17,509 research outputs found

    Assessment of Students Performances in Biology: Implication for Measurements and Evaluation of Learning

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    Scienceeducation is believed to be a vital tool for individual and societal development at large. The persistent low levels of students' achievement in sciences at the various public examinations in Nigeria have continued to draw the attention of major stakeholders in education. This study examined academic achievement of Senior Secondary School students in biology and gender difference in students' achievement was examined. Ex-post facto design of descriptive research was adopted for the study. A proforma was used to collect data from a sample of two hundred (200) students, selected using stratified random sampling procedure from the Science secondary schools in Kano state Nigeria. The data collected were the students' performances in biology achievement tests. The data were analysed using descriptive statistics and independent-sample t-test. Overall results showed that the test internal consistency reliability is low and unsatisfactory; the students performed below average (M=47.02, SD=16.493 (47%). Similarly, gender difference exists in biology performance with another significant difference between performance of urban and rural school students. The study concludes that, biology test used in Kano state qualifying examinations to assess students potential ability in biology is not a reliable measurement tool and that, academic performance of students in biology is unsatisfactory and evidence of differential performance between gender and schools locations. The implication for measurements and evaluation of learning as well as recommendations has been discussed

    Uses of acetoacetanilide for the synthesis of thiophene derivatives with cytotoxic activities

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    The reaction of acetoacetanilide 1 with elemental sulfur and malononitrile 2 gave the thiophene derivative 3. The latter was the key starting material for the synthesis of different thiophene and fused derivatives through its reaction with aryldiazonium chloride, benzaldehyde and acetic anhydride. Moreover, the reaction with phenylisothiocyanate produced fused derivative. The reaction of compound 3 with elemental sulfur produced dithiophene derivative. In addition, the reaction of compound 3 with ethylcyanoacetate produced N-cyanoacetamide derivative that was capable for further heterocyclizations through its reaction with different reagents. The cytotoxicity of the newly synthesized products was evaluated against the three cancer cell lines namely MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), and SF-268 (CNS cancer) where some compounds showed optimal cytotoxicity. The results showed that compounds 5a, 5b, 8, 22, and 23 exhibited optimal cytotoxic effect against cancer cell lines.               KEY WORDS: Thiophene, Thieno[2,3-d]pyrimidine, Coumarin, Cytotoxicity Bull. Chem. Soc. Ethiop. 2017, 31(3), 519-534.   DOI: http://dx.doi.org/10.4314/bcse.v31i3.1

    Future Community-Based Ecotourism (CBET) development

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    Ecotourism is an alternative form of tourism and is usually confused with natural and cultural tourism.CBET is fast becoming a popular biodiversity conservation tool that develops and benefits the local community. Based on the context of conservation theory and practice, Community-Based Ecotourism (CBET) is a form of community-based natural resource management. However, a sustainable CBET development through Community Capacity Building (CCB)programs is not something that it easily achievable. Local community’s capacity varies from one culture to another. It takes a high level of community participation, in order for it to come to a level where the community members themselves are motivated to participate and contribute to the development of the program. This fully qualitative research involved 15 respondents from the community of Kg. Selai, Bekok in Johor, Malaysia. The result show there are five factors that sustained the ecotourism development based for Orang Asli Community in Kg. Selai, namely, existing CBET development, past CBET development, local community participation in planning stage of tourism, local participation in implementation stage of tourism and participation in nature conservation

    Weak Isospin Violations in Charged and Neutral Higgs Couplings from SUSY Loop Corrections

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    Supersymmetric QCD and supersymmetric electroweak loop corrections to the violations of weak isospin to Yukawa couplings are investigated. Specifically it involves an analysis of the supersymmetric loop corrections to the Higgs couplings to the third generation quarks and leptons. Here we analyze the SUSY loop corrections to the charged Higgs couplings which are then compared with the supersymmetric loop corrections to the neutral Higgs couplings previously computed. It is found that the weak isospin violations can be quite significant, i.e, as much as 40-50% or more of the total loop correction to the Yukawa coupling. The effects of CP phases are also studied and it is found that these effects can either enhance or suppress the weak isospin violations. We also investigate the weak isospin violation effects on the branching ratio BR(H−→tˉb)/BR(H−→νˉττ−)BR(H^-\to\bar t b)/ BR(H^-\to \bar\nu_{\tau}\tau^-) and show that the effects are sensitive to CP phases. Thus an accurate measurement of this branching ratio along with the branching ratio of the neutral Higgs boson decays can provide a measure of weak isospin violation along with providing a clue to the presence of supersymmetry.Comment: 20 pages, 9 figure

