1,170 research outputs found

    Does the Debris Disk around HD 32297 Contain Cometary Grains?

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    We present an adaptive optics imaging detection of the HD 32297 debris disk at L' (3.8 \microns) obtained with the LBTI/LMIRcam infrared instrument at the LBT. The disk is detected at signal-to-noise per resolution element ~ 3-7.5 from ~ 0.3-1.1" (30-120 AU). The disk at L' is bowed, as was seen at shorter wavelengths. This likely indicates the disk is not perfectly edge-on and contains highly forward scattering grains. Interior to ~ 50 AU, the surface brightness at L' rises sharply on both sides of the disk, which was also previously seen at Ks band. This evidence together points to the disk containing a second inner component located at \lesssim 50 AU. Comparing the color of the outer (50 <r< r/AU <120< 120) portion of the disk at L' with archival HST/NICMOS images of the disk at 1-2 \microns allows us to test the recently proposed cometary grains model of Donaldson et al. 2013. We find that the model fails to match the disk's surface brightness and spectrum simultaneously (reduced chi-square = 17.9). When we modify the density distribution of the model disk, we obtain a better overall fit (reduced chi-square = 2.9). The best fit to all of the data is a pure water ice model (reduced chi-square = 1.06), but additional resolved imaging at 3.1 \microns is necessary to constrain how much (if any) water ice exists in the disk, which can then help refine the originally proposed cometary grains model.Comment: Accepted to ApJ January 13, 2014. 12 pages (emulateapj style), 9 figures, 1 tabl

    Opinion Poll: Big Data Implementation of Unstructured Data Analytics of Social Network Reviews Using Sentiment Analysis SVM

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    Recent systems developed are dependent on user feedbacks or opinions. These feedbacks or opinions are generated in volumes everyday which are difficult to filter and analyse. We propose Sentiment based analysis is the major key in categorizing the user\u27s Feedback. In thispaper, we study the processing of all the reviews posted in an online shopping application and classify them using SVM. We use big data to analyze the vast amounts of data generated. User reviews are the input to the Big Data HDFS System. Data are stored in the Data Nodes. Index is maintained in the Name Node. Reviews are analyzed using Sentiment Analysis and Positive Negative Tweets are classified. Also products are recommended based on the previous purchases and group notification is sent to all the customers in a group

    The Gray Needle: Large Grains in the HD 15115 Debris Disk from LBT/PISCES/Ks and LBTI/LMIRcam/L' Adaptive Optics Imaging

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    We present diffraction-limited \ks band and \lprime adaptive optics images of the edge-on debris disk around the nearby F2 star HD 15115, obtained with a single 8.4 m primary mirror at the Large Binocular Telescope. At \ks band the disk is detected at signal-to-noise per resolution element (SNRE) \about 3-8 from \about 1-2\fasec 5 (45-113 AU) on the western side, and from \about 1.2-2\fasec 1 (63-90 AU) on the east. At \lprime the disk is detected at SNRE \about 2.5 from \about 1-1\fasec 45 (45-90 AU) on both sides, implying more symmetric disk structure at 3.8 \microns . At both wavelengths the disk has a bow-like shape and is offset from the star to the north by a few AU. A surface brightness asymmetry exists between the two sides of the disk at \ks band, but not at \lprime . The surface brightness at \ks band declines inside 1\asec (\about 45 AU), which may be indicative of a gap in the disk near 1\asec. The \ks - \lprime disk color, after removal of the stellar color, is mostly grey for both sides of the disk. This suggests that scattered light is coming from large dust grains, with 3-10 \microns -sized grains on the east side and 1-10 \microns dust grains on the west. This may suggest that the west side is composed of smaller dust grains than the east side, which would support the interpretation that the disk is being dynamically affected by interactions with the local interstellar medium.Comment: Apj-accepted March 27 2012; minor correction

    Hybrid fuzzy PI controlled multi-input DC/DC converter for electric vehicle application

