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Effects of Hydrogels on Soil Moisture and Growth of <i>Cajanus cajan</i>in Semi Arid Zone of Kongelai, West Pokot County

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Open Journal of Forestry 2014年第1期4卷 34-37页

作者： Cheruiyot Gilbert Sirmah Peter Ng’etich Wilson Mengich Edward Mburu Francis kimaiyo sylvester Bett Erick School of Agriculture University of Eldoret Eldoret Kenya School of Natural Resource Management University of Eldoret Eldoret Kenya School of Natural Resource Management University of Eldoret Eldoret Kenya Kenya Forestry Research Institute Londiani Kenya School of Science University of Eldoret Eldoret Kenya

Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajanus cajan in arid and semi-arid lands were carried out. Seedlings of C. cajan were established both in the nursery and in the field with and without hydrogels. In the field, three replications were used with three levels of hydrogels concentration (7 g, 11 g, and 15 g). Control seedlings were established in soils without hydrogels. In the nursery, root collar diameters and heights were measured every two weeks up to eight weeks. Seedlings established without hydrogels in the nursery were transplanted into field soils with none, 7 g, 11 g and 15 g of hydrogels. Root collar diameters and heights were again measured every month for three months. In addition, soil was collected randomly once every month from the base of each seedling and analyzed for soil moisture using standard laboratory procedures. All data were subjected to analysis of variance. The results show that growth in both the height and root collar diameter of the species was significantly different at the three levels of hydrogels. This suggests that use of hydrogels retards plant growth in nursery soils but improves growth in the field. Hydrogels increased soil moisture volume from 8.3% to 10% in H15g level of hydrogels under C. cajan after transplanting. It was concluded that hydrogels do not contribute to growth of seedlings in the nursery but they do so after transplanting. Hydrogels increase soil moisture in the soil, so they are recommended for use in semi-arid lands to boost the survival and growth of seedlings.

关键词： Hydrogels Moisture Growth Semi-Arid Lands

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The Impact of Model Based Offset Scaling Technique on the Amplitude Variation with Offset Responses from 3D Seismic Data Acquired from the Tano Basin, Offshore Ghana

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International Journal of Geosciences 2024年第1期15卷 40-53页

作者： Striggner Bedu-Addo sylvester Kojo Danuor Aboagye Menyeh Department of Physics Kwame Nkrumah University of Science and Technology Kumasi Ghana

Amplitudes have been found to be a function of incident angle and offset. Hence data required to test for amplitude variation with angle or offset needs to have its amplitudes for all offsets preserved and not stacked. Amplitude Variation with Offset (AVO)/Amplitude Variation with Angle (AVA) is necessary to account for information in the offset/angle parameter (mode converted S-wave and P-wave velocities). Since amplitudes are a function of the converted S- and P-waves, it is important to investigate the dependence of amplitudes on the elastic (P- and S-waves) parameters from the seismic data. By modelling these effects for different reservoir fluids via fluid substitution, various AVO geobody classes present along the well and in the entire seismic cube can be observed. AVO analysis was performed on one test well (Well_1) and 3D pre-stack angle gathers from the Tano Basin. The analysis involves creating a synthetic model to infer the effect of offset scaling techniques on amplitude responses in the Tano basin as compared to the effect of unscaled seismic data. The spectral balance process was performed to match the amplitude spectra of all angle stacks to that of the mid (26°) stack on the test lines. The process had an effect primarily on the far (34° - 40°) stacks. The frequency content of these stacks slightly increased to match that of the near and mid stacks. In offset scaling process, the root mean square (RMS) amplitude comparison between the synthetic and seismic suggests that the amplitude of the far traces should be reduced relative to the nears by up to 16%. However, the exact scaler values depend on the time window considered. This suggests that the amplitude scaling with offset delivered from seismic processing is only approximately correct and needs to be checked with well synthetics and adjusted accordingly prior to use for AVO studies. The AVO attribute volumes generated were better at resolving anomalies on spectrally balanced and offset scaled da

关键词： Amplitude Variation with Offset (AVO) Model Based Offset Scaling Technique Tano Basin

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Petrophysical Evaluation of Cape Three Points Reservoirs

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International Journal of Geosciences 2024年第2期15卷 162-179页

