Testing vertex connectivity of bowtie 1-plane graphs

A separating set of a connected graph $G$ is a set of vertices $S$ such that $G-S$ is disconnected. $S$ is a minimum separating set of $G$ if there is no separating set of $G$ with fewer vertices than $S$. The size of a minimum separating set of $G$ is called the vertex connectivity of $G$. A separating set of $G$ that is a cycle is called a separating cycle of $G$. Let $G$ be a planar graph with a given planar embedding. Let $\Lambda(G)$ be a supergraph of $G$ obtained by inserting a face vertex in each face of $G$ and connecting the face vertex to all vertices on the boundary of the face. It is well known that a set $S$ is a minimum separating set of a planar graph $G$ if and only if the vertices of $S$ can be connected together using face vertices to get a cycle $X$ of length $2|S|$ that is separating in $\Lambda(G)$. We extend this correspondence between separating sets and separating cycles from planar graphs to the class of bowtie 1-plane graphs. These are graphs that are embedded on the plane such that each edge is crossed at most once by another edge, and the endpoints of each such crossing induce either $K_4$, $K_4 \setminus \{e\}$ or $C_4$. Using this result, we give an algorithm to compute the vertex connectivity of a bowtie 1-plane graph in linear time

Three essays in sustainable operations management with implications for the triple bottom line

We are in a state of overshoot; the human population today consumes natural resources at a rate that exceeds what the planet can sustainably provide in the long term (Meadows et al., 2004). Two key causes of this overshoot are the overconsumption of natural resources, and the reluctance or inability of society to remedy this overconsumption through the appropriate use and deployment of technology and management practices. In this light, the work contained in this dissertation is intended to explore potential solutions that operations management can provide to mitigate the impact of these two causes of overshoot. Therefore, in the spirit of the Triple Bottom Line (3BL) framework for sustainability, we evaluate environmental and social, along with the economic implications of strategic and operational decisions in the contexts of natural resource management and green product development in this dissertation. Freshwater is an invaluable resource to all life on earth. Groundwater reservoirs, an important source of freshwater, are drying up across the United States and the globe, creating a severe mismatch in the supply and demand of freshwater. Two new management paradigms have cropped up in recent years to remedy this mismatch: water trading and privatization. The first essay in this dissertation explores the impact of these paradigms on groundwater management and the ensuing 3BL implications. Voluntary green product development has emerged as a viable alternative to the traditional 'command and control' approach for environmental regulation. The second essay in this chapter addresses a producer's problem of labeling its product to communicate its environmental attributes that are otherwise invisible to consumers. The key objectives of this essay are to identify the efficacy of external ecolabeling agencies and the role of producer credibility in stimulating green product development and its resulting benefits from a 3BL perspective. The final essay in this dissertation explores the phenomenon of pre-competitive collaboration between firms in the context of green product development. In it, we identify the motivation for and the 3BL implications of horizontal R&D collaboration between competing supply chains as well as vertical collaboration within a supply chain through cost-sharing

Experimental Implementation of Model Predictive Control Scheme for Control of Semi-active Suspension System

International audienc

Single Axis Semi Automatic Drilling Machine with PLC Control

ABSTRACT:Under conventionally controlled drilling machine the depth controlled cannot be made possible. Due to over drilling the job gets failed. While drilling we cannot measure the drilling depth during drilling process. Hence the semiautomatic drilling machine will automatically control the depth of the job and it of safer mode. In some cases due to over drilling the work bench will gets destroyed or the tool will be damaged. Hence for these conditions our project work had been taken up to get through the new technologies. This made the drilling machine easier. This semiautomatic drilling machine is very well used in mechanical workshops and it made the work easier. It consumes less time and the finishing process will be quite easier, while compared to the conventional drilling machine

