An empirical analysis of smart contracts: platforms, applications, and design patterns

Smart contracts are computer programs that can be consistently executed by a network of mutually distrusting nodes, without the arbitration of a trusted authority. Because of their resilience to tampering, smart contracts are appealing in many scenarios, especially in those which require transfers of money to respect certain agreed rules (like in financial services and in games). Over the last few years many platforms for smart contracts have been proposed, and some of them have been actually implemented and used. We study how the notion of smart contract is interpreted in some of these platforms. Focussing on the two most widespread ones, Bitcoin and Ethereum, we quantify the usage of smart contracts in relation to their application domain. We also analyse the most common programming patterns in Ethereum, where the source code of smart contracts is available.Comment: WTSC 201

Digitally: Piloting offline payments for phones

Mobile payments support a range of services in many less developed countries including everyday payments, migrant remittances, credit, tax collection, and welfare benefits. These services depend entirely on the mobile phone network as their carrier, so they stop where the network does. This leaves millions of the very poorest people stranded - people living in remote areas where there is little to no network service. It also leaves urban users at the mercy of network congestion. We developed a prototype system, DigiTally, which lets users make offline payments by copying short strings of digits from one mobile handset to another. Offline payments are already used for electricity (both in prepayment meters and pay-as-you-go solar); can we extend them into a general-purpose payment system, to increase service resilience in the face of network congestion or outage, and provide service to currently excluded areas? We report the results of a preliminary study with an early prototype of DigiTally, tested on participants from a university in Nairobi (Kenya). The code-sharing process presented a possible usability challenge. To explore this and other aspects of an early prototype, DigiTally was introduced to Kenyan participants in order to resolve any major issues before a later field trial. We discuss the lessons learned from our field visits and initial evaluation; we hope that this contribution is helpful for researchers and policy makers interested in mobile payments and financial inclusion. We also present our findings and observations. We found that, although offline payments involve copying codes in both directions between the payer's phone and the payee's, the extra workload was acceptable to most users.This work was supported by a grant from the Bill & Melinda Gates Foundatio

Studying the Physical Properties of Hma with Recycled Aggregate Subjected to Moisture

تصنع الخلطات الاسفلتية الحارة HMA  من مواد معينة ذات حساسية لوجود المياه في التبليط الاسفلتي الذي يمنع العجينة من الالتصاق بالركام . ولكون العجينة هي الغراء الذي تمسك الخلطة مع بعضها , لذا فان  الفشل الانشائي المتوقع بالتبليط سيكون سريع من جراء ضعف الالتصاق بين العجينة والركام او ما يسمى بالانفصال  stripping الذي يوجب استخدام مضافات معينة لتجنبه ك الجير المطفأ او أي مواد كيمياوية مضادة للانفصال anti-stripping.  وعليه اجريت هذه الدراسة لفحص وقياس مقاومة انواع مختلفة من الخلطات الاسفلتية ذات ركام معاد تدويره عند تعريضها لفترات تشبع بالرطوبة بالإضافة الى فحص مغزى استخدام المضادات للانفصال كمضافات . تم  في هذا البحث تعريض ثلاثة انواع من الخلطات الاسفلتية , واحدة 60% من ركامها معاد من خلطة اسفلتية واخرى 60% من ركامها معاد من خلطة خرسانية  والخلطة الثالثة مستخدمة الشمع كمضاف وبنسبة 10% من وزن الاسفلت , للتغريق بالماء بمدد مختلفة تمثلت ب( 3, 7, 15, 28 ) يوم , كما  اجريت فحوصات مختبرية متعددة عليها ومقارنة النتائج مع خلطة اسفلتية قياسية عرضت لنفس الظروف . تم اجراء( فحص مارشال للثبات والزحف ), الكثافة , مقاومة الشد الغير مباشرة , مقاومة الانضغاط ، فحص التحسس للحرارة , فحص قوة المرونة . كان التحري موفقا حيث اعطى نتائج قيمة تبين تحسن الخلطة الاسفلتية في مقاومتها للرطوبة عند استخدام ركام معاد من خلطات سابقة واثبات دور الشمع الفعال في زيادة تللك المقاومة وتحسين خواص الخلطة الاسفلتية.As being exposed to water that exists on asphalt road, HMA that is created by utilizing a certain resources may require to be made strong due to the capability of that water to stop the covering to be attached to the aggregate, consequently, asphalt road layers will not be held jointly, this will have a negative influence on the asphalt that will be damaged quickly. Such phenomenon is known as "the erosion", which requires to be dealt with by, for example, improving asphalt layers by means of specific resources that assist in existence of water. Different ways in this work are employed to calculate the strength of various mixes via using used aggregate that is exposed to  saturation times, similarly, the importance of exploiting the anti-stripping as chemical addition is determined. Three kinds of HMA were exposed in the current study, 60% of the first kind were made of used aggregate taking from crushed pavement, and 60% of the second kind were taking from using aggregate that is part of concrete mix, while the third mixture has 10% of wax used as an addition by pavement weight. These mixtures were soaked in water bath of 25o C for various intervals of time that are (3, 7, 15, 28) days. Many investigations examinations had been as well executed, and then the outcomes were contrasted against standard pavement blend subjected to similar circumstances. Number of examinations were adopted in this study, these are (Marshall Stability and flow), mass thickness, roundabout elasticity, compressive quality, affectability to temperature, flexible modulus. The study achieved a good success as it makes important outcomes, the enhanced pavement showed strength against moisture damage while taking advantage of used aggregate of preceding blends, on other hand, the wax has affective role in raising these strengths in addition to develop the characteristics of HMA.&nbsp

