Event rates vs. cross sections at neutrino telescopes

One of the major goals of neutrino astronomy is to explore the otherwise unknown fluxes and interactions of ultrahigh energy neutrinos. The existing neutrino telescopes look at three types of events: particle showers, muons, and taus. In this paper we discuss the dependence of the event rates on the neutrino nucleon cross-sections as we scale the cross sections, with energy, in different scenarios beyond the standard model. Our focus will be on the IceCube detector.Comment: 3 pages, 2 figures; proceedings of the "TeV Particle Astrophysics II", Madison, Wisconsin; to be published in the Journal of Physics: Conference Serie

Simulation of the radio signal from ultrahigh energy neutrino-initiated showers

PeV neutrinos produce particle showers when they interact with the atomic nuclei in ice. We briefly describe characteristics of these showers and the radio Cherenkov signal produced by the showers. We study pulses from electromagnetic (em), hadronic, and combined em-hadronic showers and propose extrapolations to EeV energies.Comment: Made changes in figure captions and reference 6. 3 pages, to appear in "Lake Louise Winter Institute 2004" conference proceeding

EFFECTS OF INTERNET ON EDUCATIONAL ACHIEVEMENTS, SOCIAL CAPITAL AND LIFE PATTERN OF YOUTH

This research study aimed at exploring the extent of internet usage among youth studying in various colleges and universities of twin cities of Rawalpindi/Islamabad and its ultimate effects on their educational achievements, life pattern and social capital. The study also tested the Time Displacement Hypothesis of Robert Putnam (1995), which postulates that heavy usage of media causes decline in the Social Capital and interpersonal communication of users with family, colleagues and friends and also decreases the social and physical activities of the users. The data has been collected from 500 students of Intermediate to PhD level studying in various colleges and universities of Rawalpindi and Islamabad through a survey with the help of a self-administered questionnaire. The results show that the study has not supported the Time Displacement Hypothesis of Robert Putnam (1995). The regression model has not showed any positive relationship between internet use and its negative effects on the educational achievements, life pattern and social capital of youth. However, the habit of exercise/games among youth has been found badly affected due to the exposure to internet

STABILIZED NUMERICAL METHODS FOR THE TWO KINDS OF PROBLEMS OF INCOMPRESSIBLE FLUID FLOWS

A mixed finite element method (MFEM) stabilized for the two kinds of problems related to the incompressible fluid flow is demonstrated. In the first kind, the Newtonian fluid flow is illustrated with the MFEM and considered discontinuous scheme. Initially, the model equations are considered nonlinear and un-stabilize. The model equations are solved for linear terms with the special technique first and then the model equation with the extra added term is utilized later to stabilize the model equations. A steady-state viscoelastic Oseen fluid flow model with Oldroyd-B type formulations was demonstrated in the second kind of problem with SUPG method. The nonlinear problems are linearized through the Oseen scheme. Numerical results for both the model equations are given and compared. The SUPG method is found more suitable and active

EFFECTS OF VIDEO-PODCASTS ON LISTENING COMPREHENSION OF SAUDI EFL LEARNERS

The current use of podcasts, as a new channel to input knowledge, has effectively been promoting listening comprehension which consequently has increased the acquisition of target language. The objective of the present study is to investigate the effects of video-podcasts integration on listening comprehension. The twelve-week quantitative study employed a quasi-experimental pre-test post-test design. Samples included in both the control and experimental groups were 120 English major male undergraduates from a University in Saudi Arabia. The Findings of ANCOVA analysis showed that the video-podcast group significantly outperformed the control group on the post-test. The findings imply that video-podcasts are useful resource for enhancing EFL learners’ listening comprehension

SAUDI EFL LEARNERS’ ATTITUDE TOWARDS INTEGRATION OF VIDEO-PODCASTS IN LISTENING COMPREHENSION

The use of podcasts is growing in the instructions of listening comprehension. However, the success of computer technology generally depends on learners positive attitudes towards it. The present study explored attitudes of Saudi EFL undergraduates toward the use of video-podcasts integration in listening comprehension. Moreover, the study also examined students’ attitude from the perspective of the number of video-podcasts they received in their instructions. Samples included 90 English major male undergraduates divided into three groups. The three groups received five (5), ten (10) and 15 video-podcasts in their listening classes before they answered an attitude questionnaire. ANOVA results revealed that the students had positive attitudes towards the use of video-podcasts in listening. However, no significant difference was found between the attitudes of the three experimental groups who received varied number of video-podcasts in their instructions.   Article visualizations

Peak to average power ratio based spatial spectrum sensing for cognitive radio systems

The recent convergence of wireless standards for incorporation of spatial dimension in wireless systems has made spatial spectrum sensing based on Peak to Average Power Ratio (PAPR) of the received signal, a promising approach. This added dimension is principally exploited for stream multiplexing, user multiplexing and spatial diversity. Considering such a wireless environment for primary users, we propose an algorithm for spectrum sensing by secondary users which are also equipped with multiple antennas. The proposed spatial spectrum sensing algorithm is based on the PAPR of the spatially received signals. Simulation results show the improved performance once the information regarding spatial diversity of the primary users is incorporated in the proposed algorithm. Moreover, through simulations a better performance is achieved by using different diversity schemes and different parameters like sensing time and scanning interval