Numerical Modeling and Evaluation of Involute Curve Length of a Spur Gear Tooth to Maintain Constant Velocity Ratio While in Motion

Numerical modeling and values of the involutes curve length for a spur gear has been carried out using polar coordinate principles and application of calculus theorems. A set of values for base radius of the gear were considered from 10mm, 20mm, 30mm, 40mm and 50mm. The study also considered a pressure angle of 10°, 20°, 30°, 40°, and 50° for this set of values. The result of the length of involutes curve obtained at a pressure angle of 10° showed a significant increase in the length of the curve generated as the base radius increases that is at10° and for the set of the base radius values, the length obtained are:0.1555mm,0.311mm,0.4665mm,0.622mm and 0.7775mm. The result also revealed that at higher pressure angle of 50°, a better length of the curve was equally generated as seen from the plot.That is at 50° and with the base radius of 10mm, 20mm, 30mm, 40mm, and 50mm, the corresponding length of involutes are 7.1014mm, 14.203mm, 21.3045mm, 28.406mm and 35.5075mm. This equally validate the direct proportionality of length of curve as the square of tan a from equation

Associations between Cognition, Gender and Monocyte Activation among HIV Infected Individuals in Nigeria.

The potential role of gender in the occurrence of HIV-related neurocognitive impairment (NCI) and associations with markers of HIV-related immune activity has not been previously examined. In this study 149 antiretroviral-naïve seropositive subjects in Nigeria (SP, 92 women and 57 men) and 58 seronegative (SN, 38 women and 20 men) were administered neuropsychological testing that assessed 7 ability domains. From the neuropsychological test scores was calculated a global deficit score (GDS), a measure of overall NCI. Percentages of circulating monocytes and plasma HIV RNA, soluble CD163 and soluble CD14 levels were also assessed. HIV SP women were found to be younger, more educated and had higher CD4+ T cell counts and borderline higher viral load measures than SP men. On the neuropsychological testing, SP women were more impaired in speed of information processing and verbal fluency and had a higher mean GDS than SN women. Compared to SP men, SP women were also more impaired in speed of information processing and verbal fluency as well as on tests of learning and memory. Numbers of circulating monocytes and plasma sCD14 and sCD163 levels were significantly higher for all SP versus all SN individuals and were also higher for SP women and for SP men versus their SN counterparts. Among SP women, soluble CD14 levels were slightly higher than for SP men, and SP women had higher viral load measurements and were more likely to have detectable virus than SP men. Higher sCD14 levels among SP women correlated with more severe global impairment, and higher viral load measurements correlated with higher monocyte numbers and sCD14 and sCD14 levels, associations that were not observed for SP men. These studies suggest that the risk of developing NCI differ for HIV infected women and men in Nigeria and, for women, may be linked to effects from higher plasma levels of HIV driving activation of circulating monocytes

Diversity of indigenous arbuscular mycorrhizal fungi in rhizosphere of upland rice (Oryza sativa L.) varieties in Southwest Nigeria

