A novel approach to steganone analogues via metal-mediated cyclisations

Transition metal mediated cyclisation reactions are utilised in the synthesis of analogues of the naturally-occurring antileukemic bisbenzocyclooctadiene lignan, steganone. The first approach involves the metal-mediated [2+2+2] cycloaddition of a rationally designed linear 1,9-diyne with a hindered alkyne. This diyne is formed via a convergent synthetic sequence starting from 3,4,5-trimethoxybenzaldehyde and paraconic acid. The cyclisation reaction proceeds diastereospecifically to give the atropisomer relevant to the natural product. The cycloadduct thus formed has been elaborated to give several novel analogues of steganone. The reaction of this diyne and a model diyne with a chromium carbenoid complex is investigated. This methodology is found to be unsuitable to the formation of this ring system. A family of macrocycles is postulated, in which one aryl ring present in steganone is replaced with an enediyne moiety. It is suggested these will furnish steganone analogues after Bergman cycloaromatisation. A number of approaches to this class of compound are described. Several advanced linear macrocycle precursors are synthesised, and their metal-mediated cyclisation reactions are investigated. The final approach to steganone analogues involves cascade carbopalladation of a linear bromoenyne. This bromoenyne is synthesised via a similar synthetic sequence to the diyne previously mentioned. The co-cyclisation of this bromoenyne with trimethylsilylethyne under conditions of palladium catalysis is investigated

A study on the impact of social media marketing in the event industry: Executing a marketing plan

Marketing is a large part of growing one’s business or event. The objective of this study was to gain an understanding of how social media marketing increases brand loyalty, attendance, and engagement within current and potential guests over traditional event marketing methods. Through this study a data collection survey for the University of Arkansas’ Hospitality Management annual event Students Mastering the Art of Hospitality (SMASH) to gather information on the effectiveness of e social media marketing’s influence on their attendees. Unfortunately, due to a global pandemic SMASH was canceled and the researcher and honor’s committee thought it to be best to create a social media marketing plan for the 2022 event year because the appropriate data could not be collected. Through this marketing plan, one can see how social media additives to the SMASH marketing plan will create a stronger engagement with guests and grow the event

Emulating Simulations of Cosmic Dawn for 21cm Power Spectrum Constraints on Cosmology, Reionization, and X-ray Heating

Current and upcoming radio interferometric experiments are aiming to make a statistical characterization of the high-redshift 21cm fluctuation signal spanning the hydrogen reionization and X-ray heating epochs of the universe. However, connecting 21cm statistics to underlying physical parameters is complicated by the theoretical challenge of modeling the relevant physics at computational speeds quick enough to enable exploration of the high dimensional and weakly constrained parameter space. In this work, we use machine learning algorithms to build a fast emulator that mimics expensive simulations of the 21cm signal across a wide parameter space to high precision. We embed our emulator within a Markov-Chain Monte Carlo framework, enabling it to explore the posterior distribution over a large number of model parameters, including those that govern the Epoch of Reionization, the Epoch of X-ray Heating, and cosmology. As a worked example, we use our emulator to present an updated parameter constraint forecast for the Hydrogen Epoch of Reionization Array experiment, showing that its characterization of a fiducial 21cm power spectrum will considerably narrow the allowed parameter space of reionization and heating parameters, and could help strengthen Planck's constraints on $\sigma_8$. We provide both our generalized emulator code and its implementation specifically for 21cm parameter constraints as publicly available software.Comment: 22 pages, 9 figures; accepted to Ap

