146 research outputs found

    Diagnosa Kesulitan Belajar Berbasis Jenis Pengetahuan pada Materi Akuntansi Penjualan Kredit

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    Hasil tes diagnostik sebagai sarana untuk mengetahui kelemahan belajar siswa dapat digunakan sebagai petunjuk kegiatan belajar remedial yang terarah. Penelitian ini bertujuan mengidentifikasi dan mengungkap sebab-sebab kesulitan belajar akuntansi pada siklus akuntansi dagang pada transaksi penjualan kredit metode pencatatan periodik kasus perolehan laba. Data yang dipakai untuk menganalisis tes diagnostik disajikan dalam profil kesulitan belajar akuntansi dagang dari berbagai dimensi jenis pengetahuan. Hasil penelitian menunjukkan bahwa siswa berkesulitan pada dimensi fakta: 1) “Menyebutkan nominal laba yang diperoleh” ,pada dimensi konsep: 1) “Syarat Penjualan: 3/10, n/30” dan 2) “Pengelompokkan Akun Nominal dan Riil” , pada dimensi prinsip: 1) “Pengidentifikasian Perolehan Laba/Rugi Perusahaan pada Neraca Lajur “dan 2) “Posting Jurnal Penutup ke Buku Besar”, dan pada dimensi prosedur: 1) “Jurnal Penerimaan Kas” pada kasus bukti transaksi “Bukti Kas Masuk”, 2) “Buku Besar Pembantu Piutang”, 3) Neraca lajur mengenai “Penulisan Identitas Perusahaan pada Neraca Lajur”, “Penyelesaian kolom L/R”, dan “Identifikasi Perolehan Laba/Rugi” dan 3) “Posting Jurnal Penutup ke Buku Besar”

    The TRENDS High-Contrast Imaging Survey. VII. Discovery of a Nearby Sirius-like White Dwarf System (HD 169889)

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    Monitoring the long-term radial velocity (RV) and acceleration of nearby stars has proven an effective method for directly detecting binary and substellar companions. Some fraction of nearby RV trend systems are expected to be comprised of compact objects that likewise induce a systemic Doppler signal. In this paper, we report the discovery of a white dwarf companion found to orbit the nearby (π=28.297±0.066\pi = 28.297 \pm 0.066 mas) G9 V star HD 169889. High-contrast imaging observations using NIRC2 at Keck and LMIRCam at the LBT uncover the (ΔH=9.76±0.16\Delta H = 9.76 \pm 0.16, ΔL=9.60±0.03\Delta L' = 9.60 \pm 0.03) companion at an angular separation of 0.8'' (28 au). Thirteen years of precise Doppler observations reveal a steep linear acceleration in RV time series and place a dynamical constraint on the companion mass of M0.369±0.010MM \geq 0.369 \pm 0.010 M_{\odot}. This "Sirius-like" system adds to the census of white dwarf companions suspected to be missing in the solar neighborhood.Comment: Accepted to Ap

    Speckle statistics in adaptive optics images at visible wavelengths

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    Residual speckles in adaptive optics (AO) images represent a well-known limitation on the achievement of the contrast needed for faint source detection. Speckles in AO imagery can be the result of either residual atmospheric aberrations, not corrected by the AO, or slowly evolving aberrations induced by the optical system. We take advantage of the high temporal cadence (1 ms) of the data acquired by the System for Coronagraphy with High-order Adaptive Optics from R to K bands-VIS forerunner experiment at the Large Binocular Telescope to characterize the AO residual speckles at visible wavelengths. An accurate knowledge of the speckle pattern and its dynamics is of paramount importance for the application of methods aimed at their mitigation. By means of both an automatic identification software and information theory, we study the main statistical properties of AO residuals and their dynamics. We therefore provide a speckle characterization that can be incorporated into numerical simulations to increase their realism and to optimize the performances of both real-time and postprocessing techniques aimed at the reduction of the speckle noise

    The Multiplicity of M-Dwarfs in Young Moving Groups

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    We image 104 newly identified low-mass (mostly M-dwarf) pre-main sequence members of nearby young moving groups with Magellan Adaptive Optics (MagAO) and identify 27 binaries with instantaneous projected separation as small as 40 mas. 15 were previously unknown. The total number of multiple systems in this sample including spectroscopic and visual binaries from the literature is 36, giving a raw multiplicity rate of at least 354+5%35^{+5}_{-4}\% for this population. In the separation range of roughly 1 - 300 AU in which infrared AO imaging is most sensitive, the raw multiplicity rate is at least 244+5%24^{+5}_{-4}\% for binaries resolved by the MagAO infrared camera (Clio). The M-star sub-sample of 87 stars yields a raw multiplicity of at least 304+5%30^{+5}_{-4}\% over all separations, 214+5%21^{+5}_{-4}\% for secondary companions resolved by Clio from 1 to 300 AU (234+5%23^{+5}_{-4}\% for all known binaries in this separation range). A combined analysis with binaries discovered by the Search for Associations Containing Young stars shows that multiplicity fraction as a function of mass and age over the range of 0.2 to 1.2 MM_\odot and 10 - 200 Myr appears to be linearly flat in both parameters and across YMGs. This suggests that multiplicity rates are largely set by 100 Myr without appreciable evolution thereafter. After bias corrections are applied, the multiplicity fraction of low-mass YMG members (<0.6M< 0.6 M_\odot) is in excess of the field.Comment: 25 page

