Spectroscopic investigations and measurements of certain ARC jet parameters

The NASA/JSC Atmospheric Reentry Materials and Structures Evaluation Facility (ARMSEF) was intensively and extensively involved in ground testing of spacecraft materials and thermal protection systems (TPS) in simulated reentry conditions. Ground experiments on surface catalytic efficiency of such TPS requires a knowledge of the flow system in the arc jet. In the work described, spectroscopic diagnostic techniques are used to determine the free stream constituents. Specifically, the emission spectrum of the free stream constituents was obtained and the species therein identified. A laser system was added on, which will give the added capacity of studying the arc jet flow using Laser Raman Spectroscopy (LRS). The LRS technique will complement information obtained from the emission spectra. A short list of further work that can be done in the area of spectroscopic investigations on the arc jet is mentioned

Contribution of N₂O emissions to the atmosphere from Indian monsoonal estuaries

Estuaries are known to contribute a significant amount of nitrous oxide (N2O) to the atmosphere; however, the contribution from the Indian estuaries is unknown. We made an attempt to estimate emissions of N2O from the Indian estuaries by collecting samples from 28 major and minor estuaries along the Indian coast during the wet and dry periods. The N2O was mostly saturated in all measured Indian estuaries during the study period (72–631 %), with exceptionally high saturation in the Ponniyaar estuary (5902%) during the wet period. The N2O saturation displayed a strong relation with dissolved inorganic nitrogen (DIN; nitrate+nitrite and ammonium), ammonium and dissolved oxygen saturation, suggesting that nitrification is the major source of N2O in the Indian estuaries. The negative relation between salinity and N2O saturation suggests inner estuaries are a strong source compared to outer estuaries. The annual mean N2O saturation (204 ± 137%) and fluxes (1.3 μmol N2O m−2 d−1) in the Indian estuaries were significantly less than European estuaries (271% and ∼2.7 μmol N2O m−2 d−1, respectively). The estimation of flux of N2O from the European estuaries was also biased due to the inclusion of an exceptionally high supersaturation value from a small UK estuary, Colne (2645%). However, low N2O saturation and fluxes in the Indian estuaries were related to mean low concentration of DIN that led to low nitrification rates compared to world estuaries. Despite India ranking second in artificial fertilizers use, high flushing rates during the wet period reduce residence time leading to less modification within the estuary

Surgery for post-vitrectomy cataract

BACKGROUND: Cataract formation or acceleration can occur after intraocular surgery, especially following vitrectomy, a surgical technique for removing the vitreous which is used in the treatment of disorders that affect the posterior segment of the eye. The underlying problem that led to vitrectomy may limit the benefit from cataract surgery. OBJECTIVES: The objective of this review was to evaluate the effectiveness and safety of surgery for post-vitrectomy cataract with respect to visual acuity, quality of life, and other outcomes. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 4), Ovid MEDLINE, Ovid MEDLINE in-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily Update, Ovid OLDMEDLINE (January 1946 to May 2013), EMBASE (January 1980 to May 2013, Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to May 2013), PubMed (January 1946 to May 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 22 May 2013. SELECTION CRITERIA: We planned to include randomized and quasi-randomized controlled trials comparing cataract surgery with no surgery in adult patients who developed cataract following vitrectomy. DATA COLLECTION AND ANALYSIS: Two authors screened the search results independently according to the standard methodological procedures expected by The Cochrane Collaboration. MAIN RESULTS: We found no randomized or quasi-randomized controlled trials comparing cataract surgery with no cataract surgery for patients who developed cataracts following vitrectomy surgery. AUTHORS\u27 CONCLUSIONS: There is no evidence from randomized or quasi-randomized controlled trials on which to base clinical recommendations for surgery for post-vitrectomy cataract. There is a clear need for randomized controlled trials to address this evidence gap. Such trials should stratify participants by their age, the retinal disorder leading to vitrectomy, and the status of the underlying disease process in the contralateral eye. Outcomes assessed in such trials may include gain of vision on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale, quality of life, and adverse events such as posterior capsular rupture. Both short-term (six-month) and long-term (one-year or two-year) outcomes should be examined

