3,995 research outputs found
Two Dimensional Spin-Polarized Electron Gas at the Oxide Interfaces
The formation of a novel spin-polarized 2D electron gas at the LaMnO
monolayer embedded in SrMnO is predicted from the first-principles
density-functional calculations. The La (d) electrons become confined in the
direction normal to the interface in the potential well of the La layer,
serving as a positively-charged layer of electron donors. These electrons
mediate a ferromagnetic alignment of the Mn t spins near the interface
via the Anderson-Hasegawa double exchange and become, in turn, spin-polarized
due to the internal magnetic fields of the Mn moments.Comment: 5 pages, 6 figure
Strain and Electric Field Modulation of the Electronic Structure of Bilayer Graphene
We study how the electronic structure of the bilayer graphene (BLG) is
changed by electric field and strain from {\it ab initio} density-functional
calculations using the LMTO and the LAPW methods. Both hexagonal and Bernal
stacked structures are considered. The BLG is a zero-gap semiconductor like the
isolated layer of graphene. We find that while strain alone does not produce a
gap in the BLG, an electric field does so in the Bernal structure but not in
the hexagonal structure. The topology of the bands leads to Dirac circles with
linear dispersion in the case of the hexagonally stacked BLG due to the
interpenetration of the Dirac cones, while for the Bernal stacking, the
dispersion is quadratic. The size of the Dirac circle increases with the
applied electric field, leading to an interesting way of controlling the Fermi
surface. The external electric field is screened due to polarization charges
between the layers, leading to a reduced size of the band gap and the Dirac
circle. The screening is substantial in both cases and diverges for the Bernal
structure for small fields as has been noted by earlier authors. As a biproduct
of this work, we present the tight-binding parameters for the free-standing
single layer graphene as obtained by fitting to the density-functional bands,
both with and without the slope constraint for the Dirac cone.Comment: 7 pages, 7 figure
Designing Verbal Message And Visual Media Of Quick Chicken
Quick Chicken currently exists on more than 8 islands, more than 17 provinces, more than 220 outlets. Compared to similar fried chicken outlets, Quick Chicken outlet designs are more attractive because they use the concept of selling in containers. The advantages of Quick Chicken are offering a menu that is a combination of traditional and western, in addition, Quick Chicken also offers larger pieces of chicken than its competitors, namely Hisana and Sabana. Currently Quick Chicken is experiencing a decline in sales. This happens because the promotion done has not been able to make the target audience aware and loyal. The question research is how to design verbal message and visual media as the solustion for the problem above. Semantics is used to define the verbal message, while advertising theory is used as the the grand theory of visual media. The methode used is qualitative descriptif. The result is as the recommendation design of the verbal message and visual media as the solution for the problem using AISAS. The conclusion is with the design of Quick Chicken promotion, it is hoped that being able to be a solution to identified problems, and it can also be a reference for similar problems as well.
Key Words: Semantics, verbal message, Visual Media, Quick Chicke
Networking frictions in venture capital, and the gender gap in entrepreneurship
We find that male participants in Harvard Business School’s New Venture Competition who were randomly exposed to more VC investors on their panel were substantially more likely to start a VC-backed startup post-graduation, indicating that access to investors impacts fundraising independent of the quality of ideas. However, female participants experience no benefit from exposure to male or female VCs, which appears related to a reduced propensity to reach out to VCs to whom they were exposed. Our results therefore also demonstrate gender-based differences in the degree to which increased exposure to investors can address networking frictions in venture capital
Time for pulse traversal through slabs of dispersive and negative (, ) materials
The traversal times for an electromagnetic pulse traversing a slab of
dispersive and dissipative material with negative dielectric permittivity
() and magnetic permeability () have been calculated by using
the average flow of electromagnetic energy in the medium. The effects of
bandwidth of the pulse and dissipation in the medium have been investigated.
While both large bandwidth and large dissipation have similar effects in
smoothening out the resonant features that appear due to Fabry-P\'{e}rot
resonances, large dissipation can result in very small or even negative
traversal times near the resonant frequencies. We have also investigated the
traversal times and Wigner delay times for obliquely incident pulses and
evanescent pulses. The coupling to slab plasmon polariton modes in frequency
ranges with negative or is shown to result in large traversal
times at the resonant conditions. We also find that the group velocity mainly
contributes to the delay times for pulse propagating across a slab with n=-1.
We have checked that the traversal times are positive and subluminal for pulses
with sufficiently large bandwidths.Comment: 9 pages, 9 figures, Submitted to Phys. Rev.
Monthly Pattern and Distribution of Births in a Teaching Institution of Northern India
Background: Seasonality in frequency of birth is a world-wide phenomenon that reflect behavioral and biological determinant of reproduction. Aim: To assess pattern of birth occurring in a medical college hospital according to calendar months. Materials and Methods: Log books of delivery room were retrieved and all singleton live births occurring in each month for the calendar years 2002-2009 (8-year) was extracted. Data collection was carried out by the investigators during the period February-April 2010 and data management using software statistical package. Analysis was carried out by calculating average birth per month for the period under study and standard index as well as quarter-wise details was also tabulated. Result: It was observed that there was a progressive rise in total number of births occurring in the hospital from 5840 (avg. 486.66/month) from the year 2002 to 8205 (avg. 683.75/month) in 2009. Maximum birth occurred during the months of August (avg. 774/month) followed by September (avg. 735/month) and October (avg. 705/month) respectively and least in the month of April (avg. 445/month) with a P<0.05. Quarter (q) wise distribution showed maximum birth during q3 (July-September=30%) followed by q4 (October- December=27%), q2 (April-June=22%) and q1 (January-March=21%) respectively. Conclusion: It can be concluded that peak birth in the months of August-September-October as observed in present study implying that there is increased conception during the winter months of December-January-February. Within study limitations, findings may facilitate advocacy, counseling, planning and delivery of family welfare service in a more efficient and effective manner particularly related to mobilization of human resource, inventory control, logistics, streamlining family planning services at institutional and community level keeping in mind the monthly pattern of hospital deliveries. Keywords: Behavior, communication, conception, delivery, demography, family planning, fertility, human resource, months, pattern, reproduction, seasonality, tim
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