The Discovery of Soft X-ray Loud Broad Absorption Line Quasars

It is been known for more than a decade that BALQSOs (broad absorption line quasars) are highly attenuated in the X-ray regime compared to other quasars, especially in the soft band ($<$ 1 keV). Using X-ray selection techniques we have found "soft X-ray loud" BALQSOs that, by definition, have soft X-ray (0.3 keV) to UV ($3000 \AA$) flux density ratios that are higher than typical nonBAL radio quiet quasars. Our sample of 3 sources includes one LoBALQSO (low ionization BALQSO) which are generally considered to be the most highly attenuated in the X-rays. The three QSOs are the only known BALQSOs that have X-ray observations that are consistent with no intrinsic soft X-ray absorption. The existence of a large X-ray luminosity and the hard ionizing continuum that it presents to potential UV absorption gas is in conflict with the ionization states that are conducive to line driving forces within BAL winds (especially for the LoBALs).Comment: To appear in ApJ Letter

Discovery of a 3.6-hr Eclipsing Luminous X-Ray Binary in the Galaxy NGC 4214

We report the discovery of an eclipsing X-ray binary with a 3.62-hr period within 24" of the center of the dwarf starburst galaxy NGC 4214. The orbital period places interesting constraints on the nature of the binary, and allows for a few very different interpretations. The most likely possibility is that the source lies within NGC 4214 and has an X-ray luminosity of up to 7 e38 ergs/s. In this case the binary may well be comprised of a naked He-burning donor star with a neutron-star accretor, though a stellar-mass black-hole accretor cannot be completely excluded. There is no obvious evidence for a strong stellar wind in the X-ray orbital light curve that would be expected from a massive He star; thus, the mass of the He star should be <3-4 solar masses. If correct, this would represent a new class of very luminous X-ray binary -- perhaps related to Cyg X-3. Other less likely possibilities include a conventional low-mass X-ray binary that somehow manages to produce such a high X-ray luminosity and is apparently persistent over an interval of years; or a foreground AM Her binary of much lower luminosity that fortuitously lies in the direction of NGC 4214. Any model for this system must accommodate the lack of an optical counterpart down to a limiting magnitude of 22.6 in the visible.Comment: 7 pages, ApJ accepted versio

Alginate/hydrophobic HPMC (60L) particulate systems: new matrix for controlled release of diclofenac potassium

This work is focused on the development of a new particulate drug delivery system using sodium alginate (SA) and modified hydrophobic hydroxyl propyl methyl cellulose (HPMC, 60L grade) containing diclofenac as a model drug molecule for intestinal drug prolonged release. Diclofenac loaded HPMC-SA beads have been developed by ion exchange methods and were characterized by encapsulation efficiency, drug release profile, swelling and matrix erosion rate. Matrix swelling of calcium alginate beads induced by phosphate buffer ends up in erosion and destruction. However, for HPMC-SA beads do not lead to complete erosion, which may be the main cause of diclofenac retention within the matrix. The release of diclofenac potassium is negligible at acidic pH, while is complete in 5-6 h when pH is raised up to 7.4. The alginate/HPMC ratio controls the release rate of the drug. The drug release is decreased as the polymer concentration is increased from 2.5 to 3.5 %. Release kinetic study was done to understand the correlation between the formulations. The results show that drug release is diffusion controlled and it is Anomalous type which means combined process of both swelling and erosion of polymer.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Topic Segmentation in the Wild: Towards Segmentation of Semi-structured & Unstructured Chats

Breaking down a document or a conversation into multiple contiguous segments based on its semantic structure is an important and challenging problem in NLP, which can assist many downstream tasks. However, current works on topic segmentation often focus on segmentation of structured texts. In this paper, we comprehensively analyze the generalization capabilities of state-of-the-art topic segmentation models on unstructured texts. We find that: (a) Current strategies of pre-training on a large corpus of structured text such as Wiki-727K do not help in transferability to unstructured texts. (b) Training from scratch with only a relatively small-sized dataset of the target unstructured domain improves the segmentation results by a significant margin.Comment: NeurIPS 2022 : ENLS