A deep learning enabler for non-intrusive reduced order modeling of fluid flows

In this paper, we introduce a modular deep neural network (DNN) framework for data-driven reduced order modeling of dynamical systems relevant to fluid flows. We propose various deep neural network architectures which numerically predict evolution of dynamical systems by learning from either using discrete state or slope information of the system. Our approach has been demonstrated using both residual formula and backward difference scheme formulas. However, it can be easily generalized into many different numerical schemes as well. We give a demonstration of our framework for three examples: (i) Kraichnan-Orszag system, an illustrative coupled nonlinear ordinary differential equations, (ii) Lorenz system exhibiting chaotic behavior, and (iii) a non-intrusive model order reduction framework for the two-dimensional Boussinesq equations with a differentially heated cavity flow setup at various Rayleigh numbers. Using only snapshots of state variables at discrete time instances, our data-driven approach can be considered truly non-intrusive, since any prior information about the underlying governing equations is not required for generating the reduced order model. Our \textit{a posteriori} analysis shows that the proposed data-driven approach is remarkably accurate, and can be used as a robust predictive tool for non-intrusive model order reduction of complex fluid flows.Comment: 36 pages, 21 figure

Cross-Dataset Adaptation for Instrument Classification in Cataract Surgery Videos

Surgical tool presence detection is an important part of the intra-operative and post-operative analysis of a surgery. State-of-the-art models, which perform this task well on a particular dataset, however, perform poorly when tested on another dataset. This occurs due to a significant domain shift between the datasets resulting from the use of different tools, sensors, data resolution etc. In this paper, we highlight this domain shift in the commonly performed cataract surgery and propose a novel end-to-end Unsupervised Domain Adaptation (UDA) method called the Barlow Adaptor that addresses the problem of distribution shift without requiring any labels from another domain. In addition, we introduce a novel loss called the Barlow Feature Alignment Loss (BFAL) which aligns features across different domains while reducing redundancy and the need for higher batch sizes, thus improving cross-dataset performance. The use of BFAL is a novel approach to address the challenge of domain shift in cataract surgery data. Extensive experiments are conducted on two cataract surgery datasets and it is shown that the proposed method outperforms the state-of-the-art UDA methods by 6%. The code can be found at https://github.com/JayParanjape/Barlow-AdaptorComment: MICCAI 202

GLSFormer: Gated - Long, Short Sequence Transformer for Step Recognition in Surgical Videos

Automated surgical step recognition is an important task that can significantly improve patient safety and decision-making during surgeries. Existing state-of-the-art methods for surgical step recognition either rely on separate, multi-stage modeling of spatial and temporal information or operate on short-range temporal resolution when learned jointly. However, the benefits of joint modeling of spatio-temporal features and long-range information are not taken in account. In this paper, we propose a vision transformer-based approach to jointly learn spatio-temporal features directly from sequence of frame-level patches. Our method incorporates a gated-temporal attention mechanism that intelligently combines short-term and long-term spatio-temporal feature representations. We extensively evaluate our approach on two cataract surgery video datasets, namely Cataract-101 and D99, and demonstrate superior performance compared to various state-of-the-art methods. These results validate the suitability of our proposed approach for automated surgical step recognition. Our code is released at: https://github.com/nisargshah1999/GLSFormerComment: Accepted to MICCAI 2023 (Early Accept

Statistics of pressure and of pressure-velocity correlations in isotropic turbulence

Some pressure and pressure-velocity correlation in a direct numerical simulations of a three-dimensional turbulent flow at moderate Reynolds numbers have been analyzed. We have identified a set of pressure-velocity correlations which posseses a good scaling behaviour. Such a class of pressure-velocity correlations are determined by looking at the energy-balance across any sub-volume of the flow. According to our analysis, pressure scaling is determined by the dimensional assumption that pressure behaves as a ``velocity squared'', unless finite-Reynolds effects are overwhelming. The SO(3) decompositions of pressure structure functions has also been applied in order to investigate anisotropic effects on the pressure scaling.Comment: 21 pages, 8 figur

Comparison of pattern of self-medication among urban and rural population of Telangana state, India

Background: Self-medication is one of the components of self-care, which may treat the disease or result in worsening of the condition due to irrational use of drug.1 In developing countries like India, self-medication is a common practice as it provides a low-cost alternative for people who cannot afford the high cost of clinical service, and is time efficient.Methods: A total of 110 participants completed the study. A printed questionnaire was given to those who were willing to participate in the study and came to buy medicines without consulting a doctor to various pharmacy outlets.Results: Among the group of drugs used antibiotics were the common drugs used in rural area (74%) and cough suppressants (50%) in urban area. Symptoms for opting self-medication were fever and common cold in both the groups. Individuals in both areas took self-medication based on their previous prescriptions (rural 42% vs urban41.6%) and advertisements. Rural individuals preferred self-medication with the opinion of saving time and urban people felt that it was less expensive.Conclusions: There is a difference in the pattern self-medication among rural and urban individuals. It is also to be noted that use of antibiotics may result in problems related to drug resistance. So, it would be advisable to restrict the sale of antibiotics as over the counter drugs