Asymptotically-Optimal Incentive-Based En-Route Caching Scheme

Content caching at intermediate nodes is a very effective way to optimize the operations of Computer networks, so that future requests can be served without going back to the origin of the content. Several caching techniques have been proposed since the emergence of the concept, including techniques that require major changes to the Internet architecture such as Content Centric Networking. Few of these techniques consider providing caching incentives for the nodes or quality of service guarantees for content owners. In this work, we present a low complexity, distributed, and online algorithm for making caching decisions based on content popularity, while taking into account the aforementioned issues. Our algorithm performs en-route caching. Therefore, it can be integrated with the current TCP/IP model. In order to measure the performance of any online caching algorithm, we define the competitive ratio as the ratio of the performance of the online algorithm in terms of traffic savings to the performance of the optimal offline algorithm that has a complete knowledge of the future. We show that under our settings, no online algorithm can achieve a better competitive ratio than $\Omega(\log n)$, where $n$ is the number of nodes in the network. Furthermore, we show that under realistic scenarios, our algorithm has an asymptotically optimal competitive ratio in terms of the number of nodes in the network. We also study an extension to the basic algorithm and show its effectiveness through extensive simulations

Left atrial and left atrial appendage functional recovery after cardioversion in patients with recent atrial fibrillation: Serial echocardiographic study

Background: The aim of this study is to point out timing of left atrium and its appendage functional recovery after cardioversion (CV) in recent onset atrial fibrillation (AF). Methods: Fifty patients; 27 within 48-h (group I) and 23 after 48-h (group II), of AF onset, who had successful CV underwent transthoracic echocardiography (TTE), before and im­mediately after CV, then 15, 30 and 90 days later. Transesophageal echocardiography (TEE) was performed for group II before and for all patients immediately after CV and 1 month later. Mitral peak A velocity and left atrial (LA) reversal (Ar) velocity, tissue Doppler imaging (TDI) of septal mitral annular velocity (A1) and LA free wall velocity (A3) were recorded. Absence or peak A velocity < 50 cm/s was taken as a cut off value for atrial stunning. Intra-atrial conduction time (IACT) was measured. LA appendage late emptying (LAALE) velocity was measured by TEE-pulsed TDI of LA appendage. Results: Post CV, all group II and 34% of group I experienced stunning. In both groups, peak A, Ar, A1, A3 and LAALE velocities increased (p = 0.000), while IACT decreased (p = 0.000) progressively over time. Partial recovery occurred after 15 and 30 days, while full recovery occurred 30 and 90 days post CV in groups I and II, respectively. IACT1 and IACT2 correlated with LA diameter (r = 0.2778 and r = 0.227, respectively, p < 0.01). Conclusions: Stunning and functional recovery of the LA and its appendage are strongly determined by the duration being in AF. Serial IACT by TDI was a good new parameter for detection of functional recovery of LA and LA appendage

Recycling of Chicken Egg Shells into Nanopowder: Synthesis, and its Properties

تم تحسين الموارد غير التقليدية من الكالسيوم (Ca+2) للطيور والأحياء المائية والحيوانات المحلية. تم التخطيط لهذا البحث لتحديد أكثر أنواع كربونات الكالسيوم تعددًا (CaCO3) التي تحدث في نوعي قشر بيض الدجاج (النوع المحلي والنوع المستورد). في هذا البحث ، تمت العمل على التحليل المقارن لمحتوى كربونات الكالسيوم) (CaCO3 لقشر البيض من السلالة المحلية والمستوردة عبر اجراء تحليل المجهر الإلكتروني لمسح الانبعاث الميداني (FESEM) ، ومجهر الإرسال الإلكتروني (TEM) ، والتحليل الطيفي للأشعة تحت الحمراء (FTIR) و تحليل حيود الشعاع للمسحوق (PXRD). أظهرت النتائج أن قشر بيض الدجاج الأصلي والمستورد يشتمل على شكل الكالسيت الذي له شكل  بين المعيني والكروي مع توزيع مسام مميز في السطح وحجم تبلور (31) نانومتر لقشر بيض الدجاج المحلي و (32) نانومتر لقشر بيض الدجاج المستورد على التوالي. يوجز الباحثون نتائجهم بأن قشر بيض الدجاج المحلي والمستورد يحتوي على أعلى موارد كربونات الكالسيوم (CaCO3).Increase in unconventional resources of calcium (Ca+2) for fowls, aquaculture and native animals was improved. This work was planned to define the most polymorph of calcium carbonate (CaCO3) that take place in the two types of chicken eggshells (local and imported type). In this research, the comparative analysis of calcium carbonate (CaCO3) content was approved for nominated eggshells of native strain and imported chicken via Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscope (TEM), Fourier-Transform Infrared Spectroscopy (FTIR) and Powder X-Ray Diffraction (PXRD) analysis. The results demonstrate that native and imported chicken eggshells comprise calcite morph that had shape between rhombohedral and spherical with distinguished pores distribution in the surface and crystallization size (31) nanometer for local chicken eggshells and (32) nanometer for import chicken eggshells respectively. The authors brief their results that local and import chicken eggshells had the top resources of calcium carbonate (CaCO3)