Article Details: Received: 2020-02-05      |      Accepted: 2020-05-07      |      Available online: 2020-06-30https://doi.org/10.15414/afz.2020.23.02.42-48 Arbuscular mycorrhizal fungi (AMF) have the potential to increase crop productivity and play a key role in the functioning and sustainability of most agroecosystems. However, limited information is available on the divervisity of AMF associated with upland rice varieties in Southwest Nigeria. Field survey was conducted to investigate colonization and diversity of AMF in 13 upland rice varieties commonly grown in Southwest Nigeria. Root and soil samples were collected from rice fields in 2012. The results showed natural root colonization of all the rice varieties by AMF with highest root colonization in ITA 157and Ofada. The spore densities retrieved from the different rhizospheres were relatively high, varying from 13 spores in UORW 111 to 174 spores in Ofada with a mean of 67.6 spores per 20 g dry soil. Glomus was observed to be the most abundant AMF genus. Funneliformis mosseae was the most frequently occurring AMF species (96.2%) with relative density (RD) of 32.2%, followed by Glomus intraradices, Claroideoglomus etunicatum, and Glomus clareium. This study showed that AMF naturally colonized the roots of these rice varieties and diversity of different AMF genera in rice rhizosphere. This study will help draw attention to natural colonization of AMF in rice producing areas of Nigeria that can influence future possibility of using inocula of the dominant AMF species in upland rice cultivation.Keywords: Arbuscular mycorrhizal fungi, community structure, diversity, upland rice, spore densityReferences ADEYEMI, N.O. et al. (2020). Effect of commercial arbuscular mycorrhizal fungi inoculant on growth and yield of soybean under controlled and natural field conditions. Journal of Plant Nutrition, 43(4), 487–499, DOI: https://doi.org/10.1080/019041 67.2019.1685101 ADEYEMI, N.O. et al. (2019). Identification and relative abundance of native arbuscular mycorrhizal fungi associated with oil-seed crops and maize (Zea mays L.) in derived savannah of Nigeria. Acta fytotechn zootechn, 22(3), 84–89. DOI: https://doi.org/10.15414/afz.2019.22.03.84-89 ADEYEMI, N. et al. (2017). Yield and yield attributes responses of soybean (Glycine max L. Merrill) to elevated CO2 and arbuscular mycorrhizal fungi inoculation in the humid transitory rainforest. Notulae Scientia Biologicae, 9(2), 233–241. DOI: https://doi.org/10.15835/nsb9210002 BARBER, N.A. et al. (2013). Linking agricultural practices, mycorrhizal fungi, and traits mediating plant-insect interactions. Ecol Appl, 23(7), 1519–1530.BŁASZKOWSKI, J. (2012) Glomeromycota. Kraków: W. Szafer Institute of Botany, Polish Academy of Sciences. BOUYOUCOS, G.H. (1951). A recalibration of the hydrometer method for testing mechanical analysis of soils. Agronomy Journal, 43,434–438.BRUNDRETT, M.C. and TEDERSOO, L. (2018) Evolutionary history of mycorrhizal symbioses and global host plant diversity. New Phytol, 220,1108–1115. CAMPOS-SORIANO, L. et al. (2010). Activation of basal defense mechanisms of rice plants by Glomus intraradices does not affect the arbuscular mycorrhizal symbiosis. New Phytol, 188(2), 597–614. CHEN, M. et al. (2018) Beneficial services of arbuscular mycorrhizal fungi – from ecology to application. Frontiers in Plant Science, 9. DOI: https://doi.org/10.3389/fpls.2018.01270DAVISON, J. et al. (2015). Global assessment of arbuscular mycorrhizal fungus diversity reveals very low endemism. Science, 349, 970–973. DE ANDRADE-JÚNIOR, J.A. et al. (2018) Fixação de carbono em sistemas agroecológicos na região do Vale do São Patrício, Goiás. Científica – Multidiscip J, 5, 85–98. DE MOURA, J.B. et al. (2018) Taxa de colonização micorrízica sob diferentes sistemas de cultivo no cerrado em cana-deaçúcar. Diálogos & Ciência, 2, 60–66. GIANINAZZI, S. et al. (2010). Agroecology: The key role of arbuscular mycorrhizas in ecosystem services. Mycorrhiza, 20(8), 519–530. INVAM (2018). International culture collection of (vesicular) arbuscular mycorrhizal fungi. Morgantown: West Virginia University. HAZARD, C. et al. (2013). The role of local environment and  geographical distance in determining community composition of arbuscular mycorrhizal fungi at the landscape scale. The ISME Journal, 7, 498–508. JIANG, Y.N. et al. (2017). Plants transfer lipids to sustain colonization by mutualistic mycorrhizal and parasitic fungi. Science, 356, 1172–1175. JOHNSON, N.C. (2010). Resource stoichiometry elucidates the structure and function of arbuscular mycorrhizas across scales. New Phytol, 185(3), 631–647. LEKBERG, Y. and KOIDE, R.T. (2005). Is plant performance limited by abundance of arbuscular mycorrhizal fungi? A metaanalysis of studies published between 1988 and 2003. New Phytol, 168(1). LIN, X. et al. (2012). Long-term balanced fertilization decreases arbuscular mycorrhizal fungal diversity in an arable soil in north China revealed by 454 pyrosequencing. Environmental Science & Technology, 46, 5764–5771. LUGINBUEHL, L.H. et al. (2017). Fatty acids in arbuscular mycorrhizal fungi are synthesized by the host plant. Science, 356, 1175–1178. LUMINI, E. et al. (2011). Different farming and water regimes in Italian rice fields affect arbuscular mycorrhizal fungal soil communities. Ecol Appl, 21(5), 1696–1707.OEHL, F. et al. (2010). Soil type and land use intensity determine the composition of arbuscular mycorrhizal fungal communities. Soil Biology and Biochemistry, 42, 724–738. OEHL, F. et al. (2017) Diversity and biogeography of arbuscular mycorrhizal fungi in agricultural soils. Biol Fertil Soils, (53), 777–797. PEYRET-GUZZON, M. et al. (2016). Arbuscular mycorrhizal fungal communities and Rhizophagus irregularis populations shift in response to short term ploughing and fertilisation in a buffer strip. Mycorrhiza, 26, 33–46. PHILLIPS, J.M. and HAYMAN, D.S. (1970). Improved procedures for clearing roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection. Trans Br Mycol Soc., 55,158–IN18. PIVATO, B. et al. (2007). Medicago species affect the community composition of arbuscular myccorhizal fungi associated with roots. New Phytologist 176, 197–210. RILLIG, M.C. and MUMMEY, D.L. (2006). Mycorrhizas and soil structure. New Phytol, 171(1), 41–53. SILVA-FLORES, P. et al. (2019) Factors affecting arbuscular mycorrhizal fungi spore density in the Chilean Mediterraneantype ecosystem. J Soil Sci Plant Nutr, 19, 42–50. SMITH, S.E. and READ, D.J. (2008). Mycorrhizal symbiosis. 3rd ed., New York: Academic Press. SNOECK, D. et al. (2010). Temporal changes in VAM fungi in the cocoa agroforestry systems of central Cameroon. Agroforestry Syst., 78, 323–328. SOUZA, B.R. et al. (2016) Arbuscular mycorrhizal fungi as indicative of soil quality in conservation systems in the region of vale do São Patrício, Goiás. Int J Curr Res, 8, 43307–43311.VALLINO, et al. (2014). Rice flooding negatively impacts root branching and arbuscular mycorrhizal colonization, but not fungal viability. Plant Cell Environ, 37(3), 557–572. VAN Der HEIJDEN, M.G. et al. (2015) Mycorrhizal ecology and evolution: the past, the present, and the future. New Phytol 205, 1406–1423. VENTURA, M.V.A, et al. (2018) Influence of arbuscular mycorrhizal fungi in the establishment of pre-broken sugar cane. Poljoprivreda i Sumarstvo, 64,149–157. WALKLEY, A., and BLACK, I.A. (1934). An examination of Degtjareff method for determining soil organic matter and proposed modification of the chromic acid in soil analysis.1. Experimental soil science, 79, 459–465. WANG, Y.T. et al. (2015). Community dynamics of arbuscular mycorrhizal fungi in high-input and intensively irrigated rice cultivation systems. Appl Environ Microbiol, 81(8), 2958–2965. ZHANG, S.J. et al. (2015). Is resource allocation and grain yield of rice altered by inoculation with arbuscular mycorrhizal fungi? J Plant Ecol, 8(4), 436–448