作者： Striggner Bedu-Addo sylvester Kojo Danuor Larry Pax Chegbeleh Department of Physics Kwame Nkrumah University of Science and Technology Kumasi Ghana Department of Earth Science University of Ghana Accra Ghana

The findings of a study to ascertain and assess the petrophysical characteristics of Cape Three Points reservoirs in the Western basin with a view to describe the reservoir quantitatively using Well Logs, Petrel and Techlog. The investigated characteristics, which were all deduced from geophysical wire-line logs, include lithology, porosity, permeability, fluid saturation, and net to gross thickness. To characterise the reservoir on the field, a suite of wire-line logs including gamma ray, resistivity, spontaneous potential, and density logs for three wells (WELL_1X, WELL_2X, and WELL_3X) from the Tano Cape Three Point basin were studied. The analyses that were done included lithology delineation, reservoir identification, and petrophysical parameter determination for the identified reservoirs. The tops and bases of the three wells analysed were marked at a depth of 1203.06 - 2015.64 m, 3863.03 - 4253.85 m and 2497.38 - 2560.32 m respectively. There were no hydrocarbons in the reservoirs from the studies. The petrophysical parameters computed for each reservoir provided porosities of 13%, 3% and 11% respectively. The water saturation also determined for these three wells (WELL_1X, WELL_2X and WELL_3X) were 94%, 95% and 89% respectively. These results together with the behaviour of the density and neutron logs suggested that these wells are wildcat wells.

关键词： Petrophysical Cape Three Points Reservoirs

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Navigating AI Cybersecurity: Evolving Landscape and Challenges

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Journal of Intelligent Learning Systems and Applications 2024年第3期16卷 155-174页

作者： Maryam Roshanaei Mahir R. Khan Natalie N. sylvester IST Department Pennsylvania State University Abington Abington USA

The rapid integration of artificial intelligence (AI) into critical sectors has revealed a complex landscape of cybersecurity challenges that are unique to these advanced technologies. AI systems, with their extensive data dependencies and algorithmic complexities, are susceptible to a broad spectrum of cyber threats that can undermine their functionality and compromise their integrity. This paper provides a detailed analysis of these threats, which include data poisoning, adversarial attacks, and systemic vulnerabilities that arise from the AI’s operational and infrastructural frameworks. This paper critically examines the effectiveness of existing defensive mechanisms, such as adversarial training and threat modeling, that aim to fortify AI systems against such vulnerabilities. In response to the limitations of current approaches, this paper explores a comprehensive framework for the design and implementation of robust AI systems. This framework emphasizes the development of dynamic, adaptive security measures that can evolve in response to new and emerging cyber threats, thereby enhancing the resilience of AI systems. Furthermore, the paper addresses the ethical dimensions of AI cybersecurity, highlighting the need for strategies that not only protect systems but also preserve user privacy and ensure fairness across all operations. In addition to current strategies and ethical concerns, this paper explores future directions in AI cybersecurity.

关键词： AI Cybersecurity Adversarial Attacks Defensive Strategies Ethical AI

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Enhancing Cybersecurity through AI and ML: Strategies, Challenges, and Future Directions

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Journal of Information Security 2024年第3期15卷 320-339页

作者： Maryam Roshanaei Mahir R. Khan Natalie N. sylvester Information Sciences and Technology Department Pennsylvania State University Abington USA

The landscape of cybersecurity is rapidly evolving due to the advancement and integration of Artificial Intelligence (AI) and Machine Learning (ML). This paper explores the crucial role of AI and ML in enhancing cybersecurity defenses against increasingly sophisticated cyber threats, while also highlighting the new vulnerabilities introduced by these technologies. Through a comprehensive analysis that includes historical trends, technological evaluations, and predictive modeling, the dual-edged nature of AI and ML in cybersecurity is examined. Significant challenges such as data privacy, continuous training of AI models, manipulation risks, and ethical concerns are addressed. The paper emphasizes a balanced approach that leverages technological innovation alongside rigorous ethical standards and robust cybersecurity practices. This approach facilitates collaboration among various stakeholders to develop guidelines that ensure responsible and effective use of AI in cybersecurity, aiming to enhance system integrity and privacy without compromising security.

