64 research outputs found

    GIFT: Gesture-Based Interaction by Fingers Tracking, an Interaction Technique for Virtual Environment

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    Three Dimensional (3D) interaction is the plausible human interaction inside a Virtual Environment (VE). The rise of the Virtual Reality (VR) applications in various domains demands for a feasible 3D interface. Ensuring immersivity in a virtual space, this paper presents an interaction technique where manipulation is performed by the perceptive gestures of the two dominant fingers; thumb and index. The two fingertip-thimbles made of paper are used to trace states and positions of the fingers by an ordinary camera. Based on the positions of the fingers, the basic interaction tasks; selection, scaling, rotation, translation and navigation are performed by intuitive gestures of the fingers. Without keeping a gestural database, the features-free detection of the fingers guarantees speedier interactions. Moreover, the system is user-independent and depends neither on the size nor on the color of the users’ hand. With a case-study project; Interactions by the Gestures of Fingers (IGF) the technique is implemented for evaluation. The IGF application traces gestures of the fingers using the libraries of OpenCV at the back-end. At the front-end, the objects of the VE are rendered accordingly using the Open Graphics Library; OpenGL. The system is assessed in a moderate lighting condition by a group of 15 users. Furthermore, usability of the technique is investigated in games. Outcomes of the evaluations revealed that the approach is suitable for VR applications both in terms of cost and accuracy

    EVEN-VE: Eyes Visibility Based Egocentric Navigation for Virtual Environments

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    Navigation is one of the 3D interactions often needed to interact with a synthetic world. The latest advancements in image processing have made possible gesture based interaction with a virtual world. However, the speed with which a 3D virtual world responds to a user’s gesture is far greater than posing of the gesture itself. To incorporate faster and natural postures in the realm of Virtual Environment (VE), this paper presents a novel eyes-based interaction technique for navigation and panning. Dynamic wavering and positioning of eyes are deemed as interaction instructions by the system. The opening of eyes preceded by closing for a distinct time-threshold, activates forward or backward navigation. Supporting 2-Degree of Freedom head’s gestures (Rolling and Pitching) panning is performed over the xy-plane. The proposed technique was implemented in a case-study project; EWI (Eyes Wavering based Interaction). With EWI, real time detection and tracking of eyes are performed by the libraries of OpenCV at the backend. To interactively follow trajectory of both the eyes, dynamic mapping is performed in OpenGL. The technique was evaluated in two separate sessions by a total of 28 users to assess accuracy, speed and suitability of the system in Virtual Reality (VR). Using an ordinary camera, an average accuracy of 91% was achieved. However, assessment made by using a high quality camera testified that accuracy of the system could be raised to a higher level besides increase in navigation speed. Results of the unbiased statistical evaluations suggest/demonstrate applicability of the system in the emerging domains of virtual and augmented realities

    Two Hand Gesture Based 3D Navigation in Virtual Environments

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    Natural interaction is gaining popularity due to its simple, attractive, and realistic nature, which realizes direct Human Computer Interaction (HCI). In this paper, we presented a novel two hand gesture based interaction technique for 3 dimensional (3D) navigation in Virtual Environments (VEs). The system used computer vision techniques for the detection of hand gestures (colored thumbs) from real scene and performed different navigation (forward, backward, up, down, left, and right) tasks in the VE. The proposed technique also allow users to efficiently control speed during navigation. The proposed technique is implemented via a VE for experimental purposes. Forty (40) participants performed the experimental study. Experiments revealed that the proposed technique is feasible, easy to learn and use, having less cognitive load on users. Finally gesture recognition engines were used to assess the accuracy and performance of the proposed gestures. kNN achieved high accuracy rates (95.7%) as compared to SVM (95.3%). kNN also has high performance rates in terms of training time (3.16 secs) and prediction speed (6600 obs/sec) as compared to SVM with 6.40 secs and 2900 obs/sec

    Altered cyclooxygenase-1 and enhanced thromboxane receptor activities underlie attenuated endothelial dilatory capacity of omental arteries in obesity

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    AIMS: Obesity is a risk factor for endothelial dysfunction, the severity of which is likely to vary depending on extent and impact of adiposity on the vasculature. This study investigates the roles of cyclooxygenase isoforms and thromboxane receptor activities in the differential endothelial dilatory capacities of arteries derived from omental and subcutaneous adipose tissues in obesity. MAIN METHODS: Small arteries were isolated from omental and subcutaneous adipose tissues obtained from consented morbidly obese patients (n = 65, BMI 45 ± 6 kg m-2 [Mean ± SD]) undergoing bariatric surgery. Relaxation to acetylcholine was studied by wire myography in the absence or presence of indomethacin (10 μM, cyclooxygenase inhibitor), FR122047 (1 μM, cyclooxygenase-1 inhibitor), Celecoxib (4 μM, cyclooxygenase-2 inhibitor), Nω-Nitro-L-arginine methyl ester (L-NAME, 100 μM, nitric oxide synthase inhibitor) or combination of apamin (0.5 μM) and charybdotoxin (0.1 μM) that together inhibit endothelium-derived hyperpolarizing factor (EDHF). Contractions to U46619 (thromboxane A2 mimetic) were also studied. KEY FINDINGS: Acetylcholine relaxation was significantly attenuated in omental compared with subcutaneous arteries from same patients (p < 0.01). Indomethacin (p < 0.01) and FR122047 (p < 0.001) but not Celecoxib significantly improved the omental arteriolar relaxation. Cyclooxygenase-1 mRNA and U46619 contractions were both increased in omental compared with subcutaneous arteries (p < 0.05). L-NAME comparably inhibited acetylcholine relaxation in both arteries, while apamin+charybdotoxin were less effective in omental compared with subcutaneous arteries. SIGNIFICANCE: The results show that the depot-specific reduction in endothelial dilatory capacity of omental compared with subcutaneous arteries in obesity is in large part due to altered cyclooxygenase-1 and enhanced thromboxane receptor activities, which cause EDHF deficiency

