375 research outputs found
High throughput synthesis of 2,5-substituted indoles using a titanium carbenoid bearing boronate functionality
A titanium benzylidene complex bearing a boronate group converted resin-bound esters into enol ethers. Suzuki cross-coupling with aryl iodides followed by cleavage with acid completed the solid-phase synthesis of 2,5-disubstituted N-Boc-indoles. Also reported is the use of tert-butyllithium and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane to convert an aryl bromide into an arylboronate in the presence of a dithiane, with simultaneous reduction of an aryl azide to an amine
Technology-enhanced learning in Asia: new educational possibilities for the tomorrow's doctors and tomorrow's cures
Ye
The Impact of Small Scale Mining on Irrigation Water Quality in Asante Akim Central Municipality of Ghana
Small scale mining is a major threat to water resources and agricultural activities in most mining communities across Ghana. This study investigated the effect of small scale mining on the quality of water for irrigation from some selected sites along a river and a reservoir which was used as a control. The physical and chemical parameters of the water samples were measured using standard methods for water quality analysis. The samples were acid digested and assayed using Atomic Absorption Spectrophotometry (AAS). The study revealed that several of the physico-chemical parameters (turbidity, pH, conductivity, TDS) and heavy metals such as Pb and Hg were significantly higher (5% level of significance) at the river sites compared to the reservoir. Whilst most of the parameters measured were within range of the Food and Agriculture Organisation (FAO) limit for irrigation water quality, Hg, Cd, K and turbidity levels were higher than FAO permissible limits for irrigation water. Hazard assessment based on the sodium adsorption ratio (SAR), US Salinity laboratory classification and the Wilcox diagram for irrigation water quality showed the water tobe within acceptable salinity and sodium limits for irrigation. It is inferred from the findings that activities of small scale miners along the river affects the quality of the water. The high turbidity and detection of some level of heavy metals in the water should be a major concern to stakeholders in the Municipality as continuous influx of small scale miners in the area could increase heavy metal concentration beyond the acceptable thresholds
Speed up Robust Features (SURF) with Principal Component Analysis-Support Vector Machine (PCA-SVM) for benign and malignant classifications
A novel Computer Aided Diagnosis (CADx) component is proposed for breast cancer classifications. Four major phases were conducted in this research. The first phase is pre-processing, this is followed by features extraction phase by using the Speed Up Robust Features (SURF). The next phase is features selection by using the Principal Component Analysis (PCA). The final phase is the classification phase to classify the cancer. Three different classifiers; Support Vector Machine (SVM), Linear Discriminant Analysis (LDA) and Decision Tree (DT) were compared in this research. Results obtained shows that the PCA-SVM performs the highest accuracy with 92.9% accurate compared to other classifiers.Keywords: breast cancer; CADx; SURF; PCA; SV
Compact UWB band-notched antenna with integrated bluetooth for personal wireless communication and UWB applications
A compact band-notched UWB (Ultra-Wide Band) antenna with integrated Bluetooth is developed for personal wireless communication and UWB applications. The antenna operates at the UWB frequency band (3.1-10.6 GHz) as well as Bluetooth (2.4-2.484 GHz), with band-notch characteristics at the Wireless Local Area Network (WLAN) frequency band (5-6 GHz). A new technique of integrating Bluetooth within a UWB band-notched antenna is developed and analyzed. The UWB frequency band is realized by utilizing a conventional cylindrical radiating patch and a modified partial ground plane. The Bluetooth band is integrated using a miniaturized resonator with the addition of capacitors. Further, to mitigate the interference of the WLAN frequency band within the UWB spectrum, a conventional slot resonator is integrated within the radiator to achieve the task. The antenna is designed and fabricated, and its response in each case is provided. Moreover, the antenna exhibits a good radiation pattern with a stable gain in the passband. The present antenna is also compared to state-of-the-art structures proposed in the literature. The miniaturized dimensions (30 x 31 mm 2 ) of the antenna make it an excellent candidate for UWB and personal wireless communication applications.The publication of this article was funded by the Qatar National Library. Mirjavadi also appreciates the help from the Fidar Project Qaem Company (FPQ)
Testing The Equality Of Location Parameters For Skewed Distribution Using S1 With High Breakdown Robust Scale Estimators.
