Optimal Water Allocation from Subsurface Dams: A Risk-Based Optimization Approach

Subsurface dams, strongly advocated in the 1992 United Nations Agenda-21, have been widely studied to increase groundwater storage capacity. However, an optimal allocation of augmented water with the construction of the subsurface dams to compensate for the water shortage during dry periods has not so far been investigated. This study, therefore, presents a risk-based simulation–optimization framework to determine optimal water allocation with subsurface dams, which minimizes the risk of water shortage in different climatic conditions. The developed framework was evaluated in Al-Aswad falaj, an ancient water supply system in which a gently sloping underground channel was dug to convey water from an aquifer via the gravity force to the surface for irrigation of downstream agricultural zones. The groundwater dynamics were modeled using MODFLOW UnStructured-Grid. The data of boreholes were used to generate a three-dimensional stratigraphic model, which was used to define materials and elevations of five-layer grid cells. The validated groundwater model was employed to assess the effects of the subsurface dam on the discharge of the falaj. A Conditional Value-at-Risk optimization model was also developed to minimize the risk of water shortage for the augmented discharge on downstream agricultural zones. Results show that discharge of the falaj is significantly augmented with a long-term average increase of 46.51%. Moreover, it was found that the developed framework decreases the water shortage percentage in 5% of the worst cases from 87%, 75%, and 32% to 53%, 32%, and 0% under the current and augmented discharge in dry, normal, and wet periods, respectively

Revisiting the Prevalence of Autism Spectrum Disorder among Omani Children: A multicentre study

Objectives: This study aimed to provide an updated estimate of the prevalence of autism spectrum disorder (ASD) among Omani children. Methods: This retrospective descriptive study was conducted from December 2011 to December 2018. Data were retrieved from the three main autism diagnostic centres in Oman: Sultan Qaboos University Hospital, Royal Hospital and Al-Massarah Hospital. The ASD diagnosis was made by experienced clinicians based on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The overall population prevalence estimates per 10,000 children aged 0–14 years old in Oman were calculated using the denominator of the mid-period population data. Results: A total of 1,705 ASD cases were identified with the majority of cases being male (78.1%). The overall prevalence rate of ASD was estimated at 20.35 per 10,000 children (95% confidence interval: 19.39–21.32) between 2012–2018. Boys were found to have a 3.4-fold higher prevalence of ASD than girls (31.23/10,000 versus 9.07/10,000). Regionally, the majority of cases were found in the capital, Muscat, where the highest prevalence was 36.51 cases per 10,000 children. Conclusion: The prevalence of ASD among Omani children is 15-fold higher than estimates from 2011. This increase can be attributed to improvements in diagnostic services, increased awareness of ASD, better screening programmes and changes in diagnostic criteria. In addition, this increase in prevalence suggests a need for a registry of developmental disabilities and more extensive diagnostic and rehabilitation services in Oman.Keywords: Autism Spectrum Disorder; Epidemiology; Prevalence; Oman

Indications of Validity and Reliability of TIMSS Standards List with the Fourth Grade Cambridge Mathematics Curriculum from Mathematics Teachers and Supervisors Point of View in the Sultanate of Oman

هدفت الدراسة لتوفير قائمة موثوقة تتمتع بدلالات صدق وثبات مرتفعة، لموائمة معايير الدراسة الدولية للعلوم والرياضيات TIMSS مع منهاج الرياضيات كامبريدج للصف الرابع في سلطنة عمان، وتكوّنت القائمة من 39 معيارا، توزعت على خمسة محاور(الأعداد الكاملة، العبارات الجبرية، القياس، الكسور والأعداد الكسرية، الهندسة). طبقت القائمة على عينة تكونت من 616 (584 معلمًا، 32 مشرفًا). توصّلت الدراسة إلى أن المعايير كانت فعّالة لقياس محاور القائمة، وكذلك توصّلت إلى عدة دلالات للصدق تمثلت في الصدق الظاهري وصدق البناء، وتوصلت أيضًا إلى دلالات مناسبة ومرتفعة لثبات القائمة. وأوصت الدراسة باستخدام القائمة لمراجعة منهاج الرياضيات كامبريدج للصف الرابع في سلطنة عمان للحكم على مواءمته لمعايير الدراسة الدولية للعلوم والرياضيات TIMSS

The relationships between body and otolith size of the blueline snapper Lutjanus coeruleolineatus (Rüppell, 1838) collected from the coasts of Oman, Arabian Sea

Relationships between fish length and otolith length and width were examined in the blueline snapper Lutjanus coeruleolineatus (Lutjanidae) collected from the coasts of Oman, Arabian Sea. The values of exponent b from the relationships between fish total length and otolith length and total length and otolith width were estimated representing the close fitness of otolith size with fish size. Both relationships were statistically significant, which means both otolith length and width can be used to retrieve the fish original size. The analysis of covariance (ANCOVA) was used to test the effect of the categorical factor of species in the fish length and otolith length relationship. This study represents the first reference available on the relationship of fish size and otolith size for L. coeruleolineatus in the Arabian Sea area. Results from this study will offer original data on quantitative biometric relationships between body and otolith measurements of fish species in Arabian Sea region. By obtaining the mathematical model showing the relationship of the otolith size and fish length will enable fisheries biologists to know the size of the fish that has been eaten an information which important for fish biologists