Welcome to the House of Fun: Work Space and Social Identity

Following the diffusion of HRM as the dominant legitimating managerial ideology, some employers have started to see the built working environment as a component in managing organisational culture and employee commitment. A good example is where the work space is designed to support a range of officially encouraged ‘fun’ activities at work. Drawing on recent research literature and from media reports of contemporary developments, this paper explores the consequences of such developments for employees’ social identity formation and maintenance, with a particular focus on the office and customer service centre. Our analysis suggests that management’s attempts to determine what is deemed fun may not only be resented by workers because it intrudes on their existing private identities but also because it seeks to re-shape their values and expression

Experimental and Mathematical Modeling for Prediction of Tool Wear on the Machining of Aluminium 6061 Alloy by High Speed Steel Tools

In recent machining operation, tool life is one of the most demanding tasks in production process, especially in the automotive industry. The aim of this paper is to study tool wear on HSS in end milling of aluminium 6061 alloy. The experiments were carried out to investigate tool wear with the machined parameters and todevelopedmathematicalmodelusingresponsesurface methodology.Thevariousmachiningparametersselected fortheexperimentarespindlespeed(N),feedrate(f),axialdepthofcut(a)andradialdepthofcut(r).Theexperimentwasdesignedusingcentralcompositedesign(CCD) inwhich31sampleswererunonSIEG3/10/0010CNCend milling machine. After each experiment the cutting tool wasmeasuredusingscanningelectronmicroscope(SEM). Theobtainedoptimummachiningparametercombination arespindlespeedof2500rpm,feedrateof200mm/min, axialdepthofcutof20mm,andradialdepthofcut1.0mm wasfoundouttoachievedtheminimumtoolwearas0.213 mm. The mathematical model developed predicted the toolwearwith99.7%whichiswithintheacceptableaccuracyrangefortoolwearpredictio