A simulation study had been carried out to compare the Type I error and power of S1 , a statistic recommended by Babu et al {1999) for testing the equality of location parameters for skewed distributions
Comparing the “Typical Score” Across Independent Groups Based on Different Criteria for Trimming
Nonnormality and variance heterogeneity affect the validity of the traditional tests for treatment group equality (e.g. ANOVA F-test and t-test), particularly when group sizes are unequal. Adopting trimmed means instead of the usual least
squares estimator has been shown to be mostly affective in combating the deleterious effects of nonnormality
Bacteriology of orofacial infection
Objective: To establish the causative organisms of orofacial infections and their antimicrobial susceptibilities. Patients and Methods: In this retrospective chart review, 416 samples of pus were obtained from 409 patients with orofacial infection attending a dental school between 1994 and 1998 were sent for culture and susceptibility testing. Results: 109 samples grew normal oral flora and 228 samples grew pathogens. No organisms were isolated in 79 samples. The most common pathogens isolated were viridans streptococci (22.4), Staphylococcus aureus (18.4), enteric gram-negative bacteria (20.2), and Pseudomonas aeruginosa (9.7). All strains of viridans streptococci were susceptible to penicillin. Viridans streptococci and Staphylococcus aureus showed good susceptibilities to erythromycin of 85.7 and 87.1, respectively. Of the enteric gram-negative bacteria, 47.8 were resistant to ampicillin. No anaerobic organisms were isolated in this study. Conclusions: The profile of aerobic isolates and their susceptibilities to antimicrobial agents should assist in selecting empirical therapy and directing therapy for orofacial infection. Inclusion of antimicrobial agents against anaerobic bacteria is recommended
Integrated assessment and decision-support tool for community-based vulnerability and adaptation to storm surges in four coastal areas in Bangladesh
Bangladesh has been identified as one of the countries most vulnerable to climate
change and rising sea-level. This is because it is located at the northern end of the
funnel-shaped Bay of Bengal, and as a consequence it has experienced a number of
severe storm surges in the last three decades. The inhabitants of the coastal region
are very poor, and the surges have pushed them to a ‘tipping-point’; that is, the point
of desperation which is exacerbating the socio-economic threats to their existence.
The study reported here aimed to explore the perceptions of coastal communities
with regard to vulnerability and adaptation (V & A) strategies in four different areas of
Bangladesh in order to reduce their vulnerability to future storm surges. After
reviewing the impact assessment guidelines of the Intergovernmental Panel on
Climate Change (IPCC), United States Country Studies Program (USCSP) and
United Nations Environment Programme (UNEP), the researchers applied the
Participatory Rapid Appraisal (PRA) method (a behavioural environmental decisionmaking tool) to survey 160 participants in four case-study areas,with 20 participants in two sessions in each case. The evaluation of V & A was implemented and prioritised in this study by a measuring scale, called the ‘weighted matrix index’. This study not only considered the integrated assessment of V & A but it also classified the levels of vulnerability and adaptation in different categories. Additionally, it provides a comparative picture of the vulnerabilities for similar risks in different types of communities. The study emphasizes some key aspects: a. the composite nature of various levels of V & A issues; b. the constraints to adaptation implementation; c. how to overcome those constraints. These key aspects demonstrate and stress that adaptation policy needs to be implemented immediately in Bangladesh in order to reduce and manage future vulnerability in the coastal region of Bangladesh under the potential climate change regimes.Md Aboul Fazal Younus, Sabrina Shahrin Sharna, Tamanna Binte Rahma
Investigation of Potential Grounding Compound for Portable Applications
This paper applies to the electrical engineering world by making earthing system portable in providing low and acceptable resistance path. The system is develop in a small scale portable earthing system against the massiveness of Earth and becomes leverage if soil at the place is not suitable for plant grounding system. Hence, this paper presents findings on the research of new grounding medium material that will be housed in a small scale enclosure which behaves like native earth related earthing system by using kaolin and bauxite. The data obtained from lightning flashover testing, morphological and chemical composition of material analysis indicated that bauxite is more useful for portable grounding system application much better than kaolin in term of zero reference point function. The portable earthing system can be apply to air aviation systems , railway systems and military sectors particularly for electronic equipment zero referencing
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