Ergodic Interference Alignment

This paper develops a new communication strategy, ergodic interference alignment, for the K-user interference channel with time-varying fading. At any particular time, each receiver will see a superposition of the transmitted signals plus noise. The standard approach to such a scenario results in each transmitter-receiver pair achieving a rate proportional to 1/K its interference-free ergodic capacity. However, given two well-chosen time indices, the channel coefficients from interfering users can be made to exactly cancel. By adding up these two observations, each receiver can obtain its desired signal without any interference. If the channel gains have independent, uniform phases, this technique allows each user to achieve at least 1/2 its interference-free ergodic capacity at any signal-to-noise ratio. Prior interference alignment techniques were only able to attain this performance as the signal-to-noise ratio tended to infinity. Extensions are given for the case where each receiver wants a message from more than one transmitter as well as the "X channel" case (with two receivers) where each transmitter has an independent message for each receiver. Finally, it is shown how to generalize this strategy beyond Gaussian channel models. For a class of finite field interference channels, this approach yields the ergodic capacity region.Comment: 16 pages, 6 figure, To appear in IEEE Transactions on Information Theor

Timescape cosmology with radiation fluid

The timescape cosmology represents a potentially viable alternative to the standard homogeneous cosmology, without the need for dark energy. Although average cosmic evolution in the timescape scenario only differs substantially from that of Friedmann-Lemaitre model at relatively late epochs when the contribution from the energy density of radiation is negligible, a full solution of the Buchert equations to incorporate radiation is necessary to smoothly match parameters to the epoch of photon decoupling and to obtain constraints from cosmic microwave background data. Here we extend the matter-dominated solution found in earlier work to include radiation, providing series solutions at early times and an efficient numerical integration strategy for generating the complete solution. The numerical solution is used to directly calculate the scale of the sound horizon at decoupling, and at the baryon drag epoch. The constraints on these scales from the Planck satellite data yield bounds on the timescape cosmological parameters, which are found to also agree with the best-fit values from a recent analysis of SDSS-II supernova data, while avoiding the problem of a primordial lithium-7 abundance anomaly.Comment: 21 pages, 6 figures; v2: small additions, accepted by Class. Quantum Gra

A full body musculoskeletal model based on flexible multibody simulation approach utilised in bone strain analysis during human locomotion

Load-induced strains applied to bone can stimulate its development and adaptation. In order to quantify the incident strains within the skeleton, in vivo implementation of strain gauges on the surfaces of bone is typically used. However, in vivo strain measurements require invasive methodology that is challenging and limited to certain regions of superficial bones only such as the anterior surface of the tibia. Based on our previous study [Al Nazer et al. (2008) J Biomech. 41:1036&ndash;1043], an alternative numerical approach to analyse in vivo strains based on the flexible multibody simulation approach was proposed. The purpose of this study was to extend the idea of using the flexible multibody approach in the analysis of bone strains during physical activity through integrating the magnetic resonance imaging (MRI) technique within the framework. In order to investigate the reliability and validity of the proposed approach, a three-dimensional full body musculoskeletal model with a flexible tibia was used as a demonstration example. The model was used in a forward dynamics simulation in order to predict the tibial strains during walking on a level exercise. The flexible tibial model was developed using the actual geometry of human tibia, which was obtained from three-dimensional reconstruction of MRI. Motion capture data obtained from walking at constant velocity were used to drive the model during the inverse dynamics simulation in order to teach the muscles to reproduce the motion in the forward dynamics simulation. Based on the agreement between the literature-based in vivo strain measurements and the simulated strain results, it can be concluded that the flexible multibody approach enables reasonable predictions of bone strain in response to dynamic loading. The information obtained from the present approach can be useful in clinical applications including devising exercises to prevent bone fragility or to accelerate fracture healing.<br /

High dose intravenous immunoglobulin in Rh and ABO hemolytic disease of Egyptian neonates

Background: Despite advances made in the use of phototherapy, and in order to avoid sequelae of kernicterus, the treatment of hyperbilirubinemia may require one or several exchange transfusions, an invasive therapy which is not without risk. Intravenous immune globulin treatment in isoimmune hyperbilirubinemia has been shown to be effective, but the response to treatment is variable. Objective: To evaluate effectiveness of high dose Intravenous immune globulin (HD-IVIG) in reducing the need for exchange transfusion, duration of phototherapy and/or hospitalization in neonates with isoimmune hemolytic disease due to Rh or ABO incompatibility. Methods: The study included 116 direct Coombs' test positive neonates delivered at Gynecology and Obstetrics Hospital of Ain Shams University, Cairo, Egypt. They were randomly assigned to receive phototherapy with HD-IVIG in a single dose of 1 gm/kg (60 neonates, intervention group) or phototherapy (56 neonates, control group). Results: Nine neonates in the intervention group (15%) and 23 (41%) in the control group required single exchange transfusion (p&lt; 0.001). Multiple exchange transfusion was indicated in 15 neonates (26.8%) in the control group versus none in the intervention group (p&lt; 0.001). Compared with control group, neonates in the intervention group had shorter mean duration of intensive phototherapy (9.97 versus 35.5 hours, p&lt;0.001) and hospital stay (27.9 versus 103.5 hours, p&lt; 0.001). No adverse effects of HD-IVIG administration were noted. Conclusion: HD-IVIG effectively reduced the requirement for exchange transfusion and duration of phototherapy and hospitalization in isoimmune hemolytic disease of the newborn.Keywords: Hemolytic disease of newborn; hyperbilirubinemia; exchange transfusion; high dose intravenous immunoglobulin

Effect of dapagliflozin on exercise capacity and cardiovascular risk in patients with heart failure

Heart failure (HF) is a serious disorder that affects millions of people worldwide, with a high rate of exercise intolerance, rehospitalization, and death. HF has many underlying causes, including type 2 diabetes mellitus (T2DM), which corresponds with high mortality and short survival among patients with HF. Numerous studies have shown the crucial role of gliflozins, a new generation of blood glucose-lowering medications, in cardiac remodeling, with beneficial impacts on exercise capacity and cardiovascular (CV) mortality, even in non-diabetic individuals. The foundational CV-protective frameworks of these agents are intricate and multifaceted. Dapagliflozin is a new widely used drug and a valuable alternative for patients with T2DM and CV risk factors. Dapagliflozin was approved by the Food and Drug Administration (FDA) in 2019 to lower the risk of HF hospitalization in patients with concurrent T2DM and CV disease or associated risk factors. However, the effects of this new drug on exercise capacity and CV risk still need to be elucidated. The primary objective of this review is to summarize the effect of dapagliflozin on exercise capacity and CV risk in patients with HF

Sickle cell disease and systematic lupus erythematous association in a 14-year-old adolescent female

SCD develops when haemoglobin (HbS) is produced in the body as a result of a mutation occurring in haemoglobin beta chain. SLE is defined as a rare, chronic autoimmune multi-organ manifestation. SCD and SLE rarely coincide in literature due to the limited number of cases and the overlapping of symptoms of both diseases. Majority affecting child bearing age, with a mean of 23-year-old. Articular manifestations like joint pain are common in both diseases. We report a case of female adolescent with sickle cell disease associated with systemic lupus erythematous