The Rachel Carson Letters and the Making of Silent Spring

Environment, conservation, green, and kindred movements look back to Rachel Carson’s 1962 book Silent Spring as a milestone. The impact of the book, including on government, industry, and civil society, was immediate and substantial, and has been extensively described; however, the provenance of the book has been less thoroughly examined. Using Carson’s personal correspondence, this paper reveals that the primary source for Carson’s book was the extensive evidence and contacts compiled by two biodynamic farmers, Marjorie Spock and Mary T. Richards, of Long Island, New York. Their evidence was compiled for a suite of legal actions (1957-1960) against the U.S. Government and that contested the aerial spraying of dichlorodiphenyltrichloroethane (DDT). During Rudolf Steiner’s lifetime, Spock and Richards both studied at Steiner’s Goetheanum, the headquarters of Anthroposophy, located in Dornach, Switzerland. Spock and Richards were prominent U.S. anthroposophists, and established a biodynamic farm under the tutelage of the leading biodynamics exponent of the time, Dr. Ehrenfried Pfeiffer. When their property was under threat from a government program of DDT spraying, they brought their case, eventually lost it, in the process spent US$100,000, and compiled the evidence that they then shared with Carson, who used it, and their extensive contacts and the trial transcripts, as the primary input for Silent Spring. Carson attributed to Spock, Richards, and Pfeiffer, no credit whatsoever in her book. As a consequence, the organics movement has not received the recognition, that is its due, as the primary impulse for Silent Spring, and it is, itself, unaware of this provenance

Organic waste substrates induce important shifts in gut microbiota of black soldier fly (Hermetia illucens L.) : coexistence of conserved, variable, and potential pathogenic microbes

The sustainable utilization of black soldier fly (BSF) for recycling organic waste into nutrient-rich biomass, such as high-quality protein additive, is gaining momentum, and its microbiota is thought to play important roles in these processes. Several studies have characterized the BSF gut microbiota in different substrates and locations; nonetheless, in-depth knowledge on community stability, consistency of member associations, pathogenic associations, and microbe–microbe and host–microbe interactions remains largely elusive. In this study, we characterized the bacterial and fungal communities of BSF larval gut across four untreated substrates (brewers’ spent grain, kitchen food waste, poultry manure, and rabbit manure) using 16S and ITS2 amplicon sequencing. Results demonstrated that substrate impacted larval weight gain from 30 to 100% gain differences among diets and induced an important microbial shift in the gut of BSF larvae: fungal communities were highly substrate dependent with Pichia being the only prevalent genus across 96% of the samples; bacterial communities also varied across diets; nonetheless, we observed six conserved bacterial members in 99.9% of our samples, namely, Dysgonomonas, Morganella, Enterococcus, Pseudomonas, Actinomyces, and Providencia. Among these, Enterococcus was highly correlated with other genera including Morganella and Providencia. Additionally, we showed that diets such as rabbit manure induced a dysbiosis with higher loads of the pathogenic bacteria Campylobacter. Together, this study provides the first comprehensive analysis of bacterial and fungal communities of BSF gut across untreated substrates and highlights conserved members, potential pathogens, and their interactions. This information will contribute to the establishment of safety measures for future processing of BSF larval meals and the creation of legislation to regulate their use in animal feeds.The Canadian International Development Research Centre (IDRC) and the Australian Centre for International Agricultural Research (ACIAR), Norwegian Agency for Development Cooperation, the Section for Research, Innovation, and Higher Education (CAP-Africa), the Netherlands Organization for Scientific Research, WOTRO Science for Global Development (NWO-WOTRO) and The Rockefeller Foundation through the International Centre of Insect Physiology and Ecology (icipe).http://www.frontiersin.org/Microbiologyam2022BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Optical-resolution photoacoustic microscopy of angiogenesis in a transgenic mouse model

A major obstacle in studying angiogenesis is the inability to noninvasively image neovascular development in an individual animal. We applied optical-resolution photoacoustic microscopy (OR-PAM) to determine the kinetics of hypoxia-inducible factor-1 (HIF-1)-mediated angiogenesis in a transgenic mouse model. During continuous 30-day activation of HIF-1α, we used OR-PAM to monitor alterations in microvasculature in transgenic mice compared to nontransgenic mice. OR-PAM has demonstrated the potential to precisely monitor antiangiogenic therapy of human cancers, allowing for rapid determinations of therapeutic efficacy or resistance