The Influence of Hyper-Alkaline Leachate on a Generic Host Rock Composition for a Nuclear Waste Repository: Experimental Assessment and Modelling of Novel Variable Porosity and Surface Area

Deep geological disposal is the preferred solution for long-term storage of radioactive waste in many countries. In a deep repository, cementitious materials are widely used in the structure and buffer/backfill of the repository for the stabilisation of the hazardous materials. The cement acts as a physical barrier and also contributes chemically to waste containment by buffering the groundwater to a high pH, limiting the solubility of many radionuclides. This paper describes an experimental and modelling study which evaluates the geochemical interaction between young cement leachate (YCL, pH = 13) and a generic hard rock (in this case Hollington sandstone, representing a ‘hard’ host rock) during permeation with the leachate, as it drives mineralogical changes in the system. One-dimensional reactive transport was modelled using a mixing cell approach within the PHREEQC geochemical code to identify the essential parameters and understand and scale up the effect of variations in these parameters on the observed geochemical processes. This study also focused on the effects of variable porosity, reactive surface area and pore volume on improving the modelling of rock alteration in the system compared to conventional models that assume constant values for these properties. The numerical results showed that the interaction between the injected hyper-alkaline leachate and the sandstone sample results in a series of mineralogical reactions. The main processes were the dissolution of quartz, kaolinite and k-feldspar which was coupled with the precipitation of calcium silicate hydrate gel and tobermorite-14A (C–S–H), prehnite (hydrated silicate), saponite-Mg (smectite clay) and mesolite (Na–Ca zeolite). The simulation showed that the overall porosity of the system increased as primary minerals dissolve and no stable precipitation of the secondary C–S–H /C–A–S–H phases was predicted. The variable porosity scenario provides a better fitting to experimental data and more detailed trends of chemistry change within the column. The time and the number of moles of precipitated secondary phases were also improved which was related to greater exposure surface area of the minerals in the sandstone sample to the YCL

Effectiveness of raw bacteriocin produced from lactic acid bacteria on biofilm of methicillin-resistant Staphylococcus aureus

Background and Aim: Probiotics are proven beneficial to health since they enhance immunity against dangerous pathogens and increase resistance to illness. Bacteriocin produced by lactic acid bacteria (LAB), demonstrates a broad inhibitory spectrum and therapeutic potential. This study aimed to isolate LAB-producing bacteriocin and investigate the effect of crude bacteriocin on biofilm from methicillin-resistant Staphylococcus aureus (MRSA). Materials and Methods: This study used randomly collected 80 white soft local cheeses (40 each from cows and sheep) from different supermarkets in Basrah Province. The obtained samples were cultured and the bacterial suspension of S. aureus was prepared at 1.5 × 108 cells/mL. The crude bacteriocin extracted from LAB was obtained, and the tube was dried and inverted to detect the biofilm loss at the bottom. Results: There were 67 (83.75%) LAB isolates. Among 40 milk samples collected directly and indirectly, there were 36 (83.33%). Staphylococcus aureus isolates based on conventional bacteriological analysis and biochemical tests. Molecular testing was conducted to identify LAB and MRSA. Depending on genotypic results, the effect of white soft local cheese (cows and sheep) and the amplification results of the 16S rRNA gene were detected in 46 LAB isolates from white soft local cheese from cows and sheep. Based on the molecular identification of the mecA, results on Staphylococcus determined that only 2 of 36 isolates of S. aureus carried the mecA. Moreover, there were 26 (86.66%) isolates (MRSA) from samples of raw milk from local markets and subclinical mastitis in cows. The ability of LAB isolates was tested. The effects of bacteriocin production on preventing biofilm growth and formation were investigated. Results demonstrated that bacteriocin has high activity. Microtiter plates applied to investigate the ability of S. aureus to produce biofilms revealed that all isolates were either weak or moderate biofilm producers, with neither non-biofilm nor strong biofilm producers found among the tested isolates. Conclusion: Lactic acid bacteria demonstrate a high ability to produce bacteriocin. Crude bacteriocin from LAB has a restrictive effect on biofilms produced by MRSA; thus, it can be used to reduce the pathogenicity of this bacterium

