359 research outputs found
Efficacy of mefenoxam is affected by a lag period between application and inactivation of Pythium species
A study was undertaken to investigate whether inactivation of Pythium by mefenoxam takes place as soon as it comes in contact with the fungicide. Laboratory experiments were conducted which involved three sensitive isolates of P. aphanidermatum (EC50<1 ”g mL-1), three sensitive isolates of P. spinosum (EC50<1 ”g mL-1) and two resistant isolates of P. aphanidermatum (EC50>100 ”g mL-1). In liquid cultures, inactivation of the sensitive Pythium isolates by mefenoxam took place between 12 hr and >96hr at concentrations from 1 to 100 ”g mL-1. The time required for inactivation was negatively correlated with the concentration of mefenoxam (P<0.05). Colonization of cucumber seeds placed at different distances from the sensitive Pythium inoculum in soil amended with 1 and 5 ”g mL-1 mefenoxam occurred in the first 12 hr. However, colonization was reduced after 24 hr and was completely inhibited after 96 hr. Efficiency of colonization in the sensitive Pythium populations was found to have a negative correlation with the concentration of mefenoxam used. Growth and colonization by the resistant Pythium isolates were not found to be affected with mefenoxam. This study appears to be the first report of presence of a lag period between application of mefenoxam and time taken to inactivate Pythium
Choice of GCC Construction Market Entry Mode
The international construction sector is one essential organ of the global economic body. More construction companies target international construction markets and would need to make a decision as the most appropriate mode to enter a particular market. This purpose of the study is to develop a framework to guide the decision making process for contractors considering entry to Gulf Cooperation Council (GCC) construction markets. This market emphasis the delivery of innovation and creating smart facilities and infrastructure. The study analyzed data from 86 international contractors who are listed as the most successful international contractors in the GCC countries. The paper examined the key factors that have influenced contractorsâ entry strategy. The paper presents the results from the analysis of the proposed selection framework through interviews with a sample of top management executives in contracting firms. The study found that firmsâ initial choice of a specific entry mode is a key strategic decision made to ensure successful investment. Firms believed that the option of entry mode adjustment is hard without incurring significant losses of time and money. Further, it was found that construction unique characteristics imply different priorities than those in other industries to enter foreign markets. Furthermore, The study concluded that most of GCC markets require the entry using permanent modes (branches or sole venture companies), eventually a set of recommendations were introduced to facilitate the entry process and ensure successful entry to GCC construction markets
Biotic and Abiotic Stresses of Major Fruit Crops in Oman: A Review
Oman is located in an arid region of the world that is characterized by adverse climatic conditions, including heat and drought. In recent years, it has also been affected by climate turbulence and the occurrence of severe weather, such as cyclones and heat/cold waves affecting large agricultural areas of the country. Fruit cultivation area represents 31% of the total cultivated area (97,239.58 ha) in the country. However, the production share is only 17% of the total crop production in the country (2.6 million tons). About 90% of the fruit cultivation area is dominated by date palm, banana, lime, and mango. In addition to the abiotic stresses, such as drought, heat, and salinity, major fruit crops have declined in recent years due to various biotic stressors, primarily insect pests, and diseases. For several decades, the date palm has suffered from the Dubas bug and in recent years from Red Palm Weevil. Lime has been infected with Witchâs Broom Disease of Lime (WBDL) caused by âCandidatus Phytoplasma aurantifoliaâ that has led to the decline of production to 25% from its peak in the nineties. Banana is Oman`s second-largest fruit crop in production and export. It has also been the subject of studies due to losses incurred by farmers during pre-and post-harvest stages, in addition to several pests and diseases that affect bananas in Oman. Mango is another major fruit crop that is primarily cultivated in northern Oman. Severe infection with mango decline has led to the eradication of mango orchards from many regions of Oman, particularly in Batinah Coast, where increased salinity has led to a decline in mango yield. Research conducted in Oman has investigated several aspects of these challenges. This review paper summarizes the outcome from studies conducted in the country and proposes directions towards resolving current and future challenges to the fruit industry
Complete Chloroplast Genome Sequence of Omani Lime (Citrus aurantiifolia) and Comparative Analysis within the Rosids
The genus Citrus contains many economically important fruits that are grown worldwide for their high nutritional and medicinal value. Due to frequent hybridizations among species and cultivars, the exact number of natural species and the taxonomic relationships within this genus are unclear. To compare the differences between the Citrus chloroplast genomes and to develop useful genetic markers, we used a reference-assisted approach to assemble the complete chloroplast genome of Omani lime (C. aurantiifolia). The complete C. aurantiifolia chloroplast genome is 159,893 bp in length; the organization and gene content are similar to most of the rosids lineages characterized to date. Through comparison with the sweet orange (C. sinensis) chloroplast genome, we identified three intergenic regions and 94 simple sequence repeats (SSRs) that are potentially informative markers with resolution for interspecific relationships. These markers can be utilized to better understand the origin of cultivated Citrus. A comparison among 72 species belonging to 10 families of representative rosids lineages also provides new insights into their chloroplast genome evolution
A Structured Approach to Insider Threat Monitoring for Offensive Security Teams
