40 research outputs found

    ON THE NORM OF JORDAN ELEMENTARY OPERATOR IN TENSOR PRODUCT OF C*-ALGEBRAS

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    The norm property of different types of Elementary operators has attracted a lot of researchers due to its wide range applications in functional analysis. From available literature the norm of Jordan elementary operator has been determined in C*-algebras, JB*-algebras,standard operator algebra and prime JB*-triple but not much has been done in tensor product of C*-algebras. This paper, dealt with the norm of Jordan elementary operator in a tensor product of C*-algebras. More precisely, the paper investigated the bounds of the norm of Jordan elementary operator in a tensor product of C*-algebras and obtained that The concept of finite rank operator and properties of tensor product of Hilbert spaces and operators and vectors in Hilbert spaces were used to achieve the paper’s objective

    Factors influencing the utilization of family planning services among HIV infected women in a Kenyan health facility

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    Background: Women’s knowledge and access to reproductive health services improves their ability to safely achieve their required fertility and reduces maternal and infant morbidity and mortality. We aimed to determine the utilization of family planning (FP) among HIV Infected women visiting the HIV clinic.Methods: A cross-sectional mixed quantitative and qualitative study among HIV positive females in Nairobi, Kenya was conducted. Consenting women completed a questionnaire that assessed the utilization of FP services. Descriptive and inferential analysis was carried out on quantitative data to determine significant associations with FP utilization. Qualitative data were analyzed after coding for significant clauses and transcribing to determine themes arising.Results: We enrolled a total of 387 patients, mean age (IQ range) 40 years (36-44). The contraceptive prevalence was 53% with an unmet need of family planning of 38.5%. Patients were more likely to use family planning if they were married, if condoms were offered at the clinic, if they discussed contraception with the clinic staff and their partners. They were less likely to use FP if they had expressed fertility desire. Widows were less likely to use any form of FP than married couples despite having sexual partners. The main themes on the barriers of utilization of family planning services included lack of knowledge, pill burden, and adverse reactions to hormonal FP.Conclusions: The unmet need of family planning is high, and heightened measures need to be taken to improve the utilization of the service. Particular groups such as sexually active widows and single women should be targeted for these interventions

    Molecular basis for heat desensitization of TRPV1 ion channels.

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    The transient receptor potential vanilloid 1 (TRPV1) ion channel is a prototypical molecular sensor for noxious heat in mammals. Its role in sustained heat response remains poorly understood, because rapid heat-induced desensitization (Dh) follows tightly heat-induced activation (Ah). To understand the physiological role and structural basis of Dh, we carried out a comparative study of TRPV1 channels in mouse (mV1) and those in platypus (pV1), which naturally lacks Dh. Here we show that a temperature-sensitive interaction between the N- and C-terminal domains of mV1 but not pV1 drives a conformational rearrangement in the pore leading to Dh. We further show that knock-in mice expressing pV1 sensed heat normally but suffered scald damages in a hot environment. Our findings suggest that Dh evolved late during evolution as a protective mechanism and a delicate balance between Ah and Dh is crucial for mammals to sense and respond to noxious heat

    Antiretroviral therapy outcomes among adolescents and young adults in a Tertiary hospital in Kenya

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    Background: Limited data is available on the treatment outcomes of HIV infected adolescents and young adults (AYA) in sub-Saharan Africa. HIV-infected adolescents and young adults (AYA) are at high risk of developing antiretroviral treatment failure. Objective: To determine the clinical, immunological and virologic outcomes of AYA at a tertiary hospital in Kenya. Methodology: A longitudinal study was conducted among AYA age 10-24 years attending Kenyatta National Hospital comprehensive care center. Clinical data was abstracted from electronic medical records for study participants with at least 6 months of follow-up using a structured data abstraction sheet. Results: A total of 250 AYA age 10 to 24 years were included. The median age was 16 years. The median CD4 cell count was 650.6 cells/mm3 (IQR 350.7-884.0). More than half (60.6%) of AYA had a CD4 cell count higher than 500 cells/mm3. Overall, 76.9% of AYA had achieved viral suppression (viral load <1000 copies/ml). There was a significant increase in virologic failure with higher age and late adolescents and young adults were more likely to have a viral load > 1000 copies/ ml p<0.012. Conclusion: The overall virologic suppression in this cohort of AYA was sub-optimal. Both immunological and virologic outcomes were worse among late adolescents (18-19 years) and young adults (20-24 years)

    Holocene bidirectional river system along the Kenya Rift and its influence on East African faunal exchange and diversity gradients