Soft Tissue Pathology Detected By Ultrasound Seem To Be Risk Factors for Painful Flare in Osteoarthritic Knee

BACKGROUND: To our knowledge, the importance of US findings, pain (brief pain inventory (BPI)) and disability in osteoarthritic knee (OA) pain patients remain uncertain. AIM: The objectives are to evaluate the correlation of US findings, pain (brief pain inventory (BPI)) and disability in OA pain patients. MATERIALS AND METHODS: Eighty - three patients with OA knee were divided into two groups. The first group was OA as symptomatic knee group and the second group was an asymptomatic control group. The maximum sagittal height of synovial fluid in 12 scans at 0, 30, 60 and 90 degrees flexion knee in 3 major recesses were measured. RESULTS: There were a significant positive correlation between BPI Pain severity index, or BPI function interference index and a maximum height of effusion at 30-degree flexion angle in a supra-patellar recess in painful symptomatic knees. But, there was a significant negative correlation between BPI Pain severity index, and BPI function interference index and cartilage thickness in painful symptomatic knees. CONCLUSION: The increase of maximum height of synovial effusion at different angles of knee and decrease of cartilage thickness associated with pain and disability in OA pain patients and are being predictors for pain severity and disability in OA pain patients

Relationship between Gait Parameters and Postural Stability in Early and Late Parkinson's Disease and Visual Feedback-Based Balance Training Effects

BACKGROUND: Gait disorders or postural instability has been done before. However, lack of reviews has addressed the relation between gait and postural stability in Parkinson's disease (PD).AIM: The aim was to evaluate the relation between gait parameters and postural stability in early and late stages of PD.MATERIALS AND METHODS: The forty-one idiopathic PD patients were divided into two groups into a group (A) considered as early PD and group (B) considered as late ambulant PD. They were evaluated for postural stability by computerised dynamic posturography (CDP) device and gait analysis using an 8 m-camera Vicon 612 data capturing system set.RESULTS: There was a statistically significant improvement of composite equilibrium score, the composite latency of motor response, walking speed and cadence after treatment as compared to before training (p < 0.05) in early PD. However, in the late PD, there was a non-significant change of previous parameters after treatment as compared to before training (p > 0.05).There was a significant correlation between UPDRS motor part score, walking speed and composite equilibrium score after training in early PD (p > 0.05).CONCLUSIONS: Both gait analysis and CDP are important quantitative assessment tools of gait and posture instability

Ultrasonographic Enthesopathy and Disease Activity in Psoriatic Arthritis

BACKGROUND: To our knowledge, the correlation between ultrasonographic enthesopathy and severity in psoriatic arthritis (PsA) has been done before. However, the correlation between ultrasonography of enthesopathy and the Psoriatic Arthritis Disease Activity Score (PASDAS) have not been done.AIM: To compare the results of ultrasonographic enthesopathy of foot and PASDAS in PsA.MATERIALS AND METHODS: A total of 65 PsA patients were involved and divided into two groups. The first group of 35 active PsA and the second group of 30 ages and sex matched inactive PsA as a control group were recruited in this study. Both groups were evaluated by examination, radiological findings and ultrasonography.RESULTS: Of 70 entheses in 35 active PsA patients, the most entheseal abnormalities were tender plantar fascia (18.5%), tender Achilles tendon (37.8%). PASDAS was a direct highly significant correlated with plantar fascia and Achilles tendon thickness in in active PsA (r = 0.823 and r = 0.796, p < 0.001 respectively).CONCLUSION: Musculoskeletal US is an accurate and low-cost method for assessment of enthesopathy with significant correlation to disease activities in psoriatic arthritis

Workplace Spirituality and Its Role in Achieving Self-empowerment

Workplace spirituality is a construct widely discussed over the past few decades and it is a much-disputed inquiry field which is gaining the interest of practitioners and scholars. Some clarifications regarding concepts and definitions are necessary in order to structure and direct the current debate , This study aims to study the role of workplace spirituality where many researchers have emphasized on its importance for achieving self-empowerment among employees . For that purpose , a total of 200 Questionnaires were distributed to respondents working at the Shrine of Imam Ali ( Peace be upon him ) , out of which 185 forms that were properly filled were used for analysis . Research data was collected and analyzed through statistical analysis by employing a package of (SPSS). The findings show that workplace spirituality has a tremendous positive effect of workplace spirituality in self-empowering the employees. Furthermore , the findings of the study will present a significant contribution to literature through creating awareness concerning subject not only for organization management but also for its member