In many countries, government agencies resort to third parties to acquire security services of many kinds, including Red Team operations to test the effectiveness of own defenses mechanisms. Absolute trust is a key requirement, lest a potentially devastating finding be exploited by a treacherous Red Team against the same entity which commissioned the operation, or sold to its adversaries. In our endeavour as a joint private-academic initiative to address this peculiar market, we observed that a structured approach to this issue is much less common than we would have expected. In this work, we outline the process we are devising to offer customers a verified environment, but integrating it with an evidence-based proof of their correct behavior during the operation, striving to solve the âQuis custodiet ipsos custodesâ struggle in an offensive setting
Towards the Creation of Interdisciplinary Consumer-Oriented Security Metrics
Information systems are evolving: IoT devices and Cyber-physical systems (CPS) impact on the security of assets and people in the real world. Old cybersecurity approaches, which focused on seeing humans 'as a problem', could be substitute by new paradigms of seeing humans 'as a solution'. Therefore, consumers awareness will be one of the building blocks, as well as initiative that aim to create a set of standardized security metrics that can evaluate the security of systems. In order to do that, researchers need to study which are the essential factors that our future metrics should focus on. In this paper we analyzed this problem over CPS while assuming the consumer perspective. We summarize the state of the art in security metrics and advocate the need for a research effort aimed at taking the field to a new level of formal soundness and practical usability by considering interdisciplinary implications on cybersecurity
Impact of quantum confinement on transport and the electrostatic driven performance of silicon nanowire transistors at the scaling limit
In this work we investigate the impact of quantum mechanical effects on the device performance of n-type silicon nanowire transistors (NWT) for possible future CMOS applications at the scaling limit. For the purpose of this paper, we created Si NWTs with two channel crystallographic orientations <110> and <100> and six different cross-section profiles. In the first part, we study the impact of quantum corrections on the gate capacitance and mobile charge in the channel. The mobile charge to gate capacitance ratio, which is an indicator of the intrinsic performance of the NWTs, is also investigated. The influence of the rotating of the NWTs cross-sectional geometry by 90o on charge distribution in the channel is also studied. We compare the correlation between the charge profile in the channel and cross-sectional dimension for circular transistor with four different cross-sections diameters: 5nm, 6nm, 7nm and 8nm. In the second part of this paper, we expand the computational study by including different gate lengths for some of the Si NWTs. As a result, we establish a correlation between the mobile charge distribution in the channel and the gate capacitance, drain-induced barrier lowering (DIBL) and the subthreshold slope (SS). All calculations are based on a quantum mechanical description of the mobile charge distribution in the channel. This description is based on the solution of the Schrödinger equation in NWT cross sections along the current path, which is mandatory for nanowires with such ultra-scale dimensions
Probabilistic seismic hazard maps for the sultanate of Oman
This study presents the results of the first probabilistic seismic hazard assessment (PSHA) in the framework of logic tree for Oman. The earthquake catalogue was homogenized, declustered, and used to define seismotectonic source model that characterizes the seismicity of Oman. Two seismic source models were used in the current study; the first consists of 26 seismic source zones, while the second is expressing the alternative view that seismicity is uniform along the entire Makran and Zagros zones. The recurrence parameters for all the seismogenic zones were determined using the doubly bounded exponential distribution except the zones of Makran, which were modelled using the characteristic distribution. Maximum earthquakes were determined and the horizontal ground accelerations in terms of geometric mean were calculated using ground-motion prediction relationships developed based upon seismic data obtained from active tectonic environments similar to those surrounding Oman. The alternative seismotectonic source models, maximum magnitude, and ground-motion prediction relationships were weighted and used to account for the epistemic uncertainty. Hazard maps at rock sites were produced for 5 % damped spectral acceleration (SA) values at 0.1, 0.2, 0.3, 1.0 and 2.0 s spectral periods as well as peak ground acceleration (PGA) for return periods of 475 and 2,475 years. The highest hazard is found in Khasab City with maximum SA at 0.2 s spectral period reaching 243 and 397 cm/s[superscript 2] for return periods 475 and 2,475 years, respectively. The sensitivity analysis reveals that the choice of seismic source model and the ground-motion prediction equation influences the results most.Oman Ministerial Cabinet (project number 22409017
Poster: Continual Network Learning
We make a case for in-network Continual Learning as a solution for seamless adaptation to evolving network conditions without forgetting past experiences. We propose implementing Active Learning-based selective data filtering in the data plane, allowing for data-efficient continual updates. We explore relevant challenges and propose future research directions
Passive Seismic Tomography Using Induced Seismicity at a Petroleum Field in Oman
A borehole network consisting of 5 monitoring wells was used to monitor the induced
seismicity at a producing petroleum field for a period of about 11 months. Nearly 5400
microseismic events were analyzed and utilized in imaging the reservoir based on a new doubledifference
(DD) seismic tomography. The DD tomography method simultaneously solves for
event locations and Vp, Vs, and Vp/Vs models using absolute and differential P, S and S-P
arrival times. Microseismicity in the field was primarily caused by compaction of the reservoir in
and above the gas bearing formation and was distributed along the two major northeastsouthwest
(NE-SW) faults in the field. The model resolution analysis based on the checkerboard
test and the resolution matrix showed that the central part of the model was relatively well
resolved for the depth range of 0.7 to 1.1 km. Clear velocity contrasts were imaged across most
parts of the two NE-SW faults. Vp/Vs ratio estimations from the tomographic inversion were
low (<1.75) in the shallow depth range, likely due to lithology and gas content, whereas they
were large (>1.75) in the deeper part of the model, likely due to fluid saturated formation. In this
study seismic tomography showed a great potential for reservoir imaging and property estimation
using induced seismicity.Petroleum Development Oma
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