242 research outputs found

    Pemetaan Nilai Percepatan Tanah Maksimum dengan Metode Deterministic Seismic Hazard Analysis di Lokasi Pembangunan Observatorium Nasional Desa Bitobe Kecamatan Amfoang Tengah Kabupaten Kupang

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    Penelitian menggunakan metode HVSR (Horizontal to Vertical Spectral Ratio) telah dilakukan untuk memetakan daerah yang rawan terhadap gempa bumi di Desa Bitobe. Tujuan dari penelitian ini adalah mengetahui nilai periode dominan tanah dan percepatan tanah maksimum, serta untuk membuat peta PGA dan juga peta Mikrozonasi. Pengambilan data dilakukan pada 45 titik dengan jarak antar titik ± 250 m dari titik satu ke titik lainnya dengan waktu perekaman selama ± 20 menit menggunakan TDS tipe 303S. Data yang diperoleh diolah menggunakan software Datapro, Geopsy, Surfer 13, dan Google Earth. Hasil pengolahan data diperoleh nilai frekuensi dominan (). Parameter ini digunakan untuk meghitung nilai PGA menggunakan persamaan empiris Kanai dengan data katalog gempa bumi dari tahun 1966-2016. Metode Mc.Guirre dan Esteva hanya menggunakan data katalog gempa saja dalam menghitung PGA. Berdasarkan hasil penelitian, didapatkan bahwa nilai frekuensi dominan berkisar antara 0,273 Hz – 17,887 Hz. Nilai percepatan tanah maksimum berdasarkan persamaan empiris Kanai berkisar antara 32,319 gal – 261,178 gal, Mc.Guirre berkisar antara 128,215 gal – 134,862 gal dan Esteva berkisar antara 147,359 gal – 156,007 gal. Hasil dari ketiga persamaan ini memiliki perbedaan dengan peta hazard gempa Indonesia. Kata kunci: HVSR, Mikrozonasi, Kanai, Mc.Guirre, Esteva, Bitob

    PEMETAAN NILAI PERCEPATAN TANAH MAKSIMUM DENGAN METODE DETERMINISTIC SEISMIC HAZARD ANALYSIS DI LOKASI PEMBANGUNAN OBSERVATORIUM NASIONAL DESA BITOBE KECAMATAN AMFOANG TENGAH KABUPATEN KUPANG

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    ABSTRAK Penelitian menggunakan metode HVSR (Horizontal to Vertical Spectral Ratio) telah dilakukan untuk memetakan daerah yang rawan terhadap gempa bumi di Desa Bitobe. Tujuan dari penelitian ini adalah mengetahui nilai periode dominan tanah dan percepatan tanah maksimum, serta untuk membuat peta PGA dan juga peta Mikrozonasi. Pengambilan data dilakukan pada 45 titik dengan jarak antar titik ± 250 m dari titik satu ke titik lainnya dengan waktu perekaman selama ± 20 menit menggunakan TDS tipe 303S. Data yang diperoleh diolah menggunakan software Datapro, Geopsy, Surfer 13, dan Google Earth. Hasil pengolahan data diperoleh nilai frekuensi dominan (). Parameter ini digunakan untuk meghitung nilai PGA menggunakan persamaan empiris Kanai dengan data katalog gempa bumi dari tahun 1966-2016. Metode Mc.Guirre dan Esteva hanya menggunakan data katalog gempa saja dalam menghitung PGA. Berdasarkan hasil penelitian, didapatkan bahwa nilai frekuensi dominan berkisar antara 0,273 Hz – 17,887 Hz. Nilai percepatan tanah maksimum berdasarkan persamaan empiris Kanai berkisar antara 32,319 gal – 261,178 gal, Mc.Guirre berkisar antara 128,215 gal – 134,862 gal dan Esteva berkisar antara 147,359 gal – 156,007 gal. Hasil dari ketiga persamaan ini memiliki perbedaan dengan peta hazard gempa Indonesia. Kata kunci: HVSR, Mikrozonasi, Kanai, Mc.Guirre, Esteva, Bitobe ABSTRACT The research using HVSR (Horizontal to Vertical Spectral Ratio) has been carried out to map the disturb areas to earthquakes in Bitobe village. The aims of this research are to determine the values of soil dominant frequency and the peak ground acceleration than make PGA map and also microzonation map. Data were collected at 45 points with the distance between points ± 250 meters from one point to the other with ± 20 minutes of recording time used TDS 303S type. The data were processed using software Datapro, Geopsy, Surfer 13, and Google Earth. The result of data processing was dominant frequency value (). This parameter was used to calculate the peak ground acceleration with Kanai empirical equations. The earthquakes catalog data were used from 1966-2016. Mc.Guirre and Esteva method only used the earthquakes catalog data to calculated the PGA. According to this research, it was obtained that the values of the dominant frequency was about 0,273 Hz – 17,887 Hz. The values of peak ground acceleration based on Kanai empirical equations about 32,319 gal – 261,178 gal, Mc.Guirre about 128,215 gal – 134,862 gal and Esteva about 147,359 gal – 156,007 gal. The result of this third equations have different with the earthquakes hazard map of Indonesia. Key Words: HVSR, Microzonation, Kanai, Mc.Guirre, Esteva, Bitob

