1,857 research outputs found
An analysis of short haul airline operating costs
The demand and supply characteristics of short haul air transportation systems are investigated in terms of airline operating costs. Direct, indirect, and ground handling costs are included. Supply models of short haul air transportation systems are constructed
Channel-Optimized Quantum Error Correction
We develop a theory for finding quantum error correction (QEC) procedures
which are optimized for given noise channels. Our theory accounts for
uncertainties in the noise channel, against which our QEC procedures are
robust. We demonstrate via numerical examples that our optimized QEC procedures
always achieve a higher channel fidelity than the standard error correction
method, which is agnostic about the specifics of the channel. This demonstrates
the importance of channel characterization before QEC procedures are applied.
Our main novel finding is that in the setting of a known noise channel the
recovery ancillas are redundant for optimized quantum error correction. We show
this using a general rank minimization heuristic and supporting numerical
calculations. Therefore, one can further improve the fidelity by utilizing all
the available ancillas in the encoding block.Comment: 12 pages, 9 figure
Low proton structure function, using gluon and pseudoscalar meson clouds in the constituent quark framework
The idea of the meson cloud approach in the chiral quark model has been
extended to include gluon cloud in order to achieve the parton densities in the
nucleon, based on the constitute quark framework. The splitting function of the
quark to the quark-meson and quark-gluon at low value are used to obtain
parton densities in the constituent quark. The phenomenological constituent
model is employed to extract the parton distributions in the proton at low
value. Since we have access to the parton densities at low , we are
able to obtain structure function at low value. The result
is in good agreement with available experimental data and some theoretical
models. To confirm the validity of our calculations, the fraction of total
momentum of proton which is carried by gluon at high and also the
Gottfried sum rule are computed. The results are in good agreement with what
are expected.Comment: 13 pages, 3 figure
Integrable sigma models with complex and generalized complex structures
We investigate conditions for having an integrable deformation of the general
sigma model on a manifold with complex structure; such that on a Lie group
these conditions are satisfied (using zeros of Nijenhuis tensor). Then we
extend this formalism to a manifold (and especially a Lie group) with
generalized complex structure.Comment: 19 page
The effects of group play therapy on self-concept among 7 to 11 year-old children suffering from thalassemia major
Background: Children suffering from thalassemia have higher levels of depression and lower levels of self-concept. Objectives: The aim of this study was to determine if group play therapy could significantly increase self-concept among children with thalassemia major ages 7 to 11 years old in teaching hospitals of Golestan province, Iran, in 2012. Patients and Methods: In this randomized, controlled clinical trial, 60 children with thalassemia major were randomly assigned to intervention (30 children) and control (30 children) groups. The intervention included eight 45 to 60 minute sessions during four weeks, during which the intervention group received group play therapy. The control group received no interventions. Selfconcept was measured three times using the Piers-Harris children’s self-concept scale: before, immediately after, and a month after the intervention. Results: For the intervention group, results showed that the mean self-concept score was significantly higher at the second point in time compared to the baseline (P 0.05). Conclusions: The results showed that group play therapy improves self-concept in children suffering from thalassemia major. © 2016, Iranian Red Crescent Medical Journal
Association between vitamin d deficiencies in sarcoidosis with disease activity, course of disease and stages of lung involvements
Background: Despite negative association between 25-hydroxy vitamin D and incidence of many chronic respiratory diseases, this feature was not well studied in sarcoidosis. Current study investigated the association between 25-hydroxy vitamin D deficiency with sarcoidosis chronicity, disease activity, extra-pulmonary skin manifestations, urine calcium level and pulmonary function status in Iranian sarcoidosis patients. Results of this study along with future studies, will supply more effective programs for sarcoidosis treatment. Methods: Eighty sarcoidosis patients in two groups of insufficient serum level and sufficient serum level of 25-hydroxy vitamin D were studied. Course of sarcoidosis was defined as acute and chronic sarcoidosis. Pulmonary function test (PFT) was assessed by spirometry. Skin involvements were defined as biopsy proven skin sarcoidosis. 24-hour urine calcium level was used to specify the disease activity. Stages of lung involvements were obtained by CT-scan and chest X-ray. The statistical analyses were evaluated using Statistical Package for the Social Sciences. Results: A significant negative correlation was obtained between vitamin D deficiency in sarcoidosis patients and disease chronic course and stages two to four of lung involvements. Considering other parameters of the disease and vitamin D deficiency, no significant correlation was detected. Conclusions: In conclusion, results of the current study implies in the role of vitamin 25(OH)D deficiencies in predicting the course of chronic sarcoidosis. Furthermore, it was concluded that vitamin 25(OH)D deficiency can direct pulmonary sarcoidosis toward stage 2–4 of lung involvements
Application of Reduced Differential Transform Method for Solving Nonlinear Reaction-Diffusion-Convection Problems
In this paper, Reduced differential transform method is presented for solving nonlinear reactiondiffusion- convection initial value problems. The methodology with some known techniques shows that the present approach is simple and effective.To show the efficiency of the present method, four interesting examples is given
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