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    Power electronic interface with its effective control scheme plays a major role in the utilization of energy sources for electric vehicle application. For this purpose, a hybrid fuzzy PI based control scheme for a multiple input converter (MIC) topology is proposed. The proposed hybrid fuzzy PI controller includes a conventional PI controller at steady state and fuzzy PI at transient state. Also, the proposed control design helps in tracking a predefined speed profile to have complete realization of electric vehicle. Detailed simulation study and performance comparisons with conventional controller are performed. The results show that the developed control scheme is robust providing bidirectional power management, fast tracking capability with less steady state error, better dynamic response by enhancing the flexibility and proper utilization of energy sources. Simulation in MATLAB/SIMULINK environment is carried out to verify the performance of the multi-input converter with the developed control scheme. An experimental set-up is constructed to validate the same

    First Light LBT AO Images of HR 8799 bcde at 1.65 and 3.3 Microns: New Discrepancies between Young Planets and Old Brown Dwarfs

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    As the only directly imaged multiple planet system, HR 8799 provides a unique opportunity to study the physical properties of several planets in parallel. In this paper, we image all four of the HR 8799 planets at H-band and 3.3 microns with the new LBT adaptive optics system, PISCES, and LBTI/LMIRCam. Our images offer an unprecedented view of the system, allowing us to obtain H and 3.3$ micron photometry of the innermost planet (for the first time) and put strong upper-limits on the presence of a hypothetical fifth companion. We find that all four planets are unexpectedly bright at 3.3 microns compared to the equilibrium chemistry models used for field brown dwarfs, which predict that planets should be faint at 3.3 microns due to CH4 opacity. We attempt to model the planets with thick-cloudy, non-equilibrium chemistry atmospheres, but find that removing CH4 to fit the 3.3 micron photometry increases the predicted L' (3.8 microns) flux enough that it is inconsistent with observations. In an effort to fit the SED of the HR 8799 planets, we construct mixtures of cloudy atmospheres, which are intended to represent planets covered by clouds of varying opacity. In this scenario, regions with low opacity look hot and bright, while regions with high opacity look faint, similar to the patchy cloud structures on Jupiter and L/T transition brown-dwarfs. Our mixed cloud models reproduce all of the available data, but self-consistent models are still necessary to demonstrate their viability.Comment: Accepted to Ap

    A Review of Privacy Preserving Techniques inWireless Sensor Network

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    This paper represents a review of privacy preserving techniques in wireless sensor network. Wireless sensor networks are not secure. To preserve privacy of wireless sensor network various techniques are discovered. A lot of work has been done to address challenges faced to preserve privacy of wireless sensor network. In this paper we represent a research on privacy preserving techniques used in location privacy, data privacy and network privacy. This paper should provide help for further research in privacy preservation in wireless sensor network. Keywords: Context privacy, data privacy, source location privac

    A study of histomorphological profile of triple-negative breast cancer

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    BACKGROUND: Triple-negative breast cancer (TNBC) is defined by the lack of expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (Her2) expression. It is characterized by distinct clinical, morphological and molecular features and associated with aggressive clinical course and poor prognosis. PURPOSE: This study is aimed at examining the clinicopathologic features of triple- negative breast cancer and at evaluating the expression of CK 5/6 and epidermal growth factor receptor (EGFR) among 50 cases of triple-negative breast cancers and to correlate the expression of basal markers with the clinicopathologic prognostic parameters. MATERIALS AND METHODS: Fifty female patients with triple-negative breast cancer were studied for clinical and pathological features and by immunohistochemistry for CK 5/6 and EGFR expression. Statistical analysis was done using descriptive analysis and correlation tests. RESULTS: The mean age of the patients was 50.4 years. Infiltrating ductal carcinoma IDC, NOS type was the predominant histological type (46/50 [92%]). The commonest histologic grade was grade II (27/50 [55%]). Tumour necrosis was seen in 70% of the cases (35/50). 72% of the cases were positive for at least one of the basal markers CK 5/6 and EGFR. We observed a statistically significant correlation between tumour size and lymph node metastasis. CONCLUSION: The triple-negativity of tumours should not be used as a marker for basal-like tumours. The use of CK 5/6 and EGFR can define basal phenotype. A majority of the cases show EGFR expression. Hence TNBCs could be treated with EGFR targeted therapies
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