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Göksal Bilgici and Tuncay Deniz Şentürk

Abstract

In this paper, we obtain a closed form for F?i=1k, P?i=1kand J?i=1k for some positive integers k where Fr, Pr and Jr are the rth Fibonacci, Pell and Jacobsthal numbers, respectively. We also give three open problems for the general cases F?i=1n, P?i=1n and J?i=1nfor any arbitrary positive integer n.

Open access

Dewpura A.L. Leelamanie and Chinthani U. Manawardana

Abstract

Application of compost is known to improve the hydraulic characteristics of soils. The objective of this study was to examine the seasonal and short-term effects of solid waste compost amendments on selected hydrophysical properties of soil during dry and rainy seasons and to explore any negative impacts of municipal solid waste compost (MSWC) amendments on soil hydrophysical environment concerning Agriculture in low-country wet zone, Sri Lanka. Eight (T1–T8) MSWC and two (T9, T10) agricultural-based waste compost (AWC) samples were separately applied in the field in triplicates at 10 and 20 Mg ha−1 rates, with a control (T0). Field measurements (initial infiltration rate, I i; steady state infiltration rate, I SS; unsaturated hydraulic conductivity, k; sorptivity, S W) were conducted and samples were collected (0–15 cm depth) for laboratory experiments (water entry value, h we; potential water repellency: measured with water drop penetration time, WDPT) before starting (Measurement I) and in the middle of (Measurement II) the seasonal rainfall (respectively 5 and 10 weeks after the application of compost). The difference in the soil organic matter (SOM) content was not significant between the dry and rainy periods. All the soils were almost non-repellent (WDPT = <1–5 s). The h we of all the samples were negative. In the Measurement I, the I i of the T0 was about 40 cm h−1, while most treatments show comparatively lower values. The I SS, S W, and k of compost amended samples were either statistically similar, or showed significantly lower values compared with T0. It was clear that all the surface hydraulic properties examined in situ (I i, I SS, S W) were higher in the Measurement I (before rainfall) than those observed in the Measurement II (after rainfall). Water potential differences in soils might have affected the surface hydrological properties such as S W. However, water potential differences would not be the reason for weakened I SS and k in the Measurement II. Disruption of aggregates, and other subsequent processes that would take place on the soil surface as well as in the soil matrix, such as particle rearrangements, clogging of pores, might be the reason for the weakened I SS and k in the Measurement II. Considering the overall results of the present study, compost amendments seemed not to improve or accelerate but tend to suppress hydraulic properties of soil. No significant difference was observed between MSWC and AWC considering their effects on soil hydraulic properties. Application of composts can be considered helpful to slower the rapid leaching by decreasing the water movements into and within the soil.

Open access

Najeeb Ur Rehman, Samia Ahmed Al-Riyami, Hidayat Hussain, Amjad Ali, Abdul Latif Khan and Ahmed Al-Harrasi

Abstract

Oxidative stress is often considered detrimental for cellular processes and damaging for the lipid bi-layer. Counteracting such stresses with the aid of nature-based chemical constituents can be an ideal therapeutic approach. The current study aimed to investigate the chemical constituents of resins derived from the well-known Aloe vera and less known Commiphora mukul trees and their effect in mitigating the lipid peroxidation (LPO) process. The bio-guided isolation of bio-active fractions from both resins afforded 20 chemical constituents (17 from A. vera and 3 from C. mukul). These compounds belonged to anthraquinones, anthraquinone glycosides, quinones, coumarins, polypodane-type terpenoids and benzene derivatives. Major chemical constituents of the resins of A. vera and C. mukul were from the classes of quinones and terpenoids. Feroxidin (4, from A. vera) showed slightly higher inhibition (IC 50 = 201.7 ± 0.9 µmol L−1) than myrrhanone C (18, from C. mukul: IC 50 = 210.7 ± 0.0 µmol L−1) and methyl 3-(4-hydroxyphenyl) propionate from A. vera (13, IC 50 = 232.9 ± 0.2 µmol L−1) compared to the other compounds. Structure-activity relationship showed that the existence of hydroxyl, methoxy and ether groups might play a major role in countering oxidative stress. To the best of our knowledge, anti-LPO activities of compounds 14, 14, 18 and 20 are reported for the first time. Such chemical constituents with high anti-lipid peroxidation activity could be helpful in synthesizing candidate drugs.

