76 research outputs found

    Penerapan Keterampilan Proses Untuk Meningkatkan Hasil Belajar Siswa Pada Mata Pelajaran Sains (Sifat Benda) Di Kelas IV SDN 2 Karamat

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    Pelaksanaan penelitian ini dilatarbelakangi rendahnya hasil belajar pada mata pelajaran sains siswa kelas IV SDN 2 Karamat yang ditunjukkan dengan hasil belajar siswa pada tahun ajaran 2012/2013 yaitu 62. Penelitian ini bertujuan untuk meningkatkan hasil belajar siswa pada mata pelajaran sains di kelas IV SDN 2 karamat. Subyek penelitian berjumlah 16 orang. Penelitian ini adalah penelitian tindakan kelas yang terdiri atas dua siklus. Rancangan penelitian mengacu pada modifikasi diagram Kemmis dan Mc. Taggart, yaitu 1) Perencanaan tindakan, 2) Pelaksanaan tindakan, 3) Observasi, dan 4) Refleksi. Teknik pengumpulan data yang digunakan adalah lembar observasi guru dan siswa, LKS, serta tes hasil belajar siswa. Hasil penelitian menunjukkan terjadi peningkatan hasil belajar, dari siklus I ke siklus II. Peningkatan tersebut dibuktikan dengan hasil analisis tes hasil belajar siswa yang diperoleh pada siklus I adalah ketuntasan klasikal sebesar 75%, daya serap klasikal 68,2%, dan rata-rata hasil belajar 68. Rata-rata hasil belajar pada siklus I mengalami peningkatan sebesar 8,8% dari hasil yang diperoleh pada pratindakan, serta aktivitas siswa dalam kategori cukup dan aktivitas guru rata-rata dalam kategori baik. Pada siklus II diperoleh hasil yang lebih baik lagi dari siklus I yaitu persentase ketuntasan klasikal 87,5%, daya serap klasikal mencapai 78,2% dan rata-rata hasil belajar adalah 78, serta aktivitas siswa berada dalam kategori sangat baik dan aktivitas guru dalam kategori sangat baik. Berdasarkan hasil penelitian menunjukkan bahwa penerapan keterampilan proses dapat meningkatkan hasil belajar siswa pada mata pelajaran sains (sifat-sifat benda) di kelas IV SDN 2 Karamat

    Functional role of PGAM5 multimeric assemblies and their polymerization into filaments.

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    PGAM5 is a mitochondrial protein phosphatase whose genetic ablation in mice results in mitochondria-related disorders, including neurodegeneration. Functions of PGAM5 include regulation of mitophagy, cell death, metabolism and aging. However, mechanisms regulating PGAM5 activation and signaling are poorly understood. Using electron cryo-microscopy, we show that PGAM5 forms dodecamers in solution. We also present a crystal structure of PGAM5 that reveals the determinants of dodecamer formation. Furthermore, we observe PGAM5 dodecamer assembly into filaments both in vitro and in cells. We find that PGAM5 oligomerization into a dodecamer is not only essential for catalytic activation, but this form also plays a structural role on mitochondrial membranes, which is independent of phosphatase activity. Together, these findings suggest that modulation of the oligomerization of PGAM5 may be a regulatory switch of potential therapeutic interest

    Penerapan Keterampilan Proses Untuk Meningkatkan Hasil Belajar Siswa Pada Mata Pelajaran Sains (Sifat Benda) di Kelas IV SDN 2 Karamat