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    © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Dommain, R., Riedl, S., Olaka, L. A., deMenocal, P., Deino, A. L., Owen, R. B., Muiruri, V., Müller, J., Potts, R., & Strecker, M. R. Holocene bidirectional river system along the Kenya Rift and its influence on East African faunal exchange and diversity gradients. Proceedings of the National Academy of Sciences of the United States of America, 119(28),(2022): e2121388119, https://doi.org/10.1073/pnas.2121388119.East Africa is a global biodiversity hotspot and exhibits distinct longitudinal diversity gradients from west to east in freshwater fishes and forest mammals. The assembly of this exceptional biodiversity and the drivers behind diversity gradients remain poorly understood, with diversification often studied at local scales and less attention paid to biotic exchange between Afrotropical regions. Here, we reconstruct a river system that existed for several millennia along the now semiarid Kenya Rift Valley during the humid early Holocene and show how this river system influenced postglacial dispersal of fishes and mammals due to its dual role as a dispersal corridor and barrier. Using geomorphological, geochronological, isotopic, and fossil analyses and a synthesis of radiocarbon dates, we find that the overflow of Kenyan rift lakes between 12 and 8 ka before present formed a bidirectional river system consisting of a “Northern River” connected to the Nile Basin and a “Southern River,” a closed basin. The drainage divide between these rivers represented the only viable terrestrial dispersal corridor across the rift. The degree and duration of past hydrological connectivity between adjacent river basins determined spatial diversity gradients for East African fishes. Our reconstruction explains the isolated distribution of Nilotic fish species in modern Kenyan rift lakes, Guineo-Congolian mammal species in forests east of the Kenya Rift, and recent incipient vertebrate speciation and local endemism in this region. Climate-driven rearrangements of drainage networks unrelated to tectonic activity contributed significantly to the assembly of species diversity and modern faunas in the East African biodiversity hotspot.R.D. was funded by a Smithsonian Human Origins Postdoctoral Fellowship and by Geo.X—the Research Network for Geosciences in Berlin and Potsdam. Fig. 1 D, E, and G and SI Appendix, Figs. S1 and S3 are based on the TanDEM-X Science DEM granted to L.A.O. and S.R. by the German Aerospace Center (DLR) in 2017. L.A.O. acknowledges the Volkswagen Foundation for funding this study with Grant No. 89369. M.R.S. and S.R. were supported by funds from Potsdam University and the Geothermal Development Company of Kenya, and R.B.O. and V.M. were supported by the Hong Kong General Research Fund. We acknowledge support from the National Museums of Kenya and the Kenya Government permission granted by the Ministry of Sports, Culture and the Arts, and by the National Commission for Science, Technology and Innovation (NACOSTI) Permits P/14/7709/683 (to R.P.) and P/16/11924/11448 (to L.A.O.). This work is a contribution of the Olorgesailie Drilling Project, for which support from the National Museums of Kenya, the Oldonyo Nyokie Group Ranch, the Peter Buck Fund for Human Origins Research (Smithsonian Institution), the William H. Donner Foundation, the Ruth and Vernon Taylor Foundation, Whitney and Betty MacMillan, and the Smithsonian Human Origins Program is gratefully acknowledged. LacCore is acknowledged for support in drilling and core storage

    The diversity and evolution of pollination systems in large plant clades: Apocynaceae as a case study

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    Background and Aims Large clades of angiosperms are often characterized by diverse interactions with pollinators, but how these pollination systems are structured phylogenetically and biogeographically is still uncertain for most families. Apocynaceae is a clade of >5300 species with a worldwide distribution. A database representing >10 % of species in the family was used to explore the diversity of pollinators and evolutionary shifts in pollination systems across major clades and regions. Methods The database was compiled from published and unpublished reports. Plants were categorized into broad pollination systems and then subdivided to include bimodal systems. These were mapped against the five major divisions of the family, and against the smaller clades. Finally, pollination systems were mapped onto a phylogenetic reconstruction that included those species for which sequence data are available, and transition rates between pollination systems were calculated. Key Results Most Apocynaceae are insect pollinated with few records of bird pollination. Almost three-quarters of species are pollinated by a single higher taxon (e.g. flies or moths); 7 % have bimodal pollination systems, whilst the remaining approx. 20 % are insect generalists. The less phenotypically specialized flowers of the Rauvolfioids are pollinated by a more restricted set of pollinators than are more complex flowers within the Apocynoids + Periplocoideae + Secamonoideae + Asclepiadoideae (APSA) clade. Certain combinations of bimodal pollination systems are more common than others. Some pollination systems are missing from particular regions, whilst others are over-represented. Conclusions Within Apocynaceae, interactions with pollinators are highly structured both phylogenetically and biogeographically. Variation in transition rates between pollination systems suggest constraints on their evolution, whereas regional differences point to environmental effects such as filtering of certain pollinators from habitats. This is the most extensive analysis of its type so far attempted and gives important insights into the diversity and evolution of pollination systems in large clades
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