraft data are expected to provide an efficient alternative to field surveys. However, spectral signature of sugarcane aphid infested sorghum plants is not well understood. We evaluated reflectance spectra of sorghum leaves infested by sugarcane aphids. We used those spectral data to estimate indices that are related to photosynthetic pigments such as chlorophyll', anthocyanin, and carotenoids. We also estimated an aphid index, damage sensitive spectral index (DSSI)". We used these data to examine whether indices differ between pest infested and uninfested plants. We predicted that plants infested by aphid will have higher levels of anthocyanin, carotenoids, and DSSI indices compared to the control plants. In contrary, chlorophyll index will be greater for uninfested plants

Coherent optical non-reciprocity in axisymmetric resonators

We describe an approach to optical non-reciprocity that exploits the local helicity of evanescent electric fields in axisymmetric resonators. By interfacing an optical cavity to helicity-sensitive transitions, such as Zeeman levels in a quantum dot, light transmission through a waveguide becomes direction-dependent when the state degeneracy is lifted. Using a linearized quantum master equation, we analyze the configurations that exhibit non-reciprocity, and we show that reasonable parameters from existing cavity QED experiments are sufficient to demonstrate a coherent non-reciprocal optical isolator operating at the level of a single photon.Comment: 15 pages, 7 figure

Control of long-range correlations in turbulence

The character of turbulence depends on where it develops. Turbulence near boundaries, for instance, is different than in a free stream. To elucidate the differences between flows, it is instructive to vary the structure of turbulence systematically, but there are few ways of stirring turbulence that make this possible. In other words, an experiment typically examines either a boundary layer or a free stream, say, and the structure of the turbulence is fixed by the geometry of the experiment. We introduce a new active grid with many more degrees of freedom than previous active grids. The additional degrees of freedom make it possible to control various properties of the turbulence. We show how long-range correlations in the turbulent velocity fluctuations can be shaped by changing the way the active grid moves. Specifically, we show how not only the correlation length but also the detailed shape of the correlation function depends on the correlations imposed in the motions of the grid. Until now, large-scale structure had not been adjustable in experiments. This new capability makes possible new systematic investigations into turbulence dissipation and dispersion, for example, and perhaps in flows that mimic features of boundary layers, free streams, and flows of intermediate character.Comment: This paper has been accepted to Experiments in Fluids. 25 pages, 10 figure

Measuring the translational and rotational velocity of particles in helical motion using structured light

We measure the rotational and translational velocity components of particles moving in helical motion using the frequency shift they induced to the structured light beam illuminating them. Under Laguerre-Gaussian mode illumination, a particle with a helical motion reflects light that acquires an additional frequency shift proportional to the angular velocity of rotation in the transverse plane, on top of the usual frequency shift due to the longitudinal motion. We determined both the translational and rotational velocities of the particles by switching between two modes: by illuminating with a Gaussian beam, we can isolate the longitudinal frequency shift; and by using a Laguerre-Gaussian mode, the frequency shift due to the rotation can be determined. Our technique can be used to characterize the motility of microorganisms with a full three-dimensional movement.Comment: 5 pages,5 figure

STUDENT’S ATTITUDE TOWARDS DICTIONARY AND ITS USAGE : A Case of Study for English Department Students Diponegoro University

In learning a foreign language, dictionary is one of learning aids to assist students in making decision about making sense of words in usage –in the target language. This research is conducted to discover how English Department students in Universitas Diponegoro perceive dictionary and use it to assist meaning discovery. The data in this paper is obtained from returned questionnaires previously distributed across four academic years in. The results show that dictionary is not the primary source of English vocabulary intake. Most dictionaries are bilingual (English-Indonesian or Indonesian-English), and may take the form of printed or electronic dictionary. We also discovered that the respondents tend to choose a dictionary based on the number of words listed. Further clarifications of the respondents’ answers indicate the preference of vocabulary intake, where dictionary is not a priority. Bilingual dictionaries are preferred as compared to monolingual ones with the assumption that they are easier to understand. Although the definition of word is still very loose, students seem to be more attracted to dictionaries, which claim to have vast number of entries. For practical purposes, portable dictionary or application dictionary is more preferred as they support mobility. From the results, we may conclude that dictionaries are used by the respondents with restriction in meaning discovery. We suggest that they take it to the next level, where existing linguistic features from dictionaries might also be used to assist writing

Can Neuroscience Help Predict Future Antisocial Behavior?

Part I of this Article reviews the tools currently available to predict antisocial behavior. Part II discusses legal precedent regarding the use of, and challenges to, various prediction methods. Part III introduces recent neuroscience work in this area and reviews two studies that have successfully used neuroimaging techniques to predict recidivism. Part IV discusses some criticisms that are commonly levied against the various prediction methods and highlights the disparity between the attitudes of the scientific and legal communities toward risk assessment generally and neuroscience specifically. Lastly, Part V explains why neuroscience methods will likely continue to help inform and, ideally, improve the tools we use to help assess, understand, and predict human behavior

Frequency conversion of structured light

We demonstrate the coherent frequency conversion of structured light, optical beams in which the phase varies in each point of the transverse plane, from the near infrared (803nm) to the visible (527nm). The frequency conversion process makes use of sum-frequency generation in a periodically poled lithium niobate (ppLN) crystal with the help of a 1540-nm Gaussian pump beam. We perform far-field intensity measurements of the frequency-converted field, and verify the sought-after transformation of the characteristic intensity and phase profiles for various input modes. The coherence of the frequency-conversion process is confirmed using a mode-projection technique with a phase mask and a single-mode fiber. The presented results could be of great relevance to novel applications in high-resolution microscopy and quantum information processing