Open access

Lei Gao, Yaji Wang, Josie Geris, Paul D. Hallett and Xinhua Peng

Abstract

Subtropical regions have clay-rich, weathered soils, and long dry periods followed by intense rainfall that produces large fluctuations in soil water content (SWC) and hydrological behavior. This complicates predictions of spatio-temporal dynamics, as datasets are typically collected at too coarse resolution and observations often represent a duration that is too short to capture temporal stability. The aim of the present study was to gain further insights into the role of temporal sampling scale on the observed temporal stability features of SWC order to aid the design of optimal SWC sampling strategies. This focused on both sampling frequency and total monitoring duration, as previous analyses have not considered both of these sampling aspects simultaneously. We collected relatively high resolution data of SWC (fortnightly over 3.5 years) for various soil depths and under contrasting crops (peanuts and citrus) at the red soil region of southeast China. The dataset was split into a three-year training period and a six-month evaluation period. Altogether 13 sampling frequencies (intervals ranging from 15 to 240 days) and eight monitoring duration periods (between three and 36 months) were derived from the training period to identify temporal stability features and the most time stable location (MTSL). The prediction accuracies of these MTSLs were tested using the independent evaluation data. Results showed that vegetation type did affect the spatio-temporal patterns of SWC, whereby the citrus site exhibited a stronger temporal variation and weaker temporal stability than the peanut site. However, the effects of both sampling frequency and observation duration were more pronounced, irrespective of the role of vegetation type or soil depth. With increasing sampling interval or decreasing monitoring duration, temporal stability of SWC was generally overestimated; by less than 10% when sampling interval increased from every 15 to 240 days and by up to 40% with duration decreasing from 36 to 3 months. Our results suggest that sampling strategies and trade-offs between sampling interval and duration should focus on capturing the main variability in hydro-climatological conditions. For subtropical conditions, we found that sampling once every 45 days over 24 months to be the minimum sampling strategy to ensure errors in SWC temporal stability of less than 10%.

Open access

Tomasz Łukasz Żynda

Abstract

In this paper we will introduce the concept of weighted reproducing kernel of l 2(ℂ) space, in similiar way as it is done in case of weighted reproducing kernel of Bergman space. We will give an explicit formula for it and prove that it depends analytically on weight. In addition, we will show some theorems about dependance of l 2(ℂ) space on weight.

Open access
Open access

Mohamed Akkouchi and Mohamed Amine Ighachane

Abstract

The aim of this paper is to give some refinements to several inequalities, recently etablished, by P.K. Bhandari and S.K. Bissu in [Inequalities via Hölder’s inequality, Scholars Journal of Research in Mathematics and Computer Science, 2 (2018), no. 2, 124–129] for the incomplete gamma function, Polygamma functions, Exponential integral function, Abramowitz function, Hurwitz-Lerch zeta function and for the normalizing constant of the generalized inverse Gaussian distribution and the Remainder of the Binet’s first formula for ln Γ(x).

Open access

Erol Kam, Iskender A. Reyhancan and Recep Biyik

Abstract

Depending on the neutron energy used, neutron radiography can be generally categorized as fast and thermal neutron radiography. Fast neutron radiography (FNR) with neutron energy more than 1 MeV opens up a new range of possibilities for a non-destructive examination when the inspected object is thick or dense. Other traditional techniques, such as X-ray, gamma ray and thermal neutron radiography, do not meet penetration capabilities of FNR in this area. Because of these distinctive features, this technique is used in different industrial applications such as security (cargo investigation for contraband such as narcotics, explosives and illicit drugs), gas/liquid flow and mixing and radiography and tomography of encapsulated heavy shielded low Z compound materials. The FNR images are produced directly during exposure as neutrons create recoil protons, which activate a scintillator screen, allowing images to be collected with a computer-controlled charge-coupled device camera. Finally, the picture can be saved on a computer for image processing. The aim of this research was to set up a portable FN R system and to test it for use in non-destructive testing of different composite materials. Experiments were carried out by using a fast portative neutron generator Thermo Scientific MP 320.

Open access

Faisal Al-Otaibi

Abstract

There are several limited approaches to treat epilepsy in hospitals, for example, using medicines, surgery, electrical stimulation and dietary interventions. Despite the availability of all these new and old approaches, seizure is particularly difficult to manage. The quest for new antiepileptic molecules with more specificity and less CNS toxicity continues for medicinal chemists until a new and ideal drug arrives. This review covers new antiseizure molecules of different chemical classes, the exact mode of action of which is still unidentified. Newer agents include sulfonamides, thiadiazoles, semi- and thiosemicarbazones, pyrrolidine-2,5-diones, imidazoles, benzothiazoles and amino acid deriva tives. These new chemical entities can be useful for the design and development of forthcoming antiseizure agents.

Open access

Anetta Szynal-Liana and Iwona Włoch

Abstract

The hybrid numbers are generalization of complex, hyperbolic and dual numbers. In this paper we consider special kinds of hybrid numbers, namely the Jacobsthal and the Jacobsthal-Lucas hybrid numbers and we give some their properties.