    COVID-19 Vaccine Hesitancy among Pregnant Women Attending Antenatal Clinics in Pakistan: A Multicentric, Prospective, Survey-Based Study

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    This study aimed to assess the vaccination status and factors contributing to vaccine hesitancy among pregnant women in the largest province of Pakistan. A multicentric, prospective, survey-based study using an interviewer-administered tool was conducted among pregnant women attending antenatal clinics between 1 December 2021 through 30 January 2022 across seven hospitals in Pakistan. The healthcare professionals providing care at the participating hospitals administered the survey. Four hundred and five pregnant women fully consented and completed the study. The majority of the study participants (70.6%, n = 286) were aged between 25 and 34 and had a previous successful pregnancy history. More than half of the study participants (56.0%, n = 227) did not receive COVID-19 vaccination at the time of data collection despite their family members (93.9%, n = 372) had already received at least one dose of COVID-19 vaccine. Among those who received COVID-19 vaccination (n = 173), vaccine efficacy, protection for the foetus, and risk of COVID-19-associated hospitalisation were the main driving factors for vaccine hesitancy. The majority of the unvaccinated women (77.8%, n = 182) had no intention of receiving the vaccine. However, more than two-thirds (85.7%, n = 342) consulted the doctor about COVID-19 vaccines, and most were recommended to receive COVID-19 vaccines by the doctors (80.7%, n = 280). Women were significantly more likely to be vaccinated if they had employment (odds ratio [OR] 4.47, 95% confidence interval [CI]: 2.31–8.64) compared with their counterparts who were homemakers, consulted their doctors (OR 0.12, 95% CI: 0.04–0.35), and if they did not have pregnancy-related issues (OR 6.02, 95% CI: 2.36–15.33). In this study, vaccine hesitancy was prevalent, and vaccine uptake was low among pregnant women. Education and employment did impact COVID vaccination uptake, emphasising the need for more targeted efforts to enhance the trust in vaccines

    RIGHT PURE UNI-SOFT IDEALS OF ORDERED SEMIGROUPS

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    In this paper, we initiate the study of pure uni-soft ideals in ordered semigroups. The soft version of right pure ideals in ordered semigroups is considered which is an extension of the concept of right pure ideal in ordered semigroups. We also give the main result for right pure uni-soft ideals in ordered semigroups and characterize right weakly regular ordered semigroups in terms of right pure uni-soft ideals

    Detecting Discontinuities Over Triangular Meshes Using Multiwavelets

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    It is well known that solutions to nonlinear hyperbolic PDEs develop discontinuities in time. The generation of spurious oscillations in such regions can be prevented by applying a limiter in the troubled zones. In earlier work, we constructed a multiwavelet troubled-cell indicator for one and (tensor-product) two dimensions (SIAM J. Sci. Comput. 38(1):A84–A104, 2016). In this paper, we investigate multiwavelet troubled-cell indicators on structured triangular meshes. One indicator uses a problem-dependent parameter; the other indicator is combined with outlier detection

    Downregulation of CYP17A1 by 20-hydroxyecdysone: plasma progesterone and its vasodilatory properties

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    Aim: To investigate the effect of 20-hydroxyecdysone on steroidogenic pathway genes and plasma progesterone, and its potential impact on vascular functions. Methods: Chimeric mice with humanized liver were treated with 20-hydroxyecdysone for 3 days, and hepatic steroidogenic pathway genes and plasma progesterone were measured by transcriptomics and GC–MS/MS, respectively. Direct effects on muscle and mesenteric arterioles were assessed by myography. Results: CYP17A1 was downregulated in 20-hydroxyecdysone-treated mice compared with untreated group (p = 0.04), with an insignificant increase in plasma progesterone. Progesterone caused vasorelaxation which was blocked by 60 mM KCl, but unaffected by nitric oxide synthase inhibition. Conclusion: In the short term, 20-hydroxyecdysone mediates CYP17A1 downregulation without a significant increase in plasma progesterone, which has a vasodilatory effect involving inhibition of voltage-dependent calcium channels, and the potential to enhance 20-hydroxyecdysone vasorelaxation
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