819 research outputs found

    Certain sufficient conditions for close-to-convexity and starlikeness of multivalent functions

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    By using Jack's lemma, we derive simple sufficient conditions for analytic functions to be multivalent close-to-convex and multivalent starlike

    UTJECAJ DULJINE IGS BAZE NA TOČNOST POZICIONIRANJA GNSS-A

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    Since the establishment of the International GNSS Service (IGS) stations, they have been used as control stations for assigning the Precise point positioning (PPP) positions using one Global Navigation Satellite System (GNSS) receiver, which has increased from day-to-day. There are some factors affecting the accuracy of PPP positioning. This research aims to investigate the relation between the IGS distance and observed field points as well as to attempt to describe that relation mathematically/statically. For the realization of that aim, two field points are fixed inside the Assiut University campus and observed successively for a session of 24 hour observation. The position of each field point is assigned with the help of each one of the available IGS station products. It must be known that these products are found after observations in three files (IGU, IGR, and final IGS), whereas IGU is used directly as real-time data (ultra-rapid), IGR (rapid) is used through (17-41 hours) after observation, and (final IGS) used after 12 – 18 days. Coordinates and point errors of each field points are computed and represented. It has been found that the errors have a positive relation with the available IGS stations distances. The relation between these distances and point positioning errors have been represented and described according to a model. The accuracy of the presented model is (R ≅ .98, x2 ≅ 2.5 × 10-3).Od uspostave postaja Međunarodnoga GNSS servisa (IGS) iz dana u dan povećava se korištenje kontrolnih stanica za dodjelu položaja precizne točke (PPP) pomoću jednoga prijamnika Globalnoga satelitskog navigacijskog sustava (GNSS). Postoje neki čimbenici koji utječu na točnost PPP pozicioniranja. Cilj je ovoga istraživanja istražiti odnos između IGS udaljenosti i promatranih točaka polja te opisati taj odnos matematički i statički. Za realizaciju toga cilja dvije terenske točke fiksirane su unutar kampusa Sveučilišta Assiut i promatrane sukcesivno tijekom sesije promatranja od 24 sata. Položaj svake točke polja dodjeljuje se uz pomoć svakoga od dostupnih proizvoda IGS stanica. Bitno je napomenuti da se ti produkti nalaze u tri datoteke (IGU, IGR i konačni IGS) nakon promatranja, dok se IGU koristi izravno kao podatci u stvarnome vremenu (ultra-rapid), IGR (rapid) kroz 17 – 41 sat nakon promatranja, a konačni IGS nakon 12 – 18 dana. Koordinate i pogreške točaka svake točke polja izračunane su i prikazane. Utvrđeno je da su pogreške u pozitivnom odnosu s dostupnim udaljenostima IGS postaja. Odnos između tih udaljenosti i pogrešaka pozicioniranja točke prikazan je i opisan prema modelu. Točnost je prikazanoga modela R ≅ .98, x2 ≅ 2.5 × 10-3

    Remote Sensing Surveillance of NO<sub>2</sub>, SO<sub>2</sub>, CO, and AOD along the Suez Canal Pre- and Post-COVID-19 Lockdown Periods and during the Blockage

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    This study investigates the impact of the COVID-19 pandemic and the Ever Given ship blockage on the air quality in Suez Canal region. Nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and aerosol optical depth (AOD) were studied, and data were obtained from satellite instruments. The study compared monthly average data for 2020, 2021, and 2022 with a baseline period of 2017–2019 to investigate the pandemic’s effect. The study also analyzed the corresponding period of the canal blockage to identify its impact on air pollution levels. The pandemic had a significant role in decreasing NO2 by 2.5 × 1014 molecule/cm2 and SO2 by 0.05 DU due to reduced car traffic and industrial activities. A reduction in AOD by 20% and CO concentration in the range from 3.5% to 4.7% was reported in early 2020. During the blockage, NO2 and SO2 levels decreased by 14.4% and 66.0%, respectively, while CO and AOD index increased by 12.68% and 51.0%, respectively. The study concludes that the containment measures during the pandemic had a positive impact on the environment, which shows how the reduction in the anthropogenic activities, especially industrial and transportation activities, have improved the air quality. Thus, stricter actions are needed to protect the environment; for example, the transition towards the using of electric vehicle is necessary, which is part of Egypt’s strategy to transition towards a green economy. The government should also adopt a policy to trade carbon emissions reduction certificates to help reduce air pollution.</p