    Examining the cancellation mechanism of neutron EDM in a model with dilaton-dominated susy breaking

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    We examine the cancellation mechanism between the different contributions to the electric dipole moment of the neutron in a model with dilaton-dominated SUSY breaking. We find these accidental cancellations occur at few points in parameter space. For a wide region of this space we must constrain the phase of μ\mu to be of order 10−110^{-1} and have the phases of AA and μ\mu strongly correlated in order to have small neutron EDM. Moreover, we consider the indirect CP violation parameter ϵ\epsilon in this region where the electric dipole moment is less than the experimental limit and find that we can generate ϵ\epsilon of order 10−610^{-6}

    A General Framework to Compare Announcement Accuracy: Static vs LES-based Announcement

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    Service providers often share delay information, in the form of delay announcements, with their customers. In practice, simple delay announcements, such as average waiting times or a weighted average of previously delayed customers, are often used. Our goal in this paper is to gain insight into when such announcements perform well. Specifically, we compare the accuracies of two announcements: (i) a static announcement that does not exploit real-time information about the state of the system and (ii) a dynamic announcement, specifically the last-to-enter-service (LES) announcement, which equals the delay of the last customer to have entered service at the time of the announcement. We propose a novel correlation-based approach that is theoretically appealing because it allows for a comparison of the accuracies of announcements across different queueing models, including multiclass models with a priority service discipline. It is also practically useful because estimating correlations is much easier than fitting an entire queueing model. Using a combination of queueing-theoretic analysis, real-life data analysis, and simulation, we analyze the performance of static and dynamic announcements and derive an appropriate weighted average of the two which we demonstrate has a superior performance using both simulation and data from a call center.

    Hubungan Explosive Power Otot Lengan Bahu dengan Kemampuan Shooting Under Ring pada Tim Bolabasket Putra Sman 6 Peknbaru

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    ABSTRACK : This Researchis a correlation study. This research was conducted at the SMAN 6 Pekanbaru men basketball team. Data were obtained and collected by the independent variable tests (explosive power arm shoulder muscles) and test the dependent variable (shooting under ring capability). The data obtained were analyzed using product moment correlation analysis.Explosive relationship Sleeve Shoulder Muscle Power Shooting Capability under Ring with the SMAN 6 Men's Basketball Team Pekanbaru. Problem identification results showed that men's basketball player SMAN 6 Pekanbaru yet under the ring shooting ability not Maximum. It initials due to the lack of the factors associated with the development of these techniques. By therefore then with lifted Research carried problem "Does the Relations explosive power arm shoulder muscles with shooting capability under the ring at SMAN 6 men's basketball team Pekanbaru?" The proposed research hypotheses on Research husband is "There are Relationship explosive power arm shoulder muscles with shooting capabilities under men's rings on basketball team SMAN 6 Pekanbaru." This study aims to determine the relationship label explosive power arm shoulder muscles with shooting capability under the ring on men's basketball team SMAN 6 Pekanbaru.Results of the analysis showed that there is a relationship explosive power arm shoulder muscles with shooting under ring capabilities at the SMAN 6 Pekanbaru men basketball team. Based on product moment correlation analysis produced a correlation coefficient (r) of 0.5686, which means there is a correlation between the independent variable and dependent variables and the t test result of tcount 2.4883 and ttable 1,771. Means tcount > ttable so it can be concluded that H0 is rejected and Ha is accepted and shows that a significant relationship between the two variables

    Kesan penggunaan koswer multimedia animasi visual terhadap pencapaian pelajar dalam mata pelajaran matematik