关键词： Artificial Intelligence Machine Learning Cybersecurity Data Privacy and Security Ethical Standards

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Development of an active-site titrant for SARS-CoV-2 main protease as an indispensable tool for evaluating enzyme kinetics

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2349-2357页

作者： Rabea Voget Julian Breidenbach Tobias Claff Alexandra Hingst Katharina sylvester Christian Steinebach Lan Phuong Vu Renato H.Weiße Ulrike Bartz Norbert Sträter Christa E.Müller Michael Gütschow Pharmaceutical Institute Pharmaceutical&Medicinal ChemistryUniversity of BonnBonn 53121Germany Institute of Bioanalytical Chemistry Center for Biotechnology and BiomedicineLeipzig UniversityLeipzig 04103Germany Department of Natural Sciences University of Applied Sciences Bonn-Rhein-SiegRheinbach 53359Germany

A titrant for the SARS-CoV-2 main protease(M^(pro))was developed that enables,for the first time,the exact determination of the concentration of the enzymatically active M^(pro) by active-site *** covalent binding mode of the tetrapeptidic titrant was elucidated by the determination of the crystal structure of the enzyme–titrant *** fluorogenic substrates of M^(pro),including a prototypical,internally quenched Dabcyl-EDANS peptide,were compared in terms of solubility under typical assay *** exploiting the new titrant,key kinetic parameters for the M^(pro)-catalyzed cleavage of these substrates were determined.

关键词： COVID-19 SARS-CoV-2 Main protease Peptide nitriles Fluorogenic substrates Active-site titration X-ray crystallography Inner filter effect

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Performance of Continuous Wavelet Transform over Fourier Transform in Features Resolutions

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International Journal of Geosciences 2024年第2期15卷 87-105页

作者： Michael K. Appiah sylvester K. Danuor Alfred K. Bienibuor Department of Physics Kwame Nkrumah University of Science and Technology (KNUST) Kumasi Ghana Department of Chemical Sciences University of Energy and Natural Resources Sunyani Ghana

This study presents a comparative analysis of two image enhancement techniques, Continuous Wavelet Transform (CWT) and Fast Fourier Transform (FFT), in the context of improving the clarity of high-quality 3D seismic data obtained from the Tano Basin in West Africa, Ghana. The research focuses on a comparative analysis of image clarity in seismic attribute analysis to facilitate the identification of reservoir features within the subsurface structures. The findings of the study indicate that CWT has a significant advantage over FFT in terms of image quality and identifying subsurface structures. The results demonstrate the superior performance of CWT in providing a better representation, making it more effective for seismic attribute analysis. The study highlights the importance of choosing the appropriate image enhancement technique based on the specific application needs and the broader context of the study. While CWT provides high-quality images and superior performance in identifying subsurface structures, the selection between these methods should be made judiciously, taking into account the objectives of the study and the characteristics of the signals being analyzed. The research provides valuable insights into the decision-making process for selecting image enhancement techniques in seismic data analysis, helping researchers and practitioners make informed choices that cater to the unique requirements of their studies. Ultimately, this study contributes to the advancement of the field of subsurface imaging and geological feature identification.

关键词： Continuous Wavelet Transform (CWT) Fast Fourier Transform (FFT) Reservoir Characterization Tano Basin Seismic Data Spectral Decomposition

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Optimization and Validation of a Simple Spectrophotometric Based DPPH Method for Analysis of Antioxidant Activity in Aerated, Semi-Aerated and Non-Aerated Tea Products

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Open Journal of Applied Sciences 2024年第8期14卷 2207-2222页

作者： Simon Mwangi Kingori sylvester Cheruiyot Aron Cheruiyot Kirui Rugema Grace Uwamahoro Agnes Wangui Mwangi Kenya Agricultural and Livestock Research Organization-Tea Research Institute Kericho Kenya Department of Chemistry Egerton University Egerton Kenya Department of Food Science Dedan Kimathi University of Technology Nyeri Kenya Faculty of Food Science Hungarian University of Agriculture and Life Sciences Budapest Hungary

In this study, the simple DPPH UV-spectrophotometric analytical procedures were optimized and validated for the estimation of antioxidant properties in aerated, semi-aerated and non-aerated tea products as per the AOAC guidelines. The method was found to be simple, rapid, accurate and economical in estimating antioxidant properties in the different tea products. A (0.0100 ± 0.0001) g well ground tea sample was extracted directly in 80% v/v methanol in distilled water. The precision of the method had an RSD% of 1.695 with a linear relation equation of Y = 200.7X + 5.25 (r2 = 0.997). The method proved to be a reliable and effective tool in analysis of anti-oxidant properties in varied tea cultivars and their processed products.