Spatial Variations in Vitreous Oxygen Consumption

We investigated the spatial variation of vitreous oxygen consumption in enucleated porcine eyes. A custom made oxygen source was fabricated that could be localized to either the mid or posterior vitreous cavity and steady state vitreous oxygen tension was measured as a function of distance from the source using a commercially available probe. The reaction rate constant of ascorbate oxidation was estimated ex vivo by measuring the change in oxygen tension over time using vitreous harvested from porcine eyes. Vitreous ascorbate from mid and posterior vitreous was measured spectrophotometrically. When the oxygen source was placed in either the mid-vitreous (N = 6) or the posterior vitreous (N = 6), we measured a statistically significant decrease in vitreous oxygen tension as a function of distance from the oxygen source when compared to control experiments without an oxygen source; (p<0.005 for mid-vitreous and p<0.018 for posterior vitreous at all distances). The mid-vitreous oxygen tension change was significantly different from the posterior vitreous oxygen tension change at 2 and 3mm distances from the respective oxygen source (p<0.001). We also found a statistically significant lower concentration of ascorbate in the mid-vitreous as compared to posterior vitreous (p = 0.02). We determined the reaction rate constant, k = 1.61 M^(-1)s^(-1) ± 0.708 M^(-1)s^(-1) (SE), of the oxidation of ascorbate which was modeled following a second order rate equation. Our data demonstrates that vitreous oxygen consumption is higher in the posterior vitreous compared to the mid-vitreous. We also show spatial variations in vitreous ascorbate concentration

Imaging spectrum of extrapulmonary manifestations of COVID-19 infection- a multi-centre descriptive study from Southern India

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is the causative agent for coronavirus disease 2019 (COVID-19) pandemic. While the primary organ of involvement in this disease is the lung, multiple other organ systems can be involved either due to direct viral cytopathic effects or due to thrombo-inflammation and immune system dysregulation. In this study we describe the spectrum of extrapulmonary imaging findings encountered in our patients with COVID-19.Methods: This was a retrospective observational study conducted in three tertiary care hospitals in the city of Chennai in southern India. All cross-sectional imaging studies (other than lung imaging studies) performed in patients who had proven COVID-19 infection by RT-PCR testing during the period from April 2020 to March 2021 were included as part of the study. Extrapulmonary findings in these imaging studies were recorded and collated system-wise.Results: A total of 96 non-lung imaging studies were performed in patients who had RT-PCR positivity for COVID-19 infection. Among these a total of 30 studies had extrapulmonary imaging findings. Vascular involvement was seen in 14 patients, central nervous system involvement in 13 patients, abdomen involvement in 2 patients, and cardiac involvement in 1 patient. Vascular manifestations included arterial and venous thrombosis. Neurological manifestations included stroke, encephalitis and demyelination. Abdominal manifestations included enteritis and acute kidney injury. Cardiac manifestation was in form of myocarditis.Conclusions: Extrapulmonary imaging findings in COVID-19 are uncommon but not rare. Multisystem thrombotic manifestations and central nervous system involvement account for majority of extrapulmonary imaging findings in COVID-19

Quality of Occupational Therapy Research in India - A Descriptive Review

Background: Occupational therapy (OT) enhances functional independence in the daily activities of people with disabilities and subsequently their quality of life. Research in OT generates evidence to provide safe and effective services to the disabled. However, OT research in India has been shown to have various methodological limitations. These methodological limitations are expected to impact the quality of OT research as well as the evidence derived from this research to inform decision‑making in rehabilitation. The majority of the OT research is disseminated and promoted through the All India Occupational Therapists’ Association’s (AIOTA) annual national conference (ANC). Analyzing the abstracts, selected for the presentation at the ANC could help understand and strategically improve the quality of OT research in India. Objectives: To explore and describe the quality of OT research in India. Study Design: Descriptive analysis. Methods: Descriptive, nonsystematic review and analysis of the key methodological aspects of the conference abstracts submitted for the AIOTA ANC published in the Indian Journal of OT (IJOT) from 2017 to 2021 was carried out. Information related to the methodological aspects of the research abstracts was extracted using a data extraction form and the data were synthesized and reported descriptively. Results: About 218 abstracts had been selected for either poster or oral presentations in the AIOTA ANC. All the abstracts were included for the review. A total of 8055 participants were recruited for the studies conducted from 2017 to 2021. About 5757 (72) of the participants were recruited for cross‑sectional studies. Nearly 72 (33) of the abstracts presented were related to cross‑sectional studies, 52 (24) were case studies and 66 (30) were experimental studies. However, research designs implying highest level of evidence such as systematic reviews were only 4 (2) and randomized controlled trials were only 9 (4) with 297 participants. Notably, 203 (98) of the all the studies evaluating effectiveness of interventions or aiming to investigate associations reported positive results with statistically significant improvements and associations. Conclusion: The review provides invaluable information relatedto the quality of OT research in India. It implies the need to improve the scientific rigor of the evidence generated in relation to OT research in India. This review also implies the need for a radical change and strengthening of OT research within OT education and professional practice in India. National and global OT associations need to prioritize good quality OT research by enhancing the research skills and competencies of OTs in India. This could help promote evidence‑based OT science and develop the OT profession in the world’s second‑most populous country. In addition, it is also expected to encourage those OT researchers who have been striving to build OT research standards in India

