401 research outputs found
Herschel dust emission as a probe of starless cores mass: MCLD 123.5+24.9 of the Polaris Flare
We present newly processed archival Herschel images of molecular cloud MCLD
123.5+24.9 in the Polaris Flare. This cloud contains five starless cores. Using
the spectral synthesis code Cloudy, we explore uncertainties in the derivation
of column densities, hence, masses of molecular cores from Herschel data. We
first consider several detailed grain models that predict far-IR grain
opacities. Opacities predicted by the models differ by more than a factor of
two, leading to uncertainties in derived column densities by the same factor.
Then we consider uncertainties associated with the modified blackbody fitting
process used by observers to estimate column densities. For high column density
clouds (N(H) 10 cm), this fitting technique can
underestimate column densities by about a factor of three. Finally, we consider
the virial stability of the five starless cores in MCLD 123.5+24.9. All of
these cores appear to have strongly sub-virial masses, assuming, as we argue,
that CO line data provide reliable estimates of velocity dispersions.
Evidently, they are not self-gravitating, so it is no surprise that they are
starless.Comment: ApJ, Accepted. Minor typographical errors corrected and figures 6 & 7
updated in v
Artifact removal techniques for lung CT images in lung cancer detection
Lung Cancer in today’s world is one of the major widespread dangerous diseases which is the subject of maximum deaths every year. Accurate detection of lung cancer could boost the endurance rate. Medical image processing has a significant impact on the recognition of lung tumors using Computer Tomography (CT) scan images. Images from a CT scan are widely used because they provide comprehensive imaging of tumor progression inside the lungs. Although different types of noise might be experienced while doing CT scans, producing it a monotonous task for recognizing tumors in the lung. Elimination of noise in CT images is a challenging task for medical diagnoses. The presence of noise in an image is inevitable. Hence reducing noise from the CT scan image is critical for further analysis. Hence various filtering techniques have been used that denoise and enhance the image and help in further evaluation of CT images for accurate lung cancer detection. This paper analyses the noises of different kinds in the CT images and different noise removal techniques which help in improving the accuracy of segmentation and feature extraction as they remove unwanted noise and contribute to the accurate detection of lung cancer. The various filtering methods are analyzed with salt along with pepper noise and speckle noise. The performances of different filters are computed in terms of metrics for evaluation like PSNR, SSIM, MSE, and SNR. The experimental results show that the median filter is more efficient in comparison to other filtering methods in eliminating noises that exist in lung CT images by owning fewer MSE values of 214.8522, high SNR value of 19.36304, SSIM value 0.595997, and high PSNR value of 24.80941
Organogenesis from cotyledon and hypocotyl-derived explants of japhara (Bixa orellana L.)
A protocol for direct organogenesis in Bixa orellana (pink flowers variety) has been developed with significant organogenic response from rooted hypocotyls, hypocotyl segments, and cotyledonary leaf explants on Murashige and Skoog (MS) medium supplemented
with 2.0 mg L–1 thidiazuron and 0.25% coconut water or 7.0 mg L–1 N6-Benzyladenine and 0.1 mg L–1 a-naphthalene acetic acid. Thidiazuron in combination with coconut water promoted higher organogenic response in rooted hypocotyls. Similarly direct organogenesis was noticed from hypocotyls, cotyledonary leaf explants and shoot tip explants on half MS medium with 0.25 mg L–1 N6-Benzyladenine (BA) and 0.5 mg L–1 indole-3-acetic acid (IAA). Best shoot elongation of shoot buds was achieved in the presence
of 1.5 mg L–1 (BA) + 1.0 mg L–1indole-3-butyric acid (IBA). The in vitro rooting of microshoots was good in the presence of 3.0 mg L–1 (IBA). Seventy percent of rooted plants survived after acclimatization
Monte Carlo Radiation Transport for Astrophysical Transients Powered by Circumstellar Interaction
In this paper, we introduce \texttt{SuperLite}, an open-source Monte Carlo
radiation transport code designed to produce synthetic spectra for
astrophysical transient phenomena affected by circumstellar interaction.
\texttt{SuperLite} utilizes Monte Carlo methods for semi-implicit,
semi-relativistic radiation transport in high-velocity shocked outflows,
employing multi-group structured opacity calculations. The code enables rapid
post-processing of hydrodynamic profiles to generate high-quality spectra that
can be compared with observations of transient events, including superluminous
supernovae, pulsational pair-instability supernovae, and other peculiar
transients. We present the methods employed in \texttt{SuperLite} and compare
the code's performance to that of other radiative transport codes, such as
\texttt{SuperNu} and CMFGEN. We show that \texttt{SuperLite} has successfully
passed standard Monte Carlo radiation transport tests and can reproduce spectra
of typical supernovae of Type Ia, Type IIP and Type IIn.Comment: Accepted for publication at the Astrophysics Journa
Tris(methyl 3-oxobutanoato-κ2 O,O′)aluminium(III)
In the title compound, [Al(C5H7O3)3], three acac-type ligands (methyl 3-oxobutanoate anions) chelate to the aluminium(III) cation in a slightly distorted AlO6 octahedral coordination geometry. Electron delocalization occurs within the chelating rings
A 9-Bit Flash Analog to Digital Convertor
Need constantly exists for converters with higher resolution, faster conversion speed and lower power dissipation. High-speed analog to digital converters (ADC’s) have been based on flash architecture, because all comparators sample the analog input voltage simultaneously, this ADC is thus inherently fast. Unfortunately, flash ADC requires 2N - 1 comparators to convert N bit digital code from an analog sample. This makes flash ADC’s unsuitable for high-resolution applications. This paper demonstrates a simple technique to reduce comparator requirement of 9-bit flash ADC that requires as few as 256 comparators for 9-bit conversion. In this approach, the analog input range is partitioned into 256 quantization cells, separated by 255 boundary points. A 8-bit binary code 00000000 to 11111111 is assigned to each cell. A 9-bit flash converter requires 512 comparators, while proposed technique reduces number of comparator requirements to 256 for 9-bit conversion
Four novel mutations in patients from the Middle East with the infantile form of GM1-gangliosidosis.
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