424 research outputs found

    Aplikasi E-learning di SMP Negeri 46 Bandung

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    SMPN 46 Bandung merupakan sekolah SMP negeri yang di bangun pada tahun 1994 dan mulai beroperasi pada tahun 1995. Pada sekolah SMPN 46 Bandung ada beberapa Masalah yang dihadapi dalam proses pembelajaran, diantaranya Proses kegiatan belajar mengajar didalam kelas sangat terbatas singkatnya waktu dan banyaknya materi yang akan diajarkan membuat proses belajar mengajar kurang optimal, Siswa hanya mendapatkan materi pelajaran dari guru maupun referensi buku di perpustakaan sekolah, sehingga terjadi keterbatasan tempat dan waktu untuk mengakses. Siswa juga kurang dapat mengeksplorasi kemampuan mereka dalam melakukan pemanfaatan koneksi internet. Metode penelitian yang digunakan adalah metode deskriptif. Pengembangan atau pendekatan aplikasi yang digunakan dalam skripsi ini menggunakan metode pengembangan Prototype. Sedangkan alat-alat yang digunakan dalam analisa perancangan sistem adalah Flowmap, Diagram konteks, Data Flow Diagram, ERD, Tabel Relasi, sedangkan implementasi dari perancangan sistem adalah bahasa pemograman PHP dan My SQL sebagai database. Pembuatan Aplikasi E-learning ini dapat membantu proses pembelajaran dalam mendapatkan materi pelajaran, mengirim tugas, ujian secara online juga berkomunikasi dengan guru maupun sesama siswa. Aplikasi E-learning di SMP Negeri 46 Bandung dibuat untuk kelancaran dalam proses pembelajaran. kemudian merancang sistem database serta membuat program aplikasi untuk mendukung system informasi E-learning

    A robust, semi-automated approach for counting cementum increments imaged with synchrotron X-ray computed tomography

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    Cementum, the tissue attaching mammal tooth roots to the periodontal ligament, grows appositionally throughout life, displaying a series of circum-annual incremental features. These have been studied for decades as a direct record of chronological lifespan. The majority of previous studies on cementum have used traditional thin-section histological methods to image and analyse increments. However, several caveats have been raised in terms of studying cementum increments in thin-sections. Firstly, the limited number of thin-sections and the two-dimensional perspective they impart provide an incomplete interpretation of cementum structure, and studies often struggle or fail to overcome complications in increment patterns that complicate or inhibit increment counting. Increments have been repeatedly shown to both split and coalesce, creating accessory increments that can bias increment counts. Secondly, identification and counting of cementum increments using human vision is subjective, and it has led to inaccurate readings in several experiments studying individuals of known age. Here, we have attempted to optimise a recently introduced imaging modality for cementum imaging; X-ray propagation-based phase-contrast imaging (PPCI). X-ray PPCI was performed for a sample of rhesus macaque (Macaca mulatta) lower first molars (n = 10) from a laboratory population of known age. PPCI allowed the qualitative identification of primary/annual versus intermittent secondary increments formed by splitting/coalescence. A new method for semi-automatic increment counting was then integrated into a purpose-built software package for studying cementum increments, to count increments in regions with minimal complications. Qualitative comparison with data from conventional cementochronology, based on histological examination of tissue thin-sections, confirmed that X-ray PPCI reliably and non-destructively records cementum increments (given the appropriate preparation of specimens prior to X-ray imaging). Validation of the increment counting algorithm suggests that it is robust and provides accurate estimates of increment counts. In summary, we show that our new increment counting method has the potential to overcome caveats of conventional cementochronology approaches, when used to analyse three-dimensional images provided by X-ray PPCI.Peer reviewe

    Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements

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    Measurements of 142Nd isotope signatures in Archean rocks are a powerful tool to investigate the earliest silicate differentiation events on Earth. Here, we introduce a new analytical protocol that allows high precision radiogenic and mass-independent Nd isotope measurements by MC-ICP-MS. To validate our method, we have measured well-characterized ∼3.72 to ∼3.8 Ga samples from the Eoarchean Itsaq Gneiss Complex and associated supracrustal belts, as well as Mesoarchean greenstones and a Proterozoic dike in SW Greenland, including lithostratigraphic units that were previously analyzed for 142-143Nd isotope systematics, by both TIMS and MC-ICP-MS. Our μ142Nd values for ∼3.72 to ∼3.8 Ga rocks from the Isua region range from +9.2 ± 2.6 to +13.2 ± 1.1 ppm and are in good agreement with previous studies. Using coupled 142,143Nd/144Nd isotope systematics from our data for ∼3.8 Ga mafic-ultramafic successions from the Isua region, we can confirm previous age constraints on the earliest silicate differentiation events with differentiation age of 4.390−0.060+0.045 Ga. Moreover, we can resolve a statistically significant decrease of 142Nd/144Nd isotope compositions in the ambient mantle of SW Greenland that already started to commence by Eoarchean time, between ∼3.8 Ga (μ142Nd = +13.0 ± 1.1) and ∼ 3.72 Ga (μ142Nd = +9.8 ± 1.0). Even lower but homogeneous μ142Nd values of +3.8 ± 1.1 are found in ∼3.4 Ga mantle-derived rocks from the Ameralik dike swarms. Our study reveals that ε143Nd(i) and εHf(i) values of Isua rocks scatter more than it would be expected from a single stage differentiation event as implied from nearly uniform μ142Nd values, suggesting that the previously described decoupling of Hf and Nd isotopes is not a primordial magma ocean signature. Instead, we conclude that some of second stage processes like younger mantle depletion events or recycling of subducted material affected the 147Smsingle bond143Nd isotope systematics. The preservation of pristine whole-rock isochrons largely rules out a significant disturbance by younger alteration events. Based on isotope and trace element modelling, we argue that the temporal evolution of coupled 142,143Nd/144Nd isotope compositions in the ambient mantle beneath the Isua rocks is best explained by the progressive admixture of material to the Isua mantle source that must have had present-day-like μ142Nd compositions. In contrast, Mesoarchean mafic rocks from the ∼3.08 Ga Ivisaartoq greenstone belt and the 2.97 Ga inner Ameralik Fjord region as well as a 2.0 Ga Proterozoic dike within that region all have higher μ142Nd values as would be expected from our simple replenishment model. This argues for reworking of older Isua crustal material that carried elevated μ142Nd compositions

    Cacos de resistências: artefatos em vidros lascados por pessoas escravizadas na Charqueada São João, Pelotas, RS

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    The objects have the possibility to present alternative perspectives to the colonialist discourses on the slavery. As well, representations about the past participate in contemporary political agendas. Our research intends to approach the practices of resistance developed by enslaved people in a coercive situation. In this sense, we analyze the archeological glasses from the São João Beef Jerky plantation (Pelotas, RS) as a contribution to a material understanding of the daily life of the enslaved people, especially concerning the production of utilitarian tools and the possibilities of participation in the maintenance of the sacred of African origin, following the interpretations from the people of saint. These analyses were presented at a museological exhibition at the Beef Jerky Plantation, promoting these objects to continue being materialities of resistance.Os artefatos arqueológicos nos permitem apresentar perspectivas alternativas aos discursos colonialistas sobre a escravização. Por sua vez, as representações sobre o passado participam de agendas políticas contemporâneas. Nossa pesquisa pretende abordar as práticas de resistências que desenvolviam as pessoas escravizadas frente à situação de coerção. Nesse sentido, analisamos os vidros escavados na Charqueada São João (Pelotas, RS) como uma contribuição a um entendimento material da vida cotidiana de escravizados e escravizadas no século XIX. O foco está na produção de artefatos utilitários no âmbito da resistência e na manutenção do sagrado. Discutimos também os motivos contextuais e simbólicos que levariam à manufatura desses artefatos em vidro por pessoas escravizadas na Charqueada São João. Tais resultados foram apresentados numa exposição museológica temporária na Charqueada, aonde retornaram ao seu status como materialidades de resistência

    Why do men have worse COVID-19-related outcomes? A systematic review and meta-analysis with sex adjusted for age

