Modulation of Negative Work Output from a Steering Muscle of the Blowfly Calliphora Vicina

Of the 17 muscles responsible for flight control in flies, only the first basalar muscle (b1) is known to fire an action potential each and every wing beat at a precise phase of the wing-beat period. The phase of action potentials in the b1 is shifted during turns, implicating the b1 in the control of aerodynamic yaw torque. We used the work loop technique to quantify the effects of phase modulation on the mechanical output of the b1 of the blowfly Calliphora vicina. During cyclic length oscillations at 10 and 50 Hz, the magnitude of positive work output by the b1 was similar to that measured previously from other insect muscles. However, when tested at wing-beat frequency (150 Hz), the net work performed in each cycle was negative. The twitch kinetics of the b1 suggest that negative work output reflects intrinsic specializations of the b1 muscle. Our results suggest that, in addition to a possible role as a passive elastic element, the phase-sensitivity of its mechanical properties may endow the b1 with the capacity to modulate wing-beat kinematics during turning maneuvers

Game Based Learning for Safety and Security Education

Safety and security education are important part of technology related education, because of recent number of increase in safety and security related incidents. Game based learning is an emerging and rapidly advancing forms of computer-assisted instruction. Game based learning for safety and security education enables students to learn concepts and skills without the risk of physical injury and security breach. In this paper, a pedestal grinder safety game and physical security game have been developed using industrial standard modeling and game development software. The average score of the knowledge test of grinder safety game was 82%, which is higher than traditional lecture only instruction method. In addition, the survey of physical security game shows 84% average satisfaction ratio from high school students who played the game during the summer camp. The results of these studies indicated that game based learning method can enhance students' learning without potential harm to the students

Strongly interacting neutrinos as the highest energy cosmic rays

We show that all features of the ultrahigh energy cosmic ray spectrum from 10^{17} eV to 10^{21} eV can be described with a simple power-like injection spectrum of protons under the assumption that the neutrino-nucleon cross-section is significantly enhanced at center of mass energies above \approx 100 TeV. In our scenario, the cosmogenic neutrinos produced during the propagation of protons through the cosmic microwave background initiate air showers in the atmosphere, just as the protons. The total air shower spectrum induced by protons and neutrinos shows excellent agreement with the observations. A particular possibility for a large neutrino-nucleon cross-section exists within the Standard Model through electroweak instanton-induced processes.Comment: 8 pages, 4 figures, talk given at Beyond the Desert '03, Castle Ringberg, 9-14 June, 200

Quantitative assessment of Earth’s radiation belt modeling

The “Quantitative Assessment of Radiation Belt Modeling” focus group was in place at Geospace Environment Modeling from 2014 to 2018. The overarching goals of this focus group were to bring together the current state‐of‐the‐art models for the acceleration, transport, and loss processes in Earth's radiation belts; develop event‐specific and global inputs of wave, plasma, and magnetic field to drive these models; and combine all these components to achieve a quantitative assessment of radiation belt modeling by validating against contemporary radiation belt measurements. This article briefly reviews the current understanding of radiation belt dynamics and related modeling efforts, summarizes the activities and accomplishments of the focus group, and discusses future directions.Accepted manuscrip

Quantitative assessment of radiation belt modeling

The “Quantitative Assessment of Radiation Belt Modeling” focus group was in place at Geospace Environment Modeling from 2014 to 2018. The overarching goals of this focus group were to bring together the current state‐of‐the‐art models for the acceleration, transport, and loss processes in Earth's radiation belts; develop event‐specific and global inputs of wave, plasma, and magnetic field to drive these models; and combine all these components to achieve a quantitative assessment of radiation belt modeling by validating against contemporary radiation belt measurements. This article briefly reviews the current understanding of radiation belt dynamics and related modeling efforts, summarizes the activities and accomplishments of the focus group, and discusses future directions.Accepted manuscrip

In search of the ‘best’ option: American private secondary education for upper-middle-class Chinese teenagers