    The effect of otic melanocyte destruction on auditory and vestibular function: A study on vitiligo patients

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    The hallmark of vitiligo is the disappearance of melanocytes from the skin. As a result, of melanocytes presence in the auditory and vestibular apparatus, the involvement of these systems in vitiligo which targets the melanocytes of the whole body is possible; suggesting that vitiligo is a systemic disease rather than a purely cutaneous problem. A total of 21 patients with vitiligo were enrolled in this study. A group of 20 healthy subjects served as a control group. Pure tone audiometry (PTA), auditory brainstem responses (ABR) and vestibular evoked myogenic potentials (VEMP) were carried out in all participants. High frequency sensory neural hearing loss was seen in 8 (38.09) patients. ABR analysis revealed 10 (47.61) had an abnormal increase in latency of wave III, and 6 (28.57) had an abnormal prolongation of IPL I-III, however, regarding our VEMP findings, there were no recorded responses on left ear of 1 (4.76) patient and latency of p13 was prolonged in 5(23.80) patients. There was no correlation between ages, duration of disease, and any of the recorded parameters (P>0.05). In the present survey, we highlighted the auditory and vestibular involvement in vitiligo patients. © 2015 Tehran University of Medical Sciences. All rights reserved

    Gene expression profiling and network analysis of peripheral blood monocytes in a chronic model of allergic asthma

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    The Aspergillus fumigatus mouse model of asthma mimics the characteristics of human fungal asthma, including local and systemic inflammation. Monocyte/macrophage lineage cells direct innate immune responses and guide adaptive responses. To identify gene expression changes in peripheral blood monocytes in the context of fungal allergy, mice were exposed to systemic and intranasal inoculations of fungal antigen (sensitized), and naïve and sensitized animals were challenged intratracheally with live A. fumigatus conidia. Microarray analysis of blood monocytes from allergic versus non-allergic mice showed ≥ twofold modulation of 45 genes. Ingenuity pathway analysis revealed a network of these genes involved in antigen presentation, inflammation, and immune cell trafficking. These data show that allergen sensitization and challenge affects gene expression in peripheral monocytes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79085/1/j.1348-0421.2010.00242.x.pd

    Large Binocular Telescope Interferometer Adaptive Optics: On-sky performance and lessons learned

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    The Large Binocular Telescope Interferometer is a high contrast imager and interferometer that sits at the combined bent Gregorian focus of the LBT's dual 8.4~m apertures. The interferometric science drivers dictate 0.1'' resolution with 10310410^3-10^4 contrast at 10 μm10~\mu m, while the 4 μm4~\mu m imaging science drivers require even greater contrasts, but at scales >>0.2''. In imaging mode, LBTI's Adaptive Optics system is already delivering 4 μm4~\mu m contrast of 10410510^4-10^5 at 0.30.750.3''-0.75'' in good conditions. Even in poor seeing, it can deliver up to 90\% Strehl Ratio at this wavelength. However, the performance could be further improved by mitigating Non-Common Path Aberrations. Any NCPA remedy must be feasible using only the current hardware: the science camera, the wavefront sensor, and the adaptive secondary mirror. In preliminary testing, we have implemented an ``eye doctor'' grid search approach for astigmatism and trefoil, achieving 5\% improvement in Strehl Ratio at 4 μm4~\mu m, with future plans to test at shorter wavelengths and with more modes. We find evidence of NCPA variability on short timescales and discuss possible upgrades to ameliorate time-variable effectsComment: Published in Proceedings of SPIE, vol 9148: Adaptive Optics Systems I

    Imaging protoplanets: observing transition disks with non-redundant masking

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    Transition disks, protoplanetary disks with inner clearings, are promising objects in which to directly image forming planets. The high contrast imaging technique of non-redundant masking is well posed to detect planetary mass companions at several to tens of AU in nearby transition disks. We present non-redundant masking observations of the T Cha and LkCa 15 transition disks, both of which host posited sub-stellar mass companions. However, due to a loss of information intrinsic to the technique, observations of extended sources (e.g. scattered light from disks) can be misinterpreted as moving companions. We discuss tests to distinguish between these two scenarios, with applications to the T Cha and LkCa 15 observations. We argue that a static, forward-scattering disk can explain the T Cha data, while LkCa 15 is best explained by multiple orbiting companions.Comment: SPIE conference proceedin
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