Power sector of Oman--Today and tomorrow

In December 1999 the council of Ministers of Sultanate of Oman approved policies for the wholesale restructuring and privatization of the sultanate's electricity and related water sectors. The government started carrying out unbundling of the sector and setting up independent companies on a commercial basis. The companies are now shaping up for future electricity market. Beside these evolving structural changes, there would be a need to change their generation mix. Oman relies 100% on fossil fuel resources (mainly gas) for its power generation. However, Oman's natural gas supplies are largely committed and the country may become a net natural gas importer in the near future. Today, there is a great incentive for Oman to exploit renewable energy in order to face the changing environment and to guard against future trends. The electricity companies should investigate the renewable potential and work with Omani government and Authority for Electricity Regulation (AER) to establish policy support for large-scale renewable energy plants. Beside there is a huge potential for demand-side management and energy conservation which should be exploited for the benefit of the country and of the environment.Oman Electricity companies Renewable energy Demand-side management

Technoeconomical Assessment of Optimum Design for Photovoltaic Water Pumping System for Rural Area in Oman

Photovoltaic (PV) systems have been used globally for a long time to supply electricity for water pumping system for irrigation. System cost drops down with time since PV technology, efficiency, and design methodology have been improved and cost of wattage drops dramatically in the last decade. In the present paper optimum PV system design for water pumping system has been proposed for Oman. Intuitive and numerical methods were used to design the system. HOMER software as a numerical method was used to design the system to come up with optimum design for Oman. Also, REPS.OM software has been used to find the optimum design based on hourly meteorological data. The daily solar energy in Sohar was found to be 6.182 kWh/m2·day. However, it is found that the system annual yield factor is 2024.66 kWh/kWp. Furthermore, the capacity factor was found to be 23.05%, which is promising. The cost of energy and system capital cost has been compared with that of diesel generator and systems in literature. The comparison shows that the cost of energy is 0.180, 0.309, and 0.790 USD/kWh for PV-REPS.OM, PV-HOMER, and diesel systems, respectively, which sound that PV water pumping systems are promising in Oman

Modern Recharge in a Transboundary Groundwater Basin Deduced from Hydrochemical and Isotopic Investigations: Al Buraimi, Oman

Groundwater samples (54) collected from different geological units (alluvium, Tertiary, ophiolite, and Hawasina) located in the transboundary groundwater basin in north Oman at the United Arab Emirates (UAE) borders were analyzed for general hydrochemistry and water isotopes, and subsets thereof were analyzed for 14C and 3H and 87Sr/86Sr. The chemical composition, percentage of modern carbon (pmc), δ2H, δ18O, and 87Sr/86Sr of the groundwater in the study area progressively change from the recharge zone in the elevated area of the North Oman Mountains (NOM) to the flat plains at the UAE borders. While the water-rock interaction is the dominant process controlling the groundwater chemistry, evaporation and groundwater mixing affect the hydrochemistry at the UAE borders. Therefore, groundwater evolves from carbonate-dominant in the NOM into sodium chloride-dominant close to the UAE borders. It is also evident that groundwater lateral recharge from the ophiolites into the alluvium retains the chemical affinity of the ophiolites. Groundwater dating (high pmc), homogeneous 87Sr/86Sr ratios, and enriched δ2H and δ18O demonstrate the presence of modern recharge in the shallow zones of the ophiolites and alluvium. However, deep zones and areas at the UAE border contain older groundwater form during cooler and wetter climatic conditions as supported by the depleted δ2H and δ18O and lower 87Sr/86Sr ratios and pmc. Furthermore, the data clearly showed that modern groundwater mixes with older groundwater along the flow path from the NOM into the UAE border. Modern recharge occurs as lateral recharge from NOM and direct recharge in the plain area. The current findings support future development of aflaj system along NOM slopes and shallow wells in the plain areas

Alkene protection against acid using a bromide substituent: application in a total synthesis of (−)-6,7-dideoxysqualestatin H5

The presence of a bromide substituent, instead of a hydrogen or methyl group, on a carbon–carbon double bond, protects the alkene from addition reactions when exposed to trifluoroacetic acid. This concept is used to circumvent concomitant loss of unsaturation in a late-stage acid-catalysed 6,8- to 2,8-dioxabicyclo[3.2.1]octane rearrangement towards (−)-6,7-dideoxysqualestatin H5. The inertness of the alkenyl bromide functionality is demonstrated through several synthetic transformations in the assembly of the rearrangement substrate. Completion of the natural product synthesis is facilitated by post-rearrangement removal of the bromide substituent through stereoselective C–C cross-coupling in the presence of ester and hydroxyl functionalities

Alkene protection against acid using a bromide substituent: application in a total synthesis of (−)-6,7-dideoxysqualestatin H5

The presence of a bromide substituent, instead of a hydrogen or methyl group, on a carbon–carbon double bond, protects the alkene from addition reactions when exposed to trifluoroacetic acid. This concept is used to circumvent concomitant loss of unsaturation in a late-stage acid-catalysed 6,8- to 2,8-dioxabicyclo[3.2.1]octane rearrangement towards (−)-6,7-dideoxysqualestatin H5. The inertness of the alkenyl bromide functionality is demonstrated through several synthetic transformations in the assembly of the rearrangement substrate. Completion of the natural product synthesis is facilitated by post-rearrangement removal of the bromide substituent through stereoselective C–C cross-coupling in the presence of ester and hydroxyl functionalities