1,823 research outputs found
Electro-absorption of silicene and bilayer graphene quantum dots
We study numerically the optical properties of low-buckled silicene and
AB-stacked bilayer graphene quantum dots subjected to an external electric
field, which is normal to their surface. Within the tight-binding model, the
optical absorption is calculated for quantum dots, of triangular and hexagonal
shapes, with zigzag and armchair edge terminations. We show that in triangular
silicene clusters with zigzag edges a rich and widely tunable infrared
absorption peak structure originates from transitions involving zero energy
states. The edge of absorption in silicene quantum dots undergoes red shift in
the external electric field for triangular clusters, whereas blue shift takes
place for hexagonal ones. In small clusters of bilayer graphene with zigzag
edges the edge of absorption undergoes blue/red shift for triangular/hexagonal
geometry. In armchair clusters of silicene blue shift of the absorption edge
takes place for both cluster shapes, while red shift is inherent for both
shapes of the bilayer graphene quantum dots.Comment: 7 pages, 7 figure
A Government-Binding Analysis of VP Sentential Complements in Egyptian Arabic
This paper examines VP sentential complements in Egyptian Arabic- within a Government and Binding framework. Various types of finite and non-finite sentential complements are identified according to the distribution of the complementizer ?inn 'that' and the elements that fill the complement subject position. It is proposed that Case and Binding parameters are set differently in Egyptian Arabic than in English. In Egyptian Arabic, certain subject NPs are potentially Case-marked by two categories. In these instances the lexical Case-marker prevails, thereby establishing the governing category for the NP, and determining the NP's range of interpretation by the Binding principles
Probing host pathogen cross-talk by transcriptional profiling of both Mycobacterium tuberculosis and infected human dendritic cells and macrophages
This study provides the proof of principle that probing the host and the microbe transcriptomes simultaneously is a valuable means to accessing unique information on host pathogen interactions. Our results also underline the extraordinary plasticity of host cell and pathogen responses to infection, and provide a solid framework to further understand the complex mechanisms involved in immunity to M. tuberculosis and in mycobacterial adaptation to different intracellular environments
Development of exchange lists for M editerranean and H ealthy E ating D iets: implementation in an intervention trial
Background  There has been little research published on the adaptation of diabetic exchange list diet approaches for the design of intervention diets in health research despite their clinical utility. The exchange list approach can provide clear and precise guidance on multiple dietary changes simultaneously. The present study aimed to develop exchange list diets for  M editerranean and  H ealthy  E ating, and to evaluate adherence, dietary intakes and markers of health risks with each counselling approach in 120 subjects at increased risk for developing colon cancer.    Methods  A randomised clinical trial was implemented in the  USA  involving telephone counselling. The  M editerranean diet had 10 dietary goals targeting increases in mono‐unsaturated fats,  n ‐3 fats, whole grains and the amount and variety of fruits and vegetables. The Healthy Eating diet had five dietary goals that were based on the  US H ealthy  P eople 2010 recommendations.    Results  Dietary compliance was similar in both diet arms, with 82–88% of goals being met at 6 months, although subjects took more time to achieve the  M editerranean goals than the  H ealthy  E ating goals. The relatively modest fruit and vegetable goals in the Healthy Eating arm were exceeded, resulting in fruit and vegetable intakes of approximately eight servings per day in each arm after 6 months. A significant ( P  < 0.05) weight loss and a decrease in serum  C ‐reactive protein concentrations were observed in the overweight/obese subgroup of subjects in the  M editerranean arm in the absence of weight loss goals.    Conclusions  Counselling for the  M editerranean diet may be useful for both improving diet quality and for achieving a modest weight loss in overweight or obese individuals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108685/1/jhn12158.pd
Information Security for Audio Steganography Using a Phase Coding Method
The art and science of steganography are dedicated to concealing the presence of a secret message from a third party, such that only the sender and recipient are aware of its content. Various types of media can be used to conceal these communications. When information is hidden in an audio signal, this is referred to as audio steganography. In this paper, two distinct steganography techniques are combined with a multi-level steganography approach: the initial message is embedded in an audio cover at the initial stage, employing, a modified LSB technique, additionally, the second message is embedded in the output from the first level, using a phase coding approach at the second level. A stego audio file is the second level's output containing two audio covers with secret messages. The message is split in multiple ways, with varying proportions between the two levels, in order to investigate how the message's size affects the two procedures used here as well as the levels. The PSNR, MSE, and histogram metrics are used to compare the original and stego audio, in order to assess the effectiveness of the suggested approach. The optimum outcome is achieved when the message is divided in the ratio (1:1). The worst outcome is achieved when the message is divided in the ratio (3:1) 
Large-scale Observations of a Subauroral Polarization Stream by Midlatitude SuperDARN Radars: Instantaneous Longitudinal Velocity Variations
We present simultaneous measurements of flow velocities inside a subauroral polarization stream (SAPS) made by six midlatitude high-frequency SuperDARN radars. The instantaneous observations cover three hours of universal time and six hours of magnetic local time (MLT). From velocity variations across the field-of-view of the radars we infer the local 2D flow direction at three different longitudes. We find that the local flow direction inside the SAPS channel is remarkably constant over the course of the event. The flow speed, however, shows significant temporal and spatial variations. After correcting for the radar look direction we are able to accurately determine the dependence of the SAPS velocity on magnetic local time. We find that the SAPS velocity variation with magnetic local time is best described by an exponential function. The average velocity at 00 MLT was 1.2 km/s and it decreased with a spatial e-folding scale of two hours of MLT toward the dawn sector. We speculate that the longitudinal distribution of pressure gradients in the ring current is responsible for this dependence and find these observations in good agreement with results from ring current models. Using TEC measurements we find that the high westward velocities of the SAPS are - as expected - located in a region of low TEC values, indicating low ionospheric conductivities
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