Autoavaliação de funções auditivas em trabalhadores expostos a solventes

OBJETIVO: Comparar o desempenho das atividades diárias relacionadas a funções do sistema auditivo periférico e central entre trabalhadores expostos e não expostos a solventes. MÉTODOS: Participaram do estudo 96 trabalhadores, sendo 48 expostos a solventes e 48 não expostos, pareados por escolaridade, idade e sexo. Os procedimentos de avaliação incluíram: audiometria de tons puros (500 a 8.000 Hz), para avaliar o sistema auditivo periférico; teste de Random Gap Detection, para avaliar o sistema auditivo central; e o Amsterdam Inventory for Auditory Disability and Handicap, para estudar a performance em atividades da vida diária que envolvem a audição, por meio de autoavaliação. Teste t de student e a análise de covariância (ANCOVA) foram utilizados. Foram calculadas as correlações de Pearson entre os resultados dos três testes. RESULTADOS: Sujeitos expostos a solventes tiveram limiares auditivos significativamente piores na orelha direita que os sujeitos não expostos. Apresentaram também resultados significativamente piores no teste de Random Gap Detection e funcionamento autorreportado significativamente mais alterado que os sujeitos não expostos. Foi observada correlação significativa entre os resultados do Amsterdam Inventory for Auditory Disability and Handicap e a média binaural dos limiares auditivos e com os resultados do teste de Random Gap Detection. CONCLUSÕES: A exposição a solventes está associada com as dificuldades da vida diária relacionadas com as funções do sistema auditivo periférico e central.OBJECTIVE: To compare hearing performance relating to the peripheral and central auditory system between solvent-exposed and non-exposed workers. METHODS: Forty-eight workers exposed to a mixture of solvents and 48 non-exposed control subjects of matched age, gender and educational level were selected to participate in the study. The evaluation procedures included: pure-tone audiometry (500 - 8,000 Hz), to investigate the peripheral auditory system; the Random Gap Detection test, to assess the central auditory system; and the Amsterdam Inventory for Auditory Disability and Handicap, to investigate subjects' self-reported hearing performance in daily-life activities. A Student t test and analyses of covariance (ANCOVA) were computed to determine possible significant differences between solvent-exposed and non-exposed subjects for the hearing level, Random Gap Detection test and Amsterdam Inventory for Auditory Disability and Handicap. Pearson correlations among the three measures were also calculated. RESULTS: Solvent-exposed subjects exhibited significantly poorer hearing thresholds for the right ear than non-exposed subjects. Also, solvent-exposed subjects exhibited poorer results for the Random Gap Detection test and self-reported poorer listening performance than non-exposed subjects. Results of the Amsterdam Inventory for Auditory Disability and Handicap were significantly correlated with the binaural average of subject pure-tone thresholds and Random Gap Detection test performance. CONCLUSIONS: Solvent exposure is associated with poorer hearing performance in daily life activities that relate to the function of the peripheral and central auditory system.OBJETIVO: Comparar el desempeño de las actividades diarias relacionadas a funciones del sistema auditivo periférico y central entre trabajadores expuestos y no expuestos a solventes. MÉTODOS: Participaron del estudio, 96 trabajadores, siendo 48 expuestos a solventes y no expuestos, pareados por escolaridad, edad y sexo. Los procedimientos de evaluación incluyeron: audiometría de sonidos puros (500 a 8.000 Hz), para evaluar el sistema auditivo periférico; prueba de Random Gap Detection, para evaluar el sistema auditivo central; y el Amsterdam Inventory for Auditory Disability and Handicap, para estudiar la performance en actividades de la vida diaria que envuelven la audición, por medio de auto-evaluación. Prueba t de Student y el análisis de covarianza (ANCOVA) fueron utilizados. Se calcularon las correlaciones de Pearson entre los resultados de las tres pruebas. RESULTADOS: Sujetos expuestos a solventes tuvieron umbrales auditivos significativamente peores en el oído derecho que los sujetos no expuestos. Se presentaron también resultados significativamente peores en la prueba de Random Gap Detection y funcionamiento auto-reportado significativamente más alterado que los sujetos no expuestos. Se observó correlación significativa entre los resultados del Amsterdam Inventory for Auditory Disability and Handicap y el promedio binaural de los umbrales auditivos y con los resultados de la prueba de Random Gap Detection. CONCLUSIONES: La exposición a solventes está asociada con las dificultades de la vida diaria relacionadas con las funciones del sistema auditivo periférico y central

Improved Hydrogeophysical Parameter Estimation from Empirical Mode Decomposition Processed Ground Penetrating Radar Data

Various techniques have been designed to maximize the use of ground penetrating radar (GPR) as an exploration tool. Improvements in signal processing are expected to further facilitate the accuracy of parameters derived from using GPR in certain geologic environments. Common-offset GPR data were collected at the Marine Corps Air Station (MCAS) in Beaufort, South Carolina, and dielectric constants were calculated following the application of the empirical mode decomposition (EMD) for dewowing GPR traces. Conventional signal processing is applied to the GPR traces to provide hydrogeophysical parameter estimates such as volumetric water content, porosity, and hydraulic conductivity. The results are validated using a coincident vertical radar profile, existing hydraulic data from direct measurements, and comparing EMD derived parameters with those non-EMD derived. The results of the comparison between the EMD and non-EMD methods show improved hydrogeophysical estimations from the EMD processed data. Dielectric constant (k) values from the non-EMD method are outside the range of the values for all geologic materials (k#40). The subsequent parameter estimates using dielectric constants derived from non-EMD processed data yield erroneous results therefore justifying the use of EMD as a method in dewowing GPR data for quantitative analyses

Temporal variation in cardiovascular disease risk predicted by albuminuria: an opportunity for clinical intervention?