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    Pelaksanaan penelitian ini dilatarbelakangi rendahnya hasil belajar pada mata pelajaran sains siswa kelas IV SDN 2 Karamat yang ditunjukkan dengan hasil belajar siswa pada tahun ajaran 2012/2013 yaitu 62. Penelitian ini bertujuan untuk meningkatkan hasil belajar siswa pada mata pelajaran sains di kelas IV SDN 2 karamat. Subyek penelitian berjumlah 16 orang. Penelitian ini adalah penelitian tindakan kelas yang terdiri atas dua siklus. Rancangan penelitian mengacu pada modifikasi diagram Kemmis dan Mc. Taggart, yaitu 1) Perencanaan tindakan, 2) Pelaksanaan tindakan, 3) Observasi, dan 4) Refleksi. Teknik pengumpulan data yang digunakan adalah lembar observasi guru dan siswa, LKS, serta tes hasil belajar siswa. Hasil penelitian menunjukkan terjadi peningkatan hasil belajar, dari siklus I ke siklus II. Peningkatan tersebut dibuktikan dengan hasil analisis tes hasil belajar siswa yang diperoleh pada siklus I adalah ketuntasan klasikal sebesar 75%, daya serap klasikal 68,2%, dan rata-rata hasil belajar 68. Rata-rata hasil belajar pada siklus I mengalami peningkatan sebesar 8,8% dari hasil yang diperoleh pada pratindakan, serta aktivitas siswa dalam kategori cukup dan aktivitas guru rata-rata dalam kategori baik. Pada siklus II diperoleh hasil yang lebih baik lagi dari siklus I yaitu persentase ketuntasan klasikal 87,5%, daya serap klasikal mencapai 78,2% dan rata-rata  hasil  belajar adalah  78, serta aktivitas siswa berada dalam kategori sangat baik dan aktivitas guru dalam kategori sangat baik. Berdasarkan hasil penelitian menunjukkan bahwa penerapan keterampilan proses dapat meningkatkan hasil belajar siswa pada mata pelajaran sains (sifat-sifat benda) di kelas IV SDN 2 Karamat. Kata kunci: Keterampilan Proses, Hasil Belajar Sisw

    MCPIP1 functions as a safeguard of early embryonic development

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    Monocyte chemoattractant protein-induced protein 1 (MCPIP1), also called Regnase-1, is an RNase that has been described as a key negative modulator of inflammation. MCPIP1 also controls numerous tumor-related processes, such as proliferation, apoptosis and differentiation. In this study, we utilized a zebrafish model to investigate the role of Mcpip1 during embryogenic development. Our results demonstrated that during embryogenesis, the expression of the zc3h12a gene encoding Mcpip1 undergoes dynamic changes. Its transcript levels gradually increase from the 2-cell stage to the spherical stage and then decrease rapidly. We further found that ectopic overexpression of wild-type Mcpip1 but not the catalytically inactive mutant form resulted in an embryonic lethal phenotype in zebrafish embryos (24 hpf). At the molecular level, transcriptomic profiling revealed extensive changes in the expression of genes encoding proteins important in the endoplasmic reticulum stress response and in protein folding as well as involved in the formation of primary germ layer, mesendoderm and endoderm development, heart morphogenesis and cell migration. Altogether, our results demonstrate that the expression of zc3h12a must be tightly controlled during the first cell divisions of zebrafish embryos and that a rapid decrease in its mRNA expression is an important factor promoting proper embryo development

    A comprehensive framework for assessing the accuracy and uncertainty of global above-ground biomass maps

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    Over the past decade, several global maps of above-ground biomass (AGB) have been produced, but they exhibit significant differences that reduce their value for climate and carbon cycle modelling, and also for national estimates of forest carbon stocks and their changes. The number of such maps is anticipated to increase because of new satellite missions dedicated to measuring AGB. Objective and consistent methods to estimate the accuracy and uncertainty of AGB maps are therefore urgently needed. This paper develops and demonstrates a framework aimed at achieving this. The framework provides a means to compare AGB maps with AGB estimates from a global collection of National Forest Inventories and research plots that accounts for the uncertainty of plot AGB errors. This uncertainty depends strongly on plot size, and is dominated by the combined errors from tree measurements and allometric models (inter-quartile range of their standard deviation (SD) = 30–151 Mg ha−1). Estimates of sampling errors are also important, especially in the most common case where plots are smaller than map pixels (SD = 16–44 Mg ha−1). Plot uncertainty estimates are used to calculate the minimum-variance linear unbiased estimates of the mean forest AGB when averaged to 0.1∘. These are used to assess four AGB maps: Baccini (2000), GEOCARBON (2008), GlobBiomass (2010) and CCI Biomass (2017). Map bias, estimated using the differences between the plot and 0.1∘ map averages, is modelled using random forest regression driven by variables shown to affect the map estimates. The bias model is particularly sensitive to the map estimate of AGB and tree cover, and exhibits strong regional biases. Variograms indicate that AGB map errors have map-specific spatial correlation up to a range of 50–104 km, which increases the variance of spatially aggregated AGB map estimates compared to when pixel errors are independent. After bias adjustment, total pantropical AGB and its associated SD are derived for the four map epochs. This total becomes closer to the value estimated by the Forest Resources Assessment after every epoch and shows a similar decrease. The framework is applicable to both local and global-scale analysis, and is available at https://github.com/arnanaraza/PlotToMap. Our study therefore constitutes a major step towards improved AGB map validation and improvement

