6,678 research outputs found
Sliding elastic lattice: an explanation of the motion of superconducting vortices
We introduce a system where an elastic lattice of particles is moved slowly
at a constant velocity under the influence of a local external potential,
construct a rigid-body model through simplification processes, and show that
the two systems produce similar results. Then, we apply our model to a
superconducting vortex system and produce path patterns similar to the ones
reported in [Lee et al., Phys. Rev. B 84, 060515 (2011)] suggesting that the
reasoning of the simplification processes in this paper can be a possible
explanation of the experimentally observed phenomenon.Comment: 5 pages, 3 figures, Submitted to Physical Review Letters; Reference
[17] Lee et al., Phys. Rev. B Accepted changed to Lee et al., Phys. Rev. B
84, 060515 (2011
Evolution of the Pancaking Effect in a LCDM Cosmology
We explore the evolution of the large-scale anisotropy in the velocity field
caused by the gravitational pancaking effect assuming a LCDM universe. The
Millennium Run halo catalogs at four different redshifts, z=0, 0.5, 1 and z=2
are analyzed to find that the pancaking effect starts to intervene the
hierarchical structure formation at redshift z=2 when a characteristic pancake
scale is around 3 Mpc/h. It is also clearly shown how the degree and scale of
the pancaking effect changes with time. An analytic model based on the
Zel'dovich approximation is presented to explain quantitatively the evolution
of the velocity-pancake alignment. A cosmological implication of our finding
and a possibility of detecting a signal in real universe are discussed.Comment: accepted by ApJ, 21 pages, 6 figures, discussion and error analysis
improve
Future Community-Based Ecotourism (CBET) development
Ecotourism is an alternative form of tourism and is usually confused with natural and cultural tourism.CBET is fast becoming a popular biodiversity conservation tool that develops and benefits the local community. Based on the context of conservation theory and practice, Community-Based Ecotourism (CBET) is a form of community-based natural resource management. However, a sustainable CBET development through Community Capacity Building (CCB)programs is not something that it easily achievable. Local community’s capacity varies from one culture to another. It takes a high level of community participation, in order for it to come to a level where the community members themselves are motivated to participate and contribute to the development of the program. This fully qualitative research involved 15 respondents from the community of Kg. Selai, Bekok in Johor, Malaysia. The result show there are five factors that sustained the ecotourism development based for Orang Asli Community in Kg. Selai, namely, existing CBET development, past CBET development, local community participation in planning stage of tourism, local participation in implementation stage of tourism and participation in nature conservation
Direct sampling of the Susskind-Glogower phase distributions
Coarse-grained phase distributions are introduced that approximate to the
Susskind--Glogower cosine and sine phase distributions. The integral relations
between the phase distributions and the phase-parametrized field-strength
distributions observable in balanced homodyning are derived and the integral
kernels are analyzed. It is shown that the phase distributions can be directly
sampled from the field-strength distributions which offers the possibility of
measuring the Susskind--Glogower cosine and sine phase distributions with
sufficiently well accuracy. Numerical simulations are performed to demonstrate
the applicability of the method.Comment: 10 figures using a4.st
Vacuum state truncation via the quantum Zeno effect
In the context of quantum state engineering we analyze the effect of
observation on nonlinear optical -photon Fock state generation. We show that
it is possible to truncate the vacuum component from an arbitrary photon number
superposition without modifying its remaining parts. In the course of the full
dynamical analysis of the effect of observation, it is also found that the Zeno
and the anti-Zeno effects repeat periodically. We discuss the close
relationship between vacuum state truncation and so-called "interaction-free"
measurement.Comment: 4 pages, 2 figures, LaTeX; TeX errors fixe