The Effect of Leverage on Financial Health of the Firms: A Study from Cement Industry of Pakistan

This research paper has tried to measure the relationship between leverage and profitability of firms in the cement industry of Pakistan. Debt to equity is used to measure the leverage of the companies in the cement industry in Pakistan. Short term debt to equity (STD/E) and long term debt to equity (LTD/E) are considered as leverage variables .Return on equity (ROE) and return on assets (ROA) are used to measure the financial performance of the companies. For this research paper 10 cement companies are considered, listed in the Karachi Stock Exchange during the time period 2008-2012. To measure the relationship between leverage and profitability of firms in the cement industry of Pakistan regression model and descriptive statistics have been used. Our results found negative and significant relationship between leverage and profitability of the firm. Keywords: Leverage, Profitability, Cement industry, Capital Structur

Optimization of Key Parameters Towards High Performance Perovskite Solar Cells

Here, we report important findings regarding underestimated parameters for the synthesis and fabrication of high-performance perovskite solar cells. These parameters include the effect of Fluorine-doped Tin Oxide (FTO) etching, FTO cleaning, the number of compact TiO 2 (c-TiO 2 ) layer, the number of mesoporous TiO 2 (m-TiO 2 ) layers and the aging time before Ag deposition. Our results demonstrated that etching of FTO substrate with Zn/HCl is an essential step and has a major effect on the solar cell's open circuit voltage (Voc), fill factor (FF) and power conversion efficiency (PCE). Furthermore, we demonstrate new and improved protocols for the complete cleaning of FTO substrates. Despite the use of sonication and plasma etching in previous cleaning techniques, SEM images clearly show black clouds in the samples, which may be due to residual Zn particles in the FTO grooves. Thus, a soft toothbrush was used with detergent before sonication to detach the remaining Zn particles. In addition, the optimum number of spin coated layers of compact and mesoporous TiO 2 precursors was investigated. We found that one mesoporous and two compact TiO 2 layers were required to obtain a homogenous pinhole-free compact layer. Consequently, we demonstrate that using these optimized device fabrication procedures, a high efficiency of 17.96% for 6 mol% Co 3+ -doped TiO 2 solar cells can be obtained in comparison to 16.98% for pristine TiO 2 -based cells. Such cells are particularly important for wearable applications that require a small area and a high energy

In situ degradability of soyabean meal treated with Acacia saligna and Atriplex halimus extracts in sheep

The effects of Acacia saligna (AC) and Atriplex halimus (AT) extracts were evaluated on ruminal soyabean meal (SBM) degradability using the nylon bag technique. Samples of SBM were treated with 0, 4, or 8 g of AC or AT extracts per 100 g SBM. Bags were incubated in two cannulated sheep for 2, 4, 6, 8, 12, 24, and 48 h. The chemical constituents (CCs) of extracts was determined using GC-MS. Rate and potential degradability of dry matter (DM) were decreased (P=0.015) to a greater extent than N degradability (P=0.145) with AC and AT doses. DM and N degradation were decreased (P<0.05) by 15% and 29%; 24% and 47% with AC, and 21% and 29%; 23% and 37% with AT at 4% and 8% for DM and N, respectively. The data suggest the possibility of using these extracts as feed additives to reduce ruminal degradability of SBM in ruminant diets