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    Ramai pelajar yang bermasalah dalam topik Pelan dan Dongakan. Ini kerana pelajar sukar untuk membayangkan objek yang tersembunyi melalui proses pengajaran dan pembelajaran (P&P) secara konvensional. Penyelidik telah membangunkan satu koswer multimedia animasi visual dalam topik Pelan dan Dongakan dengan menerapkan kesemua elemen-elemen yang dapat membantu meningkatkan kemahiran visual iaitu elemen animasi, video, audio, grafik dan teks. Seterusnya, kajian kuasi eksperimental ini turut dijalankan bertujuan untuk mengetahui kesan penggunaan koswer multimedia animasi visual terhadap pencapaian pelajar bagi mata pelajaran Matematik di sekolah menengah. Ujian Pra dan Ujian Pos digunakan untuk melihat perbezaan pencapaian yang signifikan selepas menggunakan koswer multimedia animasi visual yang menggunakan teori Kognitif Visual Wiley. Responden yang terlibat dalam kajian ini ialah seramai 40 orang pelajar Tingkatan Lima yang dibahagikan kepada dua kumpulan iaitu kumpulan rawatan dan kumpulan kawalan yang dipilih daripada sebuah sekolah di daerah Batu Pahat, Johor. Hasil analisis menunjukkan peningkatan skor min markah bagi pelajar kumpulan rawatan. Hasil analisis ujian-t (paired-sample-t-test) membuktikan bahawa wujudnya perbezaan skor min markah yang signifikan di antara markah ujian pra dan markah ujian pos bagi kumpulan rawatan. Oleh itu, terdapat perbezaan yang signifikan di antara skor min markah ujian pra dan ujian pos bagi pelajar kumpulan rawatan selepas menggunakan koswer multimedia animasi visual. Manakala instrumen soal selidik yang digunakan untuk melihat tahap penerimaan pelajar selepas menggunakan koswer multimedia animasi visual berdasarkan tiga aspek iaitu aspek isi kandungan, aspek interaksi dan aspek persembahan telah memeperolehi skor min yang tinggi bagi ketiga-tiga aspek tersebut. Dapatan kajian ini menggambarkan penggunaan koswer multimedia animasi visual dapat membantu meningkatkan pencapaian Matematik di dalam bilik darjah terutama yang tidak melibatkan pengiraan

    Classification of Several Skin Cancer Types Based on Autofluorescence Intensity of Visible Light to Near Infrared Ratio

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    Skin cancer is a Malignant growth on the skin caused by many factors. The most common skin cancers are Basal Cell Cancer (BCC) and Squamous Cell Cancer (SCC). This research uses a discriminant analysis to classify some tissues of skin cancer based on criterion number of independent variables. An independent variable is variation of excitation light sources (LED lamp), filters, and sensors to measure autofluorescence intensity (IAF) of visible light to near infrared (VIS/NIR) ratio of paraffin embedded tissue biopsy from BCC, SCC, and Lipoma. From the result of discriminant analysis, it is known that the discriminant function is determined by 4 (four) independent variables i.e., blue LED-red filter, blue LED-yellow filter, UV LED-blue filter, and UV LED-yellow filter. The accuracy of discriminant in classifying the analysis of three skin cancer tissues is 100%

    CP-odd Phase Correlations and Electric Dipole Moments

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    We revisit the constraints imposed by electric dipole moments (EDMs) of nucleons and heavy atoms on new CP-violating sources within supersymmetric theories. We point out that certain two-loop renormalization group corrections induce significant mixing between the basis-invariant CP-odd phases. In the framework of the constrained minimal supersymmetric standard model (CMSSM), the CP-odd invariant related to the soft trilinear A-phase at the GUT scale, theta_A, induces non-trivial and distinct CP-odd phases for the three gaugino masses at the weak scale. The latter give one-loop contributions to EDMs enhanced by tan beta, and can provide the dominant contribution to the electron EDM induced by theta_A. We perform a detailed analysis of the EDM constraints within the CMSSM, exhibiting the reach, in terms of sparticle spectra, which may be obtained assuming generic phases, as well as the limits on the CP-odd phases for some specific parameter points where detailed phenomenological studies are available. We also illustrate how this reach will expand with results from the next generation of experiments which are currently in development.Comment: 31 pages, 21 eps figures; v2: additional remarks on 2-loop threshold corrections and references added; v3: typos corrected, to appear in Phys. Rev.
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