Propofol Induction Reduces the Capacity for Neural Information Integration: Implications for the Mechanism of Consciousness and General Anesthesia
The cognitive unbinding paradigm suggests that the synthesis of cognitive information is attenuated by general anesthesia. Here, we investigated the functional organization of brain activities in the conscious and anesthetized states, based on characteristic functional segregation and integration of electroencephalography (EEG). EEG recordings were obtained from 14 subjects undergoing induction of general anesthesia with propofol. We quantified changes in mean information integration capacity in each band of the EEG. After induction with propofol, mean information integration capacity was reduced most prominently in the gamma band of the EEG (p=0.0001). Furthermore, we demonstrate that loss of consciousness is reflected by the breakdown of the spatiotemporal organization of gamma waves. Induction of general anesthesia with propofol reduces the capacity for information integration in the brain. These data directly support the information integration theory of consciousness and the cognitive unbinding paradigm of general anesthesia
Kesan penggunaan koswer multimedia animasi visual terhadap pencapaian pelajar dalam mata pelajaran matematik
Ramai pelajar yang bermasalah dalam topik Pelan dan Dongakan. Ini kerana pelajar sukar untuk membayangkan objek yang tersembunyi melalui proses pengajaran dan pembelajaran (P&P) secara konvensional. Penyelidik telah membangunkan satu koswer multimedia animasi visual dalam topik Pelan dan Dongakan dengan menerapkan kesemua elemen-elemen yang dapat membantu meningkatkan kemahiran visual iaitu elemen animasi, video, audio, grafik dan teks. Seterusnya, kajian kuasi eksperimental ini turut dijalankan bertujuan untuk mengetahui kesan penggunaan koswer multimedia animasi visual terhadap pencapaian pelajar bagi mata pelajaran Matematik di sekolah menengah. Ujian Pra dan Ujian Pos digunakan untuk melihat perbezaan pencapaian yang signifikan selepas menggunakan koswer multimedia animasi visual yang menggunakan teori Kognitif Visual Wiley. Responden yang terlibat dalam kajian ini ialah seramai 40 orang pelajar Tingkatan Lima yang dibahagikan kepada dua kumpulan iaitu kumpulan rawatan dan kumpulan kawalan yang dipilih daripada sebuah sekolah di daerah Batu Pahat, Johor. Hasil analisis menunjukkan peningkatan skor min markah bagi pelajar kumpulan rawatan. Hasil analisis ujian-t (paired-sample-t-test) membuktikan bahawa wujudnya perbezaan skor min markah yang signifikan di antara markah ujian pra dan markah ujian pos bagi kumpulan rawatan. Oleh itu, terdapat perbezaan yang signifikan di antara skor min markah ujian pra dan ujian pos bagi pelajar kumpulan rawatan selepas menggunakan koswer multimedia animasi visual. Manakala instrumen soal selidik yang digunakan untuk melihat tahap penerimaan pelajar selepas menggunakan koswer multimedia animasi visual berdasarkan tiga aspek iaitu aspek isi kandungan, aspek interaksi dan aspek persembahan telah memeperolehi skor min yang tinggi bagi ketiga-tiga aspek tersebut. Dapatan kajian ini menggambarkan penggunaan koswer multimedia animasi visual dapat membantu meningkatkan pencapaian Matematik di dalam bilik darjah terutama yang tidak melibatkan pengiraan
Defect Formation and Kinetics of Atomic Terrace Merging
Pairs of atomic scale terraces on a single crystal metal surface can be made
to merge controllably under suitable conditions to yield steps of double height
and width. We study the effect of various physical parameters on the formation
of defects in a kinetic model of step doubling. We treat this manifestly non-
equilibrium problem by mapping the model onto a 1-D random sequential
adsorption problem and solving this analytically. We also do simulations to
check the validity of our treatment. We find that our treatment effectively
captures the dynamic evolution and the final state of the surface morphology.
We show that the number and nature of the defects formed is controlled by a
single dimensionless parameter . For close to one we show that the
fraction of defects rises linearly with as . We also show that one can arrive at the final state faster and with
fewer defects by changing the parameter with time.Comment: 17 pages, 8 figures. To be submitted to Phys. Rev.
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