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    We aimed to study the mechanism behind worse coronavirus disease-19 (COVID-19) outcomes in men and whether the differences between sexes regarding mortality as well as disease severity are influenced by sex hormones. To do so, we used age as a covariate in the meta-regression and subgroup analyses. This was a systematic search and meta-analysis of observational cohorts reporting COVID-19 outcomes. The PubMed (Medline) and Cochrane Library databases were searched. The primary outcome was COVID-19-associated mortality and the secondary outcome was COVID-19 severity. The study was registered at PROSPERO: 42020182924. For mortality, men had a relative risk of 1.36 (95%CI: 1.17 to 1.59; I² 63%, P for heterogeneity <0.01) compared to women. Age was not a significant covariate in meta-analysis heterogeneity (P=0.393) or subgroup analysis. For disease severity, being male was associated with a relative risk of 1.29 (95%CI: 1.19 to 1.40; I² 48%, P for heterogeneity <0.01) compared to the relative risk of women. Again, age did not influence the outcomes of the metaregression (P=0.914) or subgroup analysis. Men had a higher risk of COVID-19 mortality and severity regardless of age, decreasing the odds of hormonal influences in the described outcomes

    Characterisation of Conventional 87Sr/86Sr Isotope Ratios in Cement, Limestone and Slate Reference Materials Based on an Interlaboratory Comparison Study

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    An interlaboratory comparison (ILC) was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the so-called conventional method for determining 87Sr/86Sr isotope ratios. Four cements (VDZ 100a, VDZ 200a, VDZ 300a, IAG OPC-1), one limestone (IAG CGL ML-3) and one slate (IAG OU-6) reference materials were selected, covering a wide range of naturally occurring Sr isotopic signatures. Thirteen laboratories received aliquots of these six reference materials together with a detailed technical protocol. The consensus values for the six reference materials and their associated measurement uncertainties were obtained by applying a Gaussian, linear mixed effects model fitted to all the measurement results. By combining the consensus values and their uncertainties with an uncertainty contribution for potential heterogeneity, reference values ranging from 0.708134 mol mol-1 to 0.729778 mol mol-1 were obtained with relative expanded uncertainties of ≤ 0.007 %. This study represents an ILC on conventional 87Sr/86Sr isotope ratios, within which metrological principles were considered and the compatibility of measurement results obtained by MC-ICP-MS and by MC-TIMS is demonstrated. The materials characterised in this study can be used as reference materials for validation and quality control purposes and to estimate measurement uncertainties in conventional 87Sr/86Sr isotope ratio measurement

    Evolution of Hematophagous Habit in Triatominae (Heteroptera: Reduviidae)

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    All members of Triatominae subfamily (Heteroptera: Reduviidae), potential vectors of Trypanosoma cruzi, etiologic agent of the Chagas disease, feed on blood. Through evolution, these bugs have fixed special morphological, physiological, and behavioral aptations (adaptations and exaptations) adequate to feed on blood. Phylogeny suggests that triatomines evolved from predator reduvids which in turn descended from phytophagous hemipterans. Some pleisiomorphic traits developed by the reduvid ancestors of the triatomines facilitated and modeled hematophagy in these insects. Among them, mouthparts, saliva composition, enzymes, and digestive symbionts are the most noticeable. However, the decisive step that allowed the shift from predation to hematophagy was a change of behavior. The association of a predator reduvid with nesting vertebrate (≈110 to 32 Ma) permitted the shift from an arthropod prey to a vertebrate host. In this work, we review the phylogeny and dispersion of triatomines and the current controversy over the monophyly or polyphyly of this group. We also discuss how these insects were able to overcome, and even have taken advantage of, diverse ancestral and physical barriers to adapt to sucking blood of nidicolous vertebrates

    Evolution of Hematophagous Habit in Triatominae (Heteroptera: Reduviidae)

    Get PDF
    All members of Triatominae subfamily (Heteroptera: Reduviidae), potential vectors of Trypanosoma cruzi, etiologic agent of the Chagas disease, feed on blood. Through evolution, these bugs have fixed special morphological, physiological, and behavioral aptations (adaptations and exaptations) adequate to feed on blood. Phylogeny suggests that triatomines evolved from predator reduvids which in turn descended from phytophagous hemipterans. Some pleisiomorphic traits developed by the reduvid ancestors of the triatomines facilitated and modeled hematophagy in these insects. Among them, mouthparts, saliva composition, enzymes, and digestive symbionts are the most noticeable. However, the decisive step that allowed the shift from predation to hematophagy was a change of behavior. The association of a predator reduvid with nesting vertebrate (≈110 to 32 Ma) permitted the shift from an arthropod prey to a vertebrate host. In this work, we review the phylogeny and dispersion of triatomines and the current controversy over the monophyly or polyphyly of this group. We also discuss how these insects were able to overcome, and even have taken advantage of, diverse ancestral and physical barriers to adapt to sucking blood of nidicolous vertebrates
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