    Intent Profiling and Translation Through Emergent Communication

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    To effectively express and satisfy network application requirements, intent-based network management has emerged as a promising solution. In intent-based methods, users and applications express their intent in a high-level abstract language to the network. Although this abstraction simplifies network operation, it induces many challenges to efficiently express applications' intents and map them to different network capabilities. Therefore, in this work, we propose an AI-based framework for intent profiling and translation. We consider a scenario where applications interacting with the network express their needs for network services in their domain language. The machine-to-machine communication (i.e., between applications and the network) is complex since it requires networks to learn how to understand the domain languages of each application, which is neither practical nor scalable. Instead, a framework based on emergent communication is proposed for intent profiling, in which applications express their abstract quality-of-experience (QoE) intents to the network through emergent communication messages. Subsequently, the network learns how to interpret these communication messages and map them to network capabilities (i.e., slices) to guarantee the requested Quality-of-Service (QoS). Simulation results show that the proposed method outperforms self-learning slicing and other baselines, and achieves a performance close to the perfect knowledge baseline

    Eff ect of preventive and curative interventions on hepatitis C virus transmission in Egypt (ANRS 1211): a modelling study

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    Most hepatitis C virus (HCV) transmission in Egypt is related to medical injections and procedures. To control the spread of HCV, the Egyptian Ministry of Health initiated awareness and education campaigns, strengthened infection control in health-care facilities, and subsidised anti-HCV treatment. We aimed to investigate the effect of these interventions on the spread of HCV by mathematical modelling. Methods We developed a mathematical model of HCV transmission in Zawyat Razin, a typical rural community. Our model assumes that each individual has two distinct types of medical procedures: injections and more invasive medical procedures. To quantify the severity of the spread of HCV, we used the notion of the basic reproduction number R0, a standard threshold parameter signalling whether transmission of an infectious disease is self-sustained and maintains an epidemic. If R0 is greater than 1, HCV is self-sustained; if R0 is 1 or less, HCV transmission is not self-sustained. We investigated whether heterogeneity in the rate of injection or invasive medical procedures is the determinant factor for HCV transmission and whether most iatrogenic transmission is caused by a small group of individuals who receive health-care interventions frequently. We then assessed whether interventions targeted at this group could reduce the spread of HCV. Findings The R0 of the spread of HCV without treatment was 3·54 (95% CI 1·28–6·18), suggesting a self-sustained spread. Furthermore, the present national treatment programme only decreased R0 from 3·54 to 3·03 (95% CI 1·10–5·25). Individuals with high rates of medical injections seem to be responsible for the spread of HCV in Egypt; the R0 of the spread of HCV without treatment would be 0·64 (95% CI 0·41–0·93) if everybody followed the average behaviour. The effect of treatment on HCV transmission is greatly enhanced if treatment is provided a mean of 2·5 years (95% CI 0·1–9·2) after chronic infection and with drug regimens with more than 80% efficacy. With these treatment parameters, preventive and curative interventions targeting individuals with high rates of medical injections might decrease R0 below 1 for treatment coverage lower than 5%. Interpretation Targeting preventive and curative interventions to individuals with high rates of medical injections in Egypt would result in a greater reduction the spread of HCV than would untargeted allocation. Such an approach might prove beneficial in other resource-limited countries with health-care-driven epidemics

    Analysis of sequential active and passive arching in granular soils

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    YesArching in soils has received great attention due to its significance on the soil–underground structure interaction. The state of stress on underground structures as a result of cycles of active and passive arching was neither explored nor systematically assessed. In the present study, comprehensive investigation was carried out to examine: i. the effects of displacement direction to induce active or passive arching, ii. the behaviour of subsequent arching, iii. the effect of magnitude of initial displacement on the formation of arching and iv. the influence of soil height on sequential active and passive arching. The results showed that alternating the displacement of the underground inclusion exacerbated the formation of active and passive arching leading to a substantial reduction in shear resistance and stress redistribution. It is noted that sequentially alternating displacement of the underground inclusion was detrimental to the formation of full active and passive arches irrespective of the burial height