    A comprehensive framework for assessing the accuracy and uncertainty of global above-ground biomass maps

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    International audienceOver the past decade, several global maps of above-ground biomass (AGB) have been produced, but they exhibit significant differences that reduce their value for climate and carbon cycle modelling, and also for national estimates of forest carbon stocks and their changes. The number of such maps is anticipated to increase because of new satellite missions dedicated to measuring AGB. Objective and consistent methods to estimate the accuracy and uncertainty of AGB maps are therefore urgently needed. This paper develops and demonstrates a framework aimed at achieving this. The framework provides a means to compare AGB maps with AGB estimates from a global collection of National Forest Inventories and research plots that accounts for the uncertainty of plot AGB errors. This uncertainty depends strongly on plot size, and is dominated by the combined errors from tree measurements and allometric models (inter-quartile range of their standard deviation (SD) = 30–151 Mg ha−1). Estimates of sampling errors are also important, especially in the most common case where plots are smaller than map pixels (SD = 16–44 Mg ha−1). Plot uncertainty estimates are used to calculate the minimum-variance linear unbiased estimates of the mean forest AGB when averaged to 0.1∘. These are used to assess four AGB maps: Baccini (2000), GEOCARBON (2008), GlobBiomass (2010) and CCI Biomass (2017). Map bias, estimated using the differences between the plot and 0.1∘ map averages, is modelled using random forest regression driven by variables shown to affect the map estimates. The bias model is particularly sensitive to the map estimate of AGB and tree cover, and exhibits strong regional biases. Variograms indicate that AGB map errors have map-specific spatial correlation up to a range of 50–104 km, which increases the variance of spatially aggregated AGB map estimates compared to when pixel errors are independent. After bias adjustment, total pantropical AGB and its associated SD are derived for the four map epochs. This total becomes closer to the value estimated by the Forest Resources Assessment after every epoch and shows a similar decrease. The framework is applicable to both local and global-scale analysis, and is available at https://github.com/arnanaraza/PlotToMap. Our study therefore constitutes a major step towards improved AGB map validation and improvement

    The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

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    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

    A clathrin-dependent pathway leads to KRas signaling on late endosomes en route to lysosomes

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    Ras proteins are small guanosine triphosphatases involved in the regulation of important cellular functions such as proliferation, differentiation, and apoptosis. Understanding the intracellular trafficking of Ras proteins is crucial to identify novel Ras signaling platforms. In this study, we report that epidermal growth factor triggers Kirsten Ras (KRas) translocation onto endosomal membranes (independently of calmodulin and protein kinase C phosphorylation) through a clathrin-dependent pathway. From early endosomes, KRas but not Harvey Ras or neuroblastoma Ras is sorted and transported to late endosomes (LEs) and lysosomes. Using yellow fluorescent protein–Raf1 and the Raichu-KRas probe, we identified for the first time in vivo–active KRas on Rab7 LEs, eliciting a signal output through Raf1. On these LEs, we also identified the p14–MP1 scaffolding complex and activated extracellular signal-regulated kinase 1/2. Abrogation of lysosomal function leads to a sustained late endosomal mitogen-activated protein kinase signal output. Altogether, this study reveals novel aspects about KRas intracellular trafficking and signaling, shedding new light on the mechanisms controlling Ras regulation in the cell
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