    Regional Analysis of the Magnetization Transfer Ratio of the Brain in Mild Alzheimer Disease and Amnestic Mild Cognitive Impairment

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    BACKGROUND AND PURPOSE: Manually drawn VOI-based analysis shows a decrease in magnetization transfer ratio in the hippocampus of patients with Alzheimer disease. We investigated with whole-brain voxelwise analysis the regional changes of the magnetization transfer ratio in patients with mild Alzheimer disease and patients with amnestic mild cognitive impairment. MATERIALS AND METHODS: Twenty patients with mild Alzheimer disease, 27 patients with amnestic mild cognitive impairment, and 30 healthy elderly control subjects were examined with high-resolution T1WI and 3-mm-thick magnetization transfer images. Whole-brain voxelwise analysis of magnetization transfer ratio maps was performed by use of Statistical Parametric Mapping 8 software and was supplemented by the analysis of the magnetization transfer ratio in FreeSurfer parcellation-derived VOIs. RESULTS: Voxelwise analysis showed 2 clusters of significantly decreased magnetization transfer ratio in the left hippocampus and amygdala and in the left posterior mesial temporal cortex (fusiform gyrus) of patients with Alzheimer disease as compared with control subjects but no difference between patients with amnestic mild cognitive impairment and either patients with Alzheimer disease or control subjects. VOI analysis showed that the magnetization transfer ratio in the hippocampus and amygdala was significantly lower (bilaterally) in patients with Alzheimer disease when compared with control subjects (ANOVA with Bonferroni correction, at P < .05). Mean magnetization transfer ratio values in the hippocampus and amygdala in patients with amnestic mild cognitive impairment were between those of healthy control subjects and those of patients with mild Alzheimer disease. Support vector machine-based classification demonstrated improved classification performance after inclusion of magnetization transfer ratio-related features, especially between patients with Alzheimer disease versus healthy subjects. CONCLUSIONS: Bilateral but asymmetric decrease of magnetization transfer ratio reflecting microstructural changes of the residual GM is present not only in the hippocampus but also in the amygdala in patients with mild Alzheimer disease

    Correlation of HER2 status between primary tumors and corresponding circulating tumor cells in advanced breast cancer patients

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    International audienceBiocharacterization of circulating tumor cells (CTCs) in the peripheral blood of advanced breast cancer (ABC) patients may represent a real-time tumor biopsy. We assessed HER2 status on CTCs from blood samples of ABC patients. CTCs were separated and stained using the CellSearch System. HER2 status was assessed by immunofluorescence and, when technically feasible, by fluorescence in situ hybridization. Blood samples were obtained from 66 ABC patients. Forty patients had a positive CTC sample (61%) and of these, 15 (37%) had HER2 + CTCs. We found non-concordant results in 32% of cases: 29% (8/28) of HER2-negative primary tumors had HER2-positive CTCs and 42% (5/12) of HER2-positive primary tumors had HER2-negative CTCs ( = 0.278). Our study suggests that a subset of patients with HER2-negative primary tumors develops HER2-positive CTCs during disease progression

