138 research outputs found

    Penerapan Strategi 3-2-1 Berbantuan Refutation Text Untuk Mereduksi Miskonsepsi Siswa Pada Materi Fluida Statis

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    This pre-experimental research was aimed to investigate the use of 3-2-1 reading strategy assisted by refutation text to reduce students\u27 misconceptions on subtopic static fluid in SMA Negeri 1 Teluk Keramat. Sample of this research was students from XI IPA 1 class who choosen by intact group random sampling technique. Diagnostic test which consist of 18 multiple choice question with open reasoning was used as research instrument to asses students conceptions. Based on the results, the highest students\u27 misconceptions in pretest (100%) and posttest (20,51%) was that the concept of buoyant force. The average decrease of misconceptions for each concepts were 82,56%. Students\u27 conceptions had changed statistically significant after the instruction. Students achieved average normalized gain 0,82 (relatively high). The 3-2-1 reading strategy assisted by refutation text is expected to be used as an alternative remediation activities to overcome the misconceptions that experienced by students

    Peningkatan Aktivitas dan Hasil Belajar Fisika melalui Strategi Pembelajaran dan Lks Berbasis Predict-observe-explain di SMP

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    The purpose of this research is to improve students\u27 learning activity and the result through LKS and learning strategy based on Predict-Observe-Explain (POE) on Archimedes Law in class VIIIA of SMP Negeri 2 Sanggau. This research is a Classroom Action Research (CAR) which done in two cycle with two meetings. Every cycle has four steps, planning, implementing, observing, and reflecting. The subject of this research are 30 students from the destined class. In collecting the data the researcher used observation paper and test item. The result shows that there is an improvement in students\u27 learning activity in the active stage and very active stage from 1st cycle to the 2nd cycle that is 6,66%, from 66,67% to 73,33%. This improvement affecting the result if students\u27 learning activity to reach the KKM from the 1st cycle to the 2nd cycle that is 3,33%, from 90% to 93,33%

    Cosmic Microwave Background Anisotropy with Cosine-Type Quintessence

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    We study the Cosmic Microwave Background (CMB) anisotropies produced by cosine-type quintessence models. In our analysis, effects of the adiabatic and isocurvature fluctuations are both taken into account. For purely adiabatic fluctuations with scale invariant spectrum, we obtain a stringent constraint on the model parameters using the CMB data from COBE, BOOMERanG and MAXIMA. Furthermore, it is shown that isocurvature fluctuations have significant effects on the CMB angular power spectrum at low multipoles in some parameter space, which may be detectable in future satellite experiments. Such a signal may be used to test the cosine-type quintessence models.Comment: 21 pages, 9 figure

    Structural basis for the adaptation and function of chlorophyll f in photosystem I

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    Chlorophylls (Chl) play pivotal roles in energy capture, transfer and charge separation in photosynthesis. Among Chls functioning in oxygenic photosynthesis, Chl f is the most red-shifted type first found in a cyanobacterium Halomicronema hongdechloris. The location and function of Chl f in photosystems are not clear. Here we analyzed the high-resolution structures of photosystem I (PSI) core from H. hongdechloris grown under white or far-red light by cryo-electron microscopy. The structure showed that, far-red PSI binds 83 Chl a and 7 Chl f, and Chl f are associated at the periphery of PSI but not in the electron transfer chain. The appearance of Chl f is well correlated with the expression of PSI genes induced under far-red light. These results indicate that Chl f functions to harvest the far-red light and enhance uphill energy transfer, and changes in the gene sequences are essential for the binding of Chl f

    Cosmic Density Perturbations from Late-Decaying Scalar Condensations

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    We study the cosmic density perturbations induced from fluctuation of the amplitude of late-decaying scalar condensations (called \phi) in the scenario where the scalar field \phi once dominates the universe. In such a scenario, the cosmic microwave background (CMB) radiation originates to decay products of the scalar condensation and hence its anisotropy is affected by the fluctuation of \phi. It is shown that the present cosmic density perturbations can be dominantly induced from the primordial fluctuation of \phi, not from the fluctuation of the inflaton field. This scenario may change constraints on the source of the density perturbations, like inflation. In addition, a correlated mixture of adiabatic and isocurvature perturbations may arise in such a scenario; possible signals in the CMB power spectrum are discussed. We also show that the simplest scenario of generating the cosmic density perturbations only from the primordial fluctuation of \phi (i.e., so-called ``curvaton'' scenario) is severely constrained by the current measurements of the CMB angular power spectrum if correlated mixture of the adiabatic and isocurvature perturbations are generated.Comment: 31pages, 14figure

    Genome-wide association study of an unusual dolphin mortality event reveals candidate genes for susceptibility and resistance to cetacean morbillivirus

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    Infectious diseases are significant demographic and evolutionary drivers of populations, but studies about the genetic basis of disease resistance and susceptibility are scarce in wildlife populations. Cetacean morbillivirus (CeMV) is a highly contagious disease that is increasing in both geographic distribution and incidence, causing unusual mortality events (UME) and killing tens of thousands of individuals across multiple cetacean species worldwide since the late 1980s. The largest CeMV outbreak in the Southern Hemisphere reported to date occurred in Australia in 2013, where it was a major factor in a UME, killing mainly young Indo-Pacific bottlenose dolphins (Tursiops aduncus). Using cases (nonsurvivors) and controls (putative survivors) from the most affected population, we carried out a genome-wide association study to identify candidate genes for resistance and susceptibility to CeMV. The genomic data set consisted of 278,147,988 sequence reads and 35,493 high-quality SNPs genotyped across 38 individuals. Association analyses found highly significant differences in allele and genotype frequencies among cases and controls at 65 SNPs, and Random Forests conservatively identified eight as candidates. Annotation of these SNPs identified five candidate genes (MAPK8, FBXW11, INADL, ANK3 and ACOX3) with functions associated with stress, pain and immune responses. Our findings provide the first insights into the genetic basis of host defence to this highly contagious disease, enabling the development of an applied evolutionary framework to monitor CeMV resistance across cetacean species. Biomarkers could now be established to assess potential risk factors associated with these genes in other CeMV-affected cetacean populations and species. These results could also possibly aid in the advancement of vaccines against morbilliviruses.Kimberley C. Batley, Jonathan Sandoval‐Castillo, Catherine M. Kemper, Catherine R. M. Attard, Nikki Zanardo, Ikuko Tomo, Luciano B. Beheregaray, Luciana M. Mölle

    Cetacean <i>Morbillivirus</i>: Current knowledge and future directions

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    We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USA and Australia. It represents a distinct species within the Morbillivirus genus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemically infected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported
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