关键词： UV-Spectrophotometric Optimized Validated Antioxidant

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Turbidite Dynamics and Hydrocarbon Reservoir Formation in the Tano Basin: A Coastal West African Perspective

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International Journal of Geosciences 2024年第2期15卷 137-161页

作者： Michael K. Appiah sylvester K. Danuor Striggner Bedu-Addo Alfred K. Bienibuor Department of Physics Kwame Nkrumah University of Science and Technology (KNUST) Kumasi Ghana Department of Chemical Sciences University of Energy and Natural Resources Sunyani Ghana

This study examines the turbidite dynamics and hydrocarbon reservoir formation in Ghana’s Tano Basin, which is located in coastal West Africa. Through an exploration of geological processes spanning millions of years, we uncover key factors shaping hydrocarbon accumulation, including source rock richness, temperature, pressure, and geological structures. The research offers valuable insights applicable to exploration, management, and sustainable resource exploitation in coastal West Africa. It facilitates the identification of exploration targets with higher hydrocarbon potential, enables the anticipation of reservoir potential within the Tano Basin, and assists in tailoring exploration and management strategies to specific geological conditions of the Tano Basin. Analysis of fluvial channels sheds light on their impact on landscape formation and hydrocarbon exploration. The investigation into turbidite systems unveils intricate interactions involving tectonics, sea-level fluctuations, and sedimentation patterns, influencing the development of reservoirs. An understanding of sediment transport and depositional settings is essential for efficient reservoir management. Geomorphological features, such as channels, submarine canyons, and distinct channel types, are essential in this situation. A detailed examination of turbidite channel structures, encompassing canyons, channel complexes, convex channels, and U-shaped channels, provides valuable insights and aids in identifying exploration targets like basal lag, channel levees, and lobes. These findings underscore the enduring significance of turbidite systems as conduits for sediment transport, contributing to enhanced reservoir management and efficient hydrocarbon production. The study also highlights how important it is to examine the configuration of sedimentary layers, stacking patterns, and angular laminated facies to identify turbidites, understand reservoir distribution, and improve well design. The dynamic nat

关键词： Reservoir Characterization Tano Basin Seismic Data Hydrocarbon Potential Channels Turbidites

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Diversity, abundance, and structure of tree communities in the Uluguru forests in the Morogoro region, Tanzania

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Journal of Forestry Research 2015年第3期26卷 557-569页

作者： David sylvester Kacholi Anthony Michael Whitbread Martin Worbes Crop Production Systems in the Tropics Georg-August University Goettingen Grisebachstr. 6 37077 GoettingenGermany Department of Biological Sciences Dar es Salaam University College of Education (DUCE)P. O. Box 2329 Dar es Salaam Tanzania International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Patancheru 502324 Andhra PradeshIndia

Uluguru forests are globally recognized as important biodiversity hotspots, but anthropogenic pressure threatens their value. This study examined species diver- sity, abundance, and structure of trees in the Uluguru for- ests. All trees of diameter at breast height （DBH）〉 10 cm were inventoried in seven forests ranging from 3 to 995 ha in area. A total of 900 stems, 101 species and 34 families were inventoried. Fabaceae was the most speciose family. Ehretia amoena Klotzsch was the most abundant species with relative abundance of 9.22 %. The forests differed significantly in species richness （26-93 species ha-l）, tree density （85-390 stems ha-l）, basal area （3-24 m2 ha-1） and Shannon-Wiener diversity （2.50--4.02）. Forest area was significantly and positively correlated with species richness （r = 0.92） and species diversity （r = 0.95）. Tree density showed significant positive correlation with speciesrichness （r = 0.80） and basal area （r = 0.85）. Milawilila and Nemele forests had highest floristic similarity （0.55） followed by Kimboza and Kilengwe （0.54） while the rest had similarity coefficients of less than 0.50. Despite leg- islative protection, many forests remain at risk and there- fore the possibility to conserve highly valuable tree species via enhanced protection or cultivation must be considered.

关键词： Eastern arc Biodiversity Disturbance Hotspots Similarity

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