7,143 research outputs found
Broken symmetry, excitons, gapless modes and topological excitations in Trilayer Quantum Hall systems
We study the interlayer coherent incompressible phase in Trilayer Quantum
Hall systems (TLQH) at total filling factor from three
approaches:
Mutual Composite Fermion (MCF), Composite Boson (CB) and wavefunction
approach.
Just like in Bilayer Quantum Hall system, CB approach is superior than
MCF approach in studying TLQH with broken symmetry. The Hall and Hall drag
resistivities are found to be quantized at . Two neutral gapless
modes with linear dispersion relations are identified and the ratio of the two
velocities is close to .
The novel excitation spectra are classified into two classes: Charge neutral
bosonic
2-body bound states and Charge fermionic 3-body bound states.
In general, there are two 2-body Kosterlize-Thouless (KT) transition
temperatures and one 3-body KT transition. The Charge 3-body
fermionic bound states may be the main dissipation source of transport
measurements.
The broken symmetry in terms of algebra is studied. The structure
of excitons and their flowing patterns are given. The coupling between the two
Goldstone modes may lead to the broadening in the zero-bias peak in the
interlayer correlated tunnelings of the TLQH. Several interesting features
unique to TLQH are outlined.
Limitations of the CB approach are also pointed out.Comment: 10 pages, 3 figures, Final version to be published in Phys. Rev.
Onset of Interlayer Phase Coherence in a Bilayer Two-Dimensional Electron System: Effect of Layer Density Imbalance
Tunneling and Coulomb drag are sensitive probes of spontaneous interlayer
phase coherence in bilayer two-dimensional electron systems at total Landau
level filling factor . We find that the phase boundary between the
interlayer phase coherent state and the weakly-coupled compressible phase moves
to larger layer separations as the electron density distribution in the bilayer
is imbalanced. The critical layer separation increases quadratically with layer
density difference.Comment: 4 pages, 3 figure
Android Malware Clustering through Malicious Payload Mining
Clustering has been well studied for desktop malware analysis as an effective
triage method. Conventional similarity-based clustering techniques, however,
cannot be immediately applied to Android malware analysis due to the excessive
use of third-party libraries in Android application development and the
widespread use of repackaging in malware development. We design and implement
an Android malware clustering system through iterative mining of malicious
payload and checking whether malware samples share the same version of
malicious payload. Our system utilizes a hierarchical clustering technique and
an efficient bit-vector format to represent Android apps. Experimental results
demonstrate that our clustering approach achieves precision of 0.90 and recall
of 0.75 for Android Genome malware dataset, and average precision of 0.98 and
recall of 0.96 with respect to manually verified ground-truth.Comment: Proceedings of the 20th International Symposium on Research in
Attacks, Intrusions and Defenses (RAID 2017
Kecelakaan Kerja pada Pekerja Konstruksi Informal di Kelurahan “X” Kota Samarinda
Industri konstruksi menempati peringkat pertama pekerjaan paling berbahaya serta penyumbang tingginya angka kecelakaan kerja baik di dunia maupun di Indonesia. Secara umum kecelakaan kerja disebabkanUnsafe Act dan Unsafe Condition. Penelitian ini bertujuan untuk menganalisis hubungan perilaku tidak aman dan kondisi tidak aman dengan kejadian kecelakaan kerja pada pekerja konstruksi informal di Kelurahan X Samarinda. Penelitian survei analitik dengan pendekatancross sectional telah dilakukan bulan Maret - Mei 2015 pada 40 orangpekerja. Variabel bebas terdiri dari perilaku pekerja tidak aman dan kondisi kerja tidak aman, sementara variabel terikat adalah kecelakaan kerja. Alat ukur penelitian menggunakan kuesioner yang disusun mengacu pada Loss Causation Model dan telah teruji cukup valid dan reliabel. Analisa data menggunakan uji chi square dengan batas kemaknaan α = 0,05. Disimpulkan ada hubungan unsafe act dan unsafe condition dengan kecelakaan kerja dengan p value masing-masing 0.038 dan 0.026. Jenis tindakan tidak aman yang paling banyak dilakukan adalah posisi kerja berbahaya, menjalankan mesin dengan kecepatan yang membahayakan dan serta mengangkat/mengangkut dengan cara yang salah, sedangkan kondisi tidak aman terdiri dari kelayakan dan kerapihan tempat kerja, pelindung/pembatas tidak layak, kondisi APD tidak layak, sistem peringatan yang tidak memadai dan bahaya kebakaran
Geogenomic segregation and temporal trends of human pathogenic Escherichia coli o157:H7, Washington, USA, 2005-2014