    Certain subclasses of analytic functions with varying arguments

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    In this paper, we introduce new classes VM(β ) and VN(β ) of analytic functions with varying arguments in the open unit disc U = {z ∈ C : |z| &lt;1}. Some properties such as coefficient estimates, extreme points, distortion theorems for functions f (z) belonging to the classes are obtained

    Efficacy and safety of the new generation Watchman FLX device compared to the Watchman 2.5: a systematic review and meta-analysis.

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    The first-generation Watchman 2.5 (W 2.5) presented several limitations, such as challenges in implantation within complex left atrial appendage (LAA) anatomies, higher incidence of peri-device leak, device recapture, and device-related thrombus (DRT). The newer generation Watchman FLX (W-FLX) was introduced with a modified design aiming to overcome these limitations. The purpose of this meta-analysis is to conduct a comparative assessment of the safety and efficacy of the W-FLX and 2.5 devices in clinical practice. The meta-analysis was conducted according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA). Studies were located through a search strategy utilizing PubMed, Cochrane, Google scholar and MEDLINE from inception to March 2023, with a primary objective to compare the safety and efficacy of the W-FLX and W 2.5 devices. After applying the selection criteria, five studies were included in this analysis. The analysis included five studies comprising 54,727 patients. The W-FLX is associated with an increase in procedural success (OR 7.49 [95% CI 1.98-28.26, P = 0.02; = 0%]), and a significant reduction in mortality (OR 0.52 [95% CI 0.51-0.54, P<0.01; = 0%], major bleeding 0.57 [95% CI 0.51-0.64, P<0.01; = 0%]), device embolism (OR 0.35 [95% CI 0.18-0.70, P = 0.02; = 0%]), and pericardial effusion (OR 0.33 [95% CI 0.26-0.41, P<0.01; = 0%]). The rates of DRT and stroke were similar between the two groups. Compared to the W 2.5, the W-FLX was associated with a higher procedural success rate and significantly reduced adverse outcomes including mortality, major bleeding, device embolization, and pericardial effusion. [Abstract copyright: AJCD Copyright © 2023.

    Phytochemical composition and antimicrobial properties of Markhamia platycalyx (Baker) Sprague leaf

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    Purpose: To isolate new antimicrobial agents from the leaves of Markhamia platycalyx (Baker) Sprague and assess their phytochemical characteristics and antimicrobial activity. Methods: Different chromatographic and spectroscopic techniques (NMR and ESI-MS) were applied for the identification of antimicrobial compounds. Agar-well diffusion technique was used for determination of antimicrobial activity. Anti-HCV effects were investigated using VITROS Anti-HCV assay. Results: Eighteen compounds were isolated for the first time from this genus. These were phytol, noctacosanoic acid (OCTA), tormentic acid and β-sitosterol-3-O-(6'-O-heptadecanoyl)-β-Dglucopyranoside. The other compounds were β-sitosterol, ursolic acid (URSA), oleanolic acids, pomolic acid (POMA), 2-epi-tormentic and β-sitosterol-3-O-β-D-glucopyranoside. However, stigmasterol and acteoside, which were seen in previous studies, were also present. Total ethanol extract (TEE) was the most effective against Escherichia coli, with the lowest minimum inhibitory concentration (MIC) of 1.0 µg/mL. Acteoside, URSA and 2-epi-tormentic acid showed the highest antibacterial effect on Pseudomonas aeruginosa while 2-epi-tormentic acid and acteoside produced the least MIC on Candida glabrata. These effects were superior to those produced by standard antibiotics. However, 2-epitormentic acid and β-sitosterol-3-O-β-D-glucopyranoside had no anti-HCV effects. Conclusion: Due to the good antimicrobial properties of Markhamia platycalyx, it is a potential source of new antimicrobial drugs
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