UGC 7069: The largest ring galaxy

We find that UGC 7069 is the largest ring galaxy known to date. In this Letter, we present a multiwavelength study of this galaxy (combining radio, 2MASS, optical and ultraviolet data). The ring of UGC 7069, whose diameter measures ~115 kpc, is also warped at its edges. The nucleus appears double-peaked and hosts a possible LINER. The ultraviolet data indicate a strong blue colour and suggest that UGC 7069 is a starburst galaxy. We also present N-body simulation results, which indicate that galaxy collisions can produce such huge rings. Large inclination angles between the target and the intruder galaxy may account for the formation of warped rings. Multiwavelength observations are highly essential to constrain our simulation results, which will address the formation and evolution of such a rare galaxy.Comment: 6 pages, 5 figures, MNRAS Letters, in pres

Topic Segmentation of Semi-Structured and Unstructured Conversational Datasets using Language Models

Breaking down a document or a conversation into multiple contiguous segments based on its semantic structure is an important and challenging problem in NLP, which can assist many downstream tasks. However, current works on topic segmentation often focus on segmentation of structured texts. In this paper, we comprehensively analyze the generalization capabilities of state-of-the-art topic segmentation models on unstructured texts. We find that: (a) Current strategies of pre-training on a large corpus of structured text such as Wiki-727K do not help in transferability to unstructured conversational data. (b) Training from scratch with only a relatively small-sized dataset of the target unstructured domain improves the segmentation results by a significant margin. We stress-test our proposed Topic Segmentation approach by experimenting with multiple loss functions, in order to mitigate effects of imbalance in unstructured conversational datasets. Our empirical evaluation indicates that Focal Loss function is a robust alternative to Cross-Entropy and re-weighted Cross-Entropy loss function when segmenting unstructured and semi-structured chats.Comment: Accepted to IntelliSys 2023. arXiv admin note: substantial text overlap with arXiv:2211.1495

Alginate/hydrophobic HPMC (60L) particulate systems: new matrix for controlled release of diclofenac potassium

This work is focused on the development of a new particulate drug delivery system using sodium alginate (SA) and modified hydrophobic hydroxyl propyl methyl cellulose (HPMC, 60L grade) containing diclofenac as a model drug molecule for intestinal drug prolonged release. Diclofenac loaded HPMC-SA beads have been developed by ion exchange methods and were characterized by encapsulation efficiency, drug release profile, swelling and matrix erosion rate. Matrix swelling of calcium alginate beads induced by phosphate buffer ends up in erosion and destruction. However, for HPMC-SA beads do not lead to complete erosion, which may be the main cause of diclofenac retention within the matrix. The release of diclofenac potassium is negligible at acidic pH, while is complete in 5-6 h when pH is raised up to 7.4. The alginate/HPMC ratio controls the release rate of the drug. The drug release is decreased as the polymer concentration is increased from 2.5 to 3.5 %. Release kinetic study was done to understand the correlation between the formulations. The results show that drug release is diffusion controlled and it is Anomalous type which means combined process of both swelling and erosion of polymer.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Optical Spectroscopy of the environment of a ULX in NGC 7331

Optical photometric and spectroscopic data are presented that show an association of an ultraluminous X-ray source in NGC 7331 with a young star cluster of mass 1.1e5 solar masses and age 4.25 Myr. If the ULX is part of the bright stellar cluster, then the mass of the progenitor of the compact accretor must have been greater than about 40-50 solar masses in order to already have evolved through the supernova stage to a compact object. The companion star is also likely an evolved massive star. The emission line spectrum of the nebula surrounding the cluster can be interpreted as a result of photoionization by the cluster OB stars with an additional source of shock excitation producing strong [SII], [OI] and NII lines. This additional source appears to be as much as five times more powerful than the supernovae and stellar winds in the cluster can provide. Additional mechanical energy input associated with the ULX itself can help explain the residual shock excited line luminosities of the emission region.Comment: 17 pages, accepted to Ap