    Network segregation in a model of misinformation and fact checking

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    Misinformation under the form of rumor, hoaxes, and conspiracy theories spreads on social media at alarming rates. One hypothesis is that, since social media are shaped by homophily, belief in misinformation may be more likely to thrive on those social circles that are segregated from the rest of the network. One possible antidote is fact checking which, in some cases, is known to stop rumors from spreading further. However, fact checking may also backfire and reinforce the belief in a hoax. Here we take into account the combination of network segregation, finite memory and attention, and fact-checking efforts. We consider a compartmental model of two interacting epidemic processes over a network that is segregated between gullible and skeptic users. Extensive simulation and mean-field analysis show that a more segregated network facilitates the spread of a hoax only at low forgetting rates, but has no effect when agents forget at faster rates. This finding may inform the development of mitigation techniques and overall inform on the risks of uncontrolled misinformation online

    A Linear Fragment of Unacylated Ghrelin (UAG6−13) Protects Against Myocardial Ischemia/Reperfusion Injury in Mice in a Growth Hormone Secretagogue Receptor-Independent Manner

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    Unacylated ghrelin (UAG), the most abundant form of ghrelin in circulation, has been shown to exert cardioprotective effect in experimental cardiopathies. The present study aimed to investigate the cardioprotective effect of a linear bioactive fragment of UAG against myocardial ischemia-induced injury and dysfunction in C57BL/6 wild type mice and the mechanisms involved. Treatments were administered at doses of 100 (UAG), 1,000 and 3,000 (UAG6−13) nmol/kg at 12 h interval during 14 days prior to 30 min left coronary artery ligation and reperfusion for a period of 6 or 48 h. The infarct area was decreased in a dose-dependent manner at 48 h of reperfusion, with a reduction of 54% at the highest dose of UAG6−13 tested. Myocardial hemodynamics were improved as demonstrated by an increase in cardiac output, maximum first derivative of left ventricular pressure, and preload recruitable stroke work, a load-independent contractility index. Six hours after reperfusion, circulating levels of IL-6 and TNF-α pro-inflammatory cytokines were reduced, and the effect was maintained at 48 h for TNF-α. 5â€Č AMP-activated protein kinase (AMPK) was activated, while acetyl-CoA carboxylase (ACC) activity was inhibited, along with a decrease in apoptotic protein levels. In isolated hearts, the effect of UAG6−13 was unaffected by the presence of D-Lys3-GHRP-6, a ghrelin receptor (GHSR1a) antagonist, suggesting that the peptide acted through a GHSR1a-independent pathway. The results support the therapeutic application of UAG bioactive peptide fragments against myocardial ischemia/reperfusion injury

    Debunking in a world of tribes

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    Social media aggregate people around common interests eliciting collective framing of narratives and worldviews. However, in such a disintermediated environment misinformation is pervasive and attempts to debunk are often undertaken to contrast this trend. In this work, we examine the effectiveness of debunking on Facebook through a quantitative analysis of 54 million users over a time span of five years (Jan 2010, Dec 2014). In particular, we compare how users usually consuming proven (scientific) and unsubstantiated (conspiracy-like) information on Facebook US interact with specific debunking posts. Our findings confirm the existence of echo chambers where users interact primarily with either conspiracy-like or scientific pages. However, both groups interact similarly with the information within their echo chamber. Then, we measure how users from both echo chambers interacted with 50,220 debunking posts accounting for both users consumption patterns and the sentiment expressed in their comments. Sentiment analysis reveals a dominant negativity in the comments to debunking posts. Furthermore, such posts remain mainly confined to the scientific echo chamber. Only few conspiracy users engage with corrections and their liking and commenting rates on conspiracy posts increases after the interaction

    Arnold diffusion for a complete family of perturbations

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    In this work we illustrate the Arnold diffusion in a concrete example — the a priori unstable Hamiltonian system of 2 + 1/2 degrees of freedom H(p, q, I, f, s) = p2/2+ cos q - 1 + I2/2 + h(q, f, s; e) — proving that for any small periodic perturbation of the form h(q, f, s; e) = e cos q (a00 + a10 cosf + a01 cos s) (a10a01 Âż 0) there is global instability for the action. For the proof we apply a geometrical mechanism based on the so-called scattering map. This work has the following structure: In the first stage, for a more restricted case (I* ~ p/2”, ” = a10/a01), we use only one scattering map, with a special property: the existence of simple paths of diffusion called highways. Later, in the general case we combine a scattering map with the inner map (inner dynamics) to prove the more general result (the existence of instability for any ”). The bifurcations of the scattering map are also studied as a function of ”. Finally, we give an estimate for the time of diffusion, and we show that this time is primarily the time spent under the scattering map.Peer ReviewedPostprint (published version
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