713 research outputs found

    Common fixed point theorems for occasionally converse commuting mappings in symmetric spaces

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    In this paper, we introduce the notion of occasionally converse commuting (occ) mappings. Every converse commuting mappings ([1]) are (occ) but the converse need not be true (see, Ex.1.1-1.3). By using this concept, we prove two common fixed point results for a quadruple of self-mappings which satisfy an implicit relation. In first result one pair is (owc) [5] and the other is (occ), while in second result both the pairs are (occ). We illustrate our theorems by suitable examples. Since, there may exist mappings which are (occ) but not conversely commuting, the Theorems 1.1[2], 1.2[2] and 1.3[3] fails to handle those mapping pairs which are only (occ) but not conversely commuting (like Ex.1.4). On the other hand, since every conversely commuting mappings are (occ), so our Theorem 3.1 and 3.2 generalizes these theorems and the main results of Pathak and Verma [6]-[7] &nbsp

    Network model of immune responses reveals key effectors to single and co-infection dynamics by a respiratory bacterium and a gastrointestinal helminth

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    Co-infections alter the host immune response but how the systemic and local processes at the site of infection interact is still unclear. The majority of studies on co-infections concentrate on one of the infecting species, an immune function or group of cells and often focus on the initial phase of the infection. Here, we used a combination of experiments and mathematical modelling to investigate the network of immune responses against single and co-infections with the respiratory bacterium Bordetella bronchiseptica and the gastrointestinal helminth Trichostrongylus retortaeformis. Our goal was to identify representative mediators and functions that could capture the essence of the host immune response as a whole, and to assess how their relative contribution dynamically changed over time and between single and co-infected individuals. Network-based discrete dynamic models of single infections were built using current knowledge of bacterial and helminth immunology; the two single infection models were combined into a co-infection model that was then verified by our empirical findings. Simulations showed that a T helper cell mediated antibody and neutrophil response led to phagocytosis and clearance of B. bronchiseptica from the lungs. This was consistent in single and co-infection with no significant delay induced by the helminth. In contrast, T. retortaeformis intensity decreased faster when co-infected with the bacterium. Simulations suggested that the robust recruitment of neutrophils in the co-infection, added to the activation of IgG and eosinophil driven reduction of larvae, which also played an important role in single infection, contributed to this fast clearance. Perturbation analysis of the models, through the knockout of individual nodes (immune cells), identified the cells critical to parasite persistence and clearance both in single and co-infections. Our integrated approach captured the within-host immuno-dynamics of bacteria-helminth infection and identified key components that can be crucial for explaining individual variability between single and co-infections in natural populations

    Exercise Responses to Metabolic Function on High Altitude Pulmonary Edema Susceptible Individuals

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    The study was aimed to evaluate and compare resting and exercise induced metabolic responses between acclimatized high altitude pulmonary edema (HAPE) susceptible (HAPE-s) and HAPE resistance (HAPE-r) volunteers at sea level. A group of 14 Indian soldiers volunteered for this study, divided into two groups, (i) HAPE-s, with past history of HAPE [n1 = 7; age = 33.3 ± 4.5 (M ± SD)] and (ii) HAPE-r, with prior history of repeated exposure to high altitude and without suffering HAPE [n2 = 7; age = 31.9 ± 4.2 (M ± SD)]. Respiratory frequency (fR), tidal volume (T), minute ventilation (E), oxygen consumption (O2), carbon dioxide output (CO2), heart rate (HR) and respiratory quotient (RQ) were recorded on all the volunteers during resting and exercise conditions. Ventilatory equivalent for oxygen (EqO2) and oxygen pulse (O2P) were calculated. Significant differences were observed between HAPE-s and HAPE-r volunteers in fRrest (25.3% higher), O2Prest (23.7% lower), Emax (50.9% lower) (all P<0.05), fRmax (55.7% lower), O2max (55.5% lower), O2Pmax (34.2% lower) (all P<0.01) and CO2max (42.1% lower, P<0.001). Rest of the parameters did not show any significant differences between the study groups. The study revealed that resting and exercise induced metabolic responses of HAPE-r volunteers was better as compared to acclimatized HAPE-s volunteers at sea level

    Social entrepreneurs in challenging places: A Delphi study of experiences and perspectives

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    Social Enterprises have grown in number and scope in response to reductions in state-provided welfare and increasing ambition to improve social conditions. While a range of issues have been identified in the literature as affecting the ability of Social Enterprises to successfully conduct their activities, there is currently a dearth of research into the relative influence of these factors. This study explores and ranks the challenges faced by social entrepreneurs in South Wales. Based on a Delphi study with 21 social entrepreneurs, government policy-developers and scholars, it presents a hierarchy of 14 factors, useful instruments for informing social entrepreneurs and policy-makers about the way social enterprises are managed, and how national and local policy should be developed. As part of this, the study also identifies four novel factors that affect the sustainability of social enterprises: ‘Professionalisation of Marketing’, ‘Perception of Validity’, ‘Leadership’ and ‘Situatedness’

    Summertime PM₂.₅ ionic species in four major cities of China : nitrate formation in an ammonia-deficient atmosphere

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    2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Efficient control of atmospheric sulfate production based on three formation regimes

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    The formation of sulfate (SO₄²⁻) in the atmosphere is linked chemically to its direct precursor, sulfur dioxide (SO₂), through several key oxidation paths for which nitrogen oxides or NO_x (NO and NO₂) play essential roles. Here we present a coherent description of the dependence of SO₄²⁻ formation on SO₂ and NO_x under haze-fog conditions, in which fog events are accompanied by high aerosol loadings and fog-water pH in the range of 4.7–6.9. Three SO₄²⁻ formation regimes emerge as defined by the role played by NO_x. In the low-NO_x regime, NO_x act as catalyst for HO_x, which is a major oxidant for SO₂, whereas in the high-NO_x regime, NO₂ is a sink for HO_x. Moreover, at highly elevated NO_x levels, a so-called NO₂-oxidant regime exists in which aqueous NO₂ serves as the dominant oxidant of SO₂. This regime also exists under clean fog conditions but is less prominent. Sensitivity calculations using an emission-driven box model show that the reduction of SO₄²⁻ is comparably sensitive to the reduction of SO₂ and NO_x emissions in the NO₂-oxidant regime, suggesting a co-reduction strategy. Formation of SO₄²⁻ is relatively insensitive to NO_x reduction in the low-NO_x regime, whereas reduction of NO_x actually leads to increased SO₄²⁻ production in the intermediate high-NO_x regime

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Climatic risks and impacts in South Asia: extremes of water scarcity and excess

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    This paper reviews the current knowledge of climatic risks and impacts in South Asia associated with anthropogenic warming levels of 1.5°C to 4°C above pre-industrial values in the 21st century. It is based on the World Bank Report “Turn Down the Heat, Climate Extremes, Regional Impacts and the Case for Resilience” (2013). Many of the climate change impacts in the region, which appear quite severe even with relatively modest warming of 1.5–2°C, pose significant hazards to development. For example, increased monsoon variability and loss or glacial meltwater will likely confront populations with ongoing and multiple challenges. The result is a significant risk to stable and reliable water resources for the region, with increases in peak flows potentially causing floods and dry season flow reductions threatening agriculture. Irrespective of the anticipated economic development and growth, climate projections indicate that large parts of South Asia’s growing population and especially the poor are likely to remain highly vulnerable to climate change

    2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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