This article focuses on unpacking the processes of how a rapidly rising group of urban upper-middle-class Chinese families decide to send their only children to the United States on their own for private secondary education. The article analyzes the socio-historical background of such choice and lays out these families’ various paths to opting out of the neoliberal school-choice market in China and eyeing American private secondary education as the ‘best’ option. Based on in-depth interviews with 33 parents in several Chinese mega-cities, the author demonstrates that Chinese urban upper-middle-class families choose such a transnational educational choice as a silent exit from the anxiety-ridden Chinese education system. Situated in the socio-historical transformation of contemporary Chinese society, the reasons for exiting range from dissatisfaction with the political narrative to educational aspiration of a ‘well-rounded’ education and resistance against the test-oriented pedagogical practices at school. This ethnographic research provides a unique perspective to engage with works on elite education in a global context and enriches the theorization of the global middle classes.Cet article s’attache à éclaicir les processus par lesquels un nombre de plus en plus important de familles chinoises de classe moyenne supérieure décident d’envoyer leur enfant unique faire ses études secondaires dans un établissement privé aux États-Unis. J’analyse le contexte socio-historique d’un tel choix et expose les différentes voies qui mènent ces familles à renoncer à choisir une école sur le marché néolibéral chinois et à considérer l’enseignement secondaire privé américain comme la « meilleure » option. Sur la base d’entretiens approfondis avec 33 parents dans plusieurs mégapoles chinoises, je montre que les familles urbaines de la classe moyenne supérieure chinoise opèrent un tel choix éducatif transnational comme une manière silencieuse de sortir d’un système éducatif chinois particulièrement anxiogène. Dans le contexte contemporain de transformation socio-historique de la société chinoise, les raisons de cette sortie vont de l’insatisfaction à l’égard du discours politique à l’aspiration à une éducation « complète », en passant par une résistance aux pratiques pédagogiques axées sur les tests à l’école. Cette recherche ethnographique offre une perspective unique pour participer à des travaux sur l’éducation des élites dans un contexte mondial et apporte de nouveaux éléments à la théorisation des classes moyennes mondiales.Este artículo se centra en analizar los procesos a través de lo que un número creciente de familias chinas urbanas de clase media alta deciden enviar a sus hijos únicos a realizar sus estudios secundarios en establecimientos privados en Estados Unidos. Se analizan los antecedentes sociohistóricos de esta elección y se exponen los diversos caminos que toman estas familias para optar por salir del mercado neoliberal de elección de escuelas en China y considerar la educación secundaria privada estadounidense como la ‘mejor’ opción. A partir de entrevistas en profundidad con 33 en varias megaciudades chinas, se demuestra que las familias chinas urbanas de clase media alta eligen esta opción educativa transnacional como una manera silenciosa de salir del sistema educativo chino, que produce altos niveles de ansiedad. En el contexto de la transformación sociohistórica de la sociedad china contemporánea, las razones para la salida van desde la insatisfacción con la narrativa política hasta la aspiración educativa de una educación ‘integral’ y la resistencia contra las prácticas pedagógicas en la escuela orientadas a los exámenes. Esta investigación etnográfica proporciona una perspectiva única para participar en trabajos sobre educación de élite en un contexto global y enriquece la teorización de las clases medias globales

Radiance and Doppler shift distributions across the network of the quiet Sun

The radiance and Doppler-shift distributions across the solar network provide observational constraints of two-dimensional modeling of transition-region emission and flows in coronal funnels. Two different methods, dispersion plots and average-profile studies, were applied to investigate these distributions. In the dispersion plots, we divided the entire scanned region into a bright and a dark part according to an image of Fe xii; we plotted intensities and Doppler shifts in each bin as determined according to a filtered intensity of Si ii. We also studied the difference in height variations of the magnetic field as extrapolated from the MDI magnetogram, in and outside network. For the average-profile study, we selected 74 individual cases and derived the average profiles of intensities and Doppler shifts across the network. The dispersion plots reveal that the intensities of Si ii and C iv increase from network boundary to network center in both parts. However, the intensity of Ne viii shows different trends, namely increasing in the bright part and decreasing in the dark part. In both parts, the Doppler shift of C iv increases steadily from internetwork to network center. The average-profile study reveals that the intensities of the three lines all decline from the network center to internetwork region. The binned intensities of Si ii and Ne viii have a good correlation. We also find that the large blue shift of Ne viii does not coincide with large red shift of C iv. Our results suggest that the network structure is still prominent at the layer where Ne viii is formed in the quiet Sun, and that the magnetic structures expand more strongly in the dark part than in the bright part of this quiet Sun region.Comment: 10 pages,9 figure

Analysis of rolling bearing power loss models for twin screw oil injected compressor

The mechanical losses inside a screw compressor limit the performance of the compressor in terms of efficiency. These losses arise due to relative motion between elements inside the screw compressor. The estimation of mechanical losses predicted in the literature is around 10-15% of the total shaft power. One of the elements which contribute significantly to these losses is rolling element bearings. There are numerous mathematical models available which predict power losses in the rolling bearings. The objective of this paper is to study different models to predict power loss for rolling bearings and to predict the power losses for the bearings used for oil injected, twin screw compressor. A comparison between different power loss models for different operating conditions of compressor is also presented in this paper and results of analysis are compared with available experimental observations. The analysis helps to determine suitable power loss model for different operating conditions and more realistic predictions of the power losses. This allows designers for more accurate estimation of the performance of screw compressors