The often-noted and persistent increased incidence of Escherichia coli O157:H7 infections in rural areas is not well understood. We used a cohort of E. coli O157:H7 cases reported in Washington, USA, during 2005–2014, along with phylogenomic characterization of the infecting isolates, to identify geographic segregation of and temporal trends in specific phylogenetic lineages of E. coli O157:H7. Kernel estimation and generalized additive models demonstrated that pathogen lineages were spatially segregated during the period of analysis and identified a focus of segregation spanning multiple, predominantly rural, counties for each of the main clinical lineages, Ib, IIa, and IIb. These results suggest the existence of local reservoirs from which humans are infected. We also noted a secular increase in the proportion of lineage IIa and IIb isolates. Spatial segregation by phylogenetic lineage offers the potential to identify local reservoirs and intervene to prevent continued transmission
Animal-assisted pedagogy:human-animal bond, developmental benefits and practical considerations
Abstract. In recent years, animal-assisted pedagogy (AAP) has gained more attention both in the media and in the educational field. Some schools and libraries have seemed to include animals as a common support in the learning process. This has sparked interest also in educational research, and thus the effects of animals as a part of education have been studied more closely. For this reason, we aim to provide insight to AAP with a literature review that explores this topic from the points of view of human-animal bond, the developmental benefits, and the practical considerations related to it. In addition, we aspire to challenge our own views of AAP and discuss how it might be brought into practice.
Based on our research, the human-animal bond is a mutually beneficial relationship that takes place between a human and an animal. Its significance in society and the multitude of benefits it offers, provide a good foundation from which to view AAP. Implementing AAP positively affects the social and emotional competences and motivation of students by the support of the comfort of the animal’s presence, which enables positive experiences and interactions. The animals help to create a safe space that allows the students to feel more confident and secure, and as a result the motivation of learning increases. However, it appears that applying AAP to practice is quite challenging due to the amount of limitations and consideration of bringing an animal into a working environment. For example, allergies, fears and lack of resources may dictate whether it is possible for an educator to practice AAP
Spin Susceptibility and Gap Structure of the Fractional-Statistics Gas
This paper establishes and tests procedures which can determine the electron
energy gap of the high-temperature superconductors using the model
with spinon and holon quasiparticles obeying fractional statistics. A simpler
problem with similar physics, the spin susceptibility spectrum of the spin 1/2
fractional-statistics gas, is studied. Interactions with the density
oscillations of the system substantially decrease the spin gap to a value of
, much less than the mean-field value of
. The lower few Landau levels remain visible, though broadened
and shifted, in the spin susceptibility. As a check of the methods, the
single-particle Green's function of the non-interacting Bose gas viewed in the
fermionic representation, as computed by the same approximation scheme, agrees
well with the exact results. The same mechanism would reduce the gap of the
model without eliminating it.Comment: 35 pages, written in REVTeX, 16 figures available upon request from
[email protected]
Forage Production from Perennial vs. Annual Crop R~ on in Sandy Soils in Egypt
Forage production was studied on newly reclaimed sandy soil in Egypt trom perennial lucerne (Medicago sativa L.) and two annual crop rotations. The cropping systems were: A) lucerne, B) berseem clover (Trifolium alexandrinum L.) in the winter followed by pearl millet (Pennisetum glaucum R. Br. Emend. Stantz.) in the summer and C) triticale (XX Triticosecale Wittm.) (forage cut + grain harvest) in the winter followed by maize (Zea mays L.) (grain + stover) in the summer. Mean annual dry matter yields (t ha-1 ) were 20.65, 26.59 and 27.48 from A, B and C, respectively. However, lucerne provided the most even seasonal forage production
Spin Transition in Strongly Correlated Bilayer Two Dimensional Electron Systems
Using a combination of heat pulse and nuclear magnetic resonance techniques
we demonstrate that the phase boundary separating the interlayer phase coherent
quantum Hall effect at in bilayer electron gases from the weakly
coupled compressible phase depends upon the spin polarization of the nuclei in
the host semiconductor crystal. Our results strongly suggest that, contrary to
the usual assumption, the transition is attended by a change in the electronic
spin polarization.Comment: 4 pages, 3 postscript figur
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