Wireless Oxygen Generator to Treat Retinal Ischemia

Purpose : It is well known that retinal hypoxia plays an important role in the diabetic retinopathy (DR) pathophysiology. Current treatments of DR are focused on reducing retinal oxygen demand and controlling angiogenesis through intravitreal injections. Previous publications suggest that supplementing intravitreal oxygen might improve outcomes for retinal ischemia. A microelectronic and bio micro-electro-mechanical system oxygenator implant has been designed to transport oxygen from the sub-conjunctival space to the proximity of the inner retina. The main objective of this study is to determine safety, efficacy and therapeutic levels of vitreous cavity oxygenation needed to support the retina by electrolysis-based oxygen generation implant. Methods : The study was performed with local IACUC approval and in accordance with the ARVO guidelines on animal use. Three eyes of healthy pigmented rabbits (2-3kgs) were included in the study. With the animal anesthetized, the oxygenator was implanted and affixed onto the sclera. Electrolysis and intraocular measurements of partial pressure of oxygen (pO_2) were performed prior to suturing the conjunctiva back to the limbus. An oxygen probe (Oxford Optronix, London, UK) was placed intravitreal via pars plana and positioned next to the diffuser without touching adjacent structures. Baseline pO2 measurements were recorded with the device off and no electrolysis. The device was then turned on for at least 3 minutes and electrolysis was confirmed by direct visualization of bubbles. Continuous measurement of pO_2 levels next to the device were performed during electrolysis. The relationship between electrolysis and pO_2 was analyzed. Results : Oxygenator devices were successfully implanted. Intraocular pO_2 levels increased progressively to 79.1mmHg +5.52mmHg, 121.7mmHg +8.91mmHg and over 200mmHg after 2, 5 and 15 minutes of electrolysis, respectively (see Figure 1). Oxygen levels decreased exponentially as the probe was moved away from the device as predicted by computational models thereby minimizing oxygen toxicity to surrounding tissues. The Oxygenator implantation procedure was followed up for 7 days without presence of ocular complications. Conclusions : Our study demonstrates that intraocular oxygen levels can be elevated following implantation and activation of the oxygenator device. Further experiments will be conducted in a long-term period

Wireless Oxygen Generator to Treat Retinal Ischemia

Purpose : It is well known that retinal hypoxia plays an important role in the diabetic retinopathy (DR) pathophysiology. Current treatments of DR are focused on reducing retinal oxygen demand and controlling angiogenesis through intravitreal injections. Previous publications suggest that supplementing intravitreal oxygen might improve outcomes for retinal ischemia. A microelectronic and bio micro-electro-mechanical system oxygenator implant has been designed to transport oxygen from the sub-conjunctival space to the proximity of the inner retina. The main objective of this study is to determine safety, efficacy and therapeutic levels of vitreous cavity oxygenation needed to support the retina by electrolysis-based oxygen generation implant. Methods : The study was performed with local IACUC approval and in accordance with the ARVO guidelines on animal use. Three eyes of healthy pigmented rabbits (2-3kgs) were included in the study. With the animal anesthetized, the oxygenator was implanted and affixed onto the sclera. Electrolysis and intraocular measurements of partial pressure of oxygen (pO_2) were performed prior to suturing the conjunctiva back to the limbus. An oxygen probe (Oxford Optronix, London, UK) was placed intravitreal via pars plana and positioned next to the diffuser without touching adjacent structures. Baseline pO2 measurements were recorded with the device off and no electrolysis. The device was then turned on for at least 3 minutes and electrolysis was confirmed by direct visualization of bubbles. Continuous measurement of pO_2 levels next to the device were performed during electrolysis. The relationship between electrolysis and pO_2 was analyzed. Results : Oxygenator devices were successfully implanted. Intraocular pO_2 levels increased progressively to 79.1mmHg +5.52mmHg, 121.7mmHg +8.91mmHg and over 200mmHg after 2, 5 and 15 minutes of electrolysis, respectively (see Figure 1). Oxygen levels decreased exponentially as the probe was moved away from the device as predicted by computational models thereby minimizing oxygen toxicity to surrounding tissues. The Oxygenator implantation procedure was followed up for 7 days without presence of ocular complications. Conclusions : Our study demonstrates that intraocular oxygen levels can be elevated following implantation and activation of the oxygenator device. Further experiments will be conducted in a long-term period