Albuminuria predicts cardiovascular disease (CVD) events but it is likely to vary over time in a nonlinear fashion. The aim of this study was to estimate the potentially differing predictive effect of albuminuria on the risk of CVD or related death over time. Data were from a cohort study of 3505 predominately indigenous adults from remote communities in Queensland, Australia, 1999-2006. Cox Proportional Hazards model analysis of the predictive effects of urinary albumin creatinine ratio on the risk of CVD or CVD-related death was undertaken for incident and prevalent CVD. Analyses sequentially removed those who had a cardiovascular event or related death for the first year through to six years. The baseline prevalence of microalbuminuria was 21.2% and for macroalbuminuria 6.7%. The incidence of CVD was 92 in 13,812 person-years. Microalbuminuria predicted incident CVD with a Hazard Ratio (HR) of 3.0 (95% CI 1.83 - 4.96) and for macroalbuminuria HR 10.8 (95% CI 6.58 - 17.68) and for those with pre-existing CVD, HR 2.6 (95% CI 1.65 - 3.97) and HR 9.7 (95% CI 6.38 - 14.82) respectively. People with macroalbuminuria who survived the first three years had a crude HR of an incident cardiovascular event or death of 13.0 (95% CI 6.45 - 26.39) to a peak of 32.3 (95% CI 8.55 - 121.77) for those who survived the first five years. The hazard appeared to drop in the 6th year although this is based on small numbers.The first three years after finding macroalbuminuria provide a potential window opportunity to actively manage the risk of incident CVD before the risk elevates

Empirical Mode Decomposition Operator for Dewowing GPR Data

Signal processing tools available to ground penetrating radar data used for shallow subsurface imaging and hydrogeophysical parameter estimation are significantly handled using the same tools available to seismic reflection data. Overall, the same tools produce interpretable images from both data types, but particular noise (wow noise) in electromagnetic data must be removed before stable and accurate quantitative results can be produced. Wow noise is an inherent, nonlinear electromagnetic interference and a significant component of GPR data. Further, the nonlinear and non-stationary nature of wow noise provides a strong argument for preprocessing radar traces with time-domain operators. Time-domain operators designed for nonlinear signals are under increasing development for both electromagnetic and acoustic signal processing. This work demonstrates optimal wow noise removal from ground penetrating radar data using the empirical mode decomposition. The technique provides a data-driven approach to empirically dewowing GPR data

Discrete-Ordinates Modelling of the Radiative Heat Transfer in a Pilot-Scale Rotary Kiln

This paper presents work focused on the development, evaluation and use of a 3D model for investigation of the radiative heat transfer in rotary kilns. The model applies a discrete-ordinates method to solve the radiative transfer equation considering emission, absorption and scattering of radiation by gas species and particles for cylindrical and semi-cylindrical enclosures. Modelling input data on temperature, particle distribution and gas composition in the radial, axial and angular directions are experimentally gathered in a down-scaled version of a rotary kiln. The model is tested in its capability to predict the radiative intensity and heat flux to the inner wall of the furnace and good agreement was found when compared to measurements. Including the conductive heat transfer through the furnace wall, the model also satisfactorily predicts the intermediate wall temperature. The work also includes a first study on the effect of the incident radiative heat flux to the different surfaces while adding a cold bed material. With further development of the model, it can be used to study the heat transfer in full-scale rotary kilns

Deep learning from 21-cm tomography of the Cosmic Dawn and Reionization

The 21-cm power spectrum (PS) has been shown to be a powerful discriminant of reionization and cosmic dawn astrophysical parameters. However, the 21-cm tomographic signal is highly non-Gaussian. Therefore there is additional information which is wasted if only the PS is used for parameter recovery. Here we showcase astrophysical parameter recovery directly from 21-cm images, using deep learning with convolutional neural networks (CNN). Using a data base of 2D images taken from 10 000 21-cm light-cones (each generated from different cosmological initial conditions), we show that a CNN is able to recover parameters describing the first galaxies: (i) T-vir, their minimum host halo virial temperatures (or masses) capable of hosting efficient star formation; (ii) zeta, their typical ionizing efficiencies; (iii) L-X/SFR, their typical soft-band X-ray luminosity to star formation rate; and (iv) E-0, the minimum X-ray energy capable of escaping the galaxy into the IGM. For most of their allowed ranges, log T-vir and log L-X/SFR are recovered with < 1 per cent uncertainty, while zeta and E-0 are recovered with similar to 10 per cent uncertainty. Our results are roughly comparable to the accuracy obtained from Monte Carlo Markov Chain sampling of the PS with 21CMMC for the two mock observations analysed previously, although we caution that we do not yet include noise and foreground contaminants in this proof-of-concept study