No interactions for a collection of Weyl gravitons intermediated by a scalar field

The cross-couplings among several Weyl gravitons (described in the free limit by a sum of linearized Weyl actions) in the presence of a scalar field are studied with the help of the deformation theory based on local BRST cohomology. Under the hypotheses of locality, smoothness of the interactions in the coupling constant, Poincare invariance, (background) Lorentz invariance, and the preservation of the number of derivatives on each field, together with the supplementary assumption that the internal metric defined by the sum of Weyl lagrangians is positively defined, we prove that there are no consistent cross-interactions among different Weyl gravitons in the presence of a scalar field. The couplings of a single Weyl graviton to a scalar field are also discussed.Comment: 53 page

Identification of temperature profile and heat transfer on a dielectric membrane for gas sensors by `COSMOS' program simulation

The application of commercial 3-D software `COSMOS' for the design and thermal analysis of the low power consumption test structures with dielectric membrane for gas microsensors is presented. Within this work, the simulation provides the estimation of the temperature profile on the active area and the whole membrane including the four bridges and the heating efficiency in the temperature range 20-500 °C. Unravelling of the heat loss mechanisms in terms of radiation, convection, conduction by air and solid materials during heat transfer on the dielectric membrane is reported for the first time as a mean to evaluate by 3-D simulation the contribution of technological processes and lay-out design to the total heat losses

No multi-graviton theories in the presence of a Dirac field

The cross-couplings among several massless spin-two fields (described in the free limit by a sum of Pauli-Fierz actions) in the presence of a Dirac field are investigated in the framework of the deformation theory based on local BRST cohomology. Under the hypotheses of locality, smoothness of the interactions in the coupling constant, Poincare invariance, (background) Lorentz invariance and the preservation of the number of derivatives on each field, we prove that there are no consistent cross-interactions among different gravitons in the presence of a Dirac field. The basic features of the couplings between a single Pauli-Fierz field and a Dirac field are also emphasized.Comment: 48 page

Effects of Compost Manure on Soil Microbial Respiration, Plant-Available-Water, Peanut (Arachis hypogaea L.) Yield and Pre-Harvest Aflatoxin Contamination

Peanut production in Zambia is often characterized by low yields and high aflatoxin incidence in harvested kernels. Soil amendments such as farmyard manure have shown potential to increase yields and reduce pre-harvest aflatoxin incidence. The aim of the current study was to evaluate the effects of composted cattle manure on soil properties that relate to yield and pre-harvest aflatoxin contamination of peanut kernels. Research evaluated the effects of composted cattle manure on soil respiration, plant-available water (PAW), peanut yield and pre-harvest aflatoxin contamination in a field experiment conducted in two successive rain-fed cropping seasons starting in December, 2015 and ending in April 2017, in Chongwe District, Zambia. Six (6) levels of compost were incorporated into the top 10 cm of the soil at rates of 0, 4.5, 12.0, 19.5, 27.0, and 34.5 metric tons/ha 1 wk before planting. There was a strong positive relationship between levels of compost and soil microbial respiration (R2=0.84) and PAW (R2=0.86). Secondly, compost manure was associated with increases in pod (R2=0.65) and kernel (R2=0.61) yield. The kernel yield potential of the planted cultivar was achieved at the rate of 12 metric tons per ha. Thirdly, there was a reduction in total aflatoxin levels with increasing levels of compost (R2=0.85). The improvement in peanut yield and the decrease in aflatoxin concentrations in kernels can be attributed to the improvement in soil moisture retention capacity and soil microbial activity arising from manure amendments. This study demonstrated the potential of compost manure to increase soil microbial activity, PAW, peanut yield and minimize aflatoxin contamination at field level

Nursing and midwifery students\u27 experiences and perception of their clinical learning environment in Malawi: A mixed-method study

© 2020 The Author(s). Background: The clinical learning environment is an important part of the nursing and midwifery training as it helps students to integrate theory into clinical practice. However, not all clinical learning environments foster positive learning. This study aimed to assess the student nurses and midwives\u27 experiences and perception of the clinical learning environment in Malawi. Methods: A concurrent triangulation mixed methods research design was used to collect data from nursing and midwifery students. Quantitative data were collected using a Clinical Learning Environment Inventory, while qualitative data were collected using focus group discussions. The Clinical Learning Environment Inventory has six subscales of satisfaction, involvement, individualisation, innovation, task orientation and personalisation. The focus group interview guide had questions about clinical learning, supervision, assessment, communication and resources. Quantitative data were analysed by independent t-test and multivariate linear regression and qualitative data were thematically analysed. Results: A total of 126 participants completed the questionnaire and 30 students participated in three focus group discussions. Satisfaction subscale had the highest mean score (M = 26.93, SD = 4.82) while individualisation had the lowest mean score (M = 18.01, SD =3.50). Multiple linear regression analysis showed a statistically significant association between satisfaction with clinical learning environment and personalization (β = 0.50, p = \u3c 0.001), and task orientation (β =0.16 p = \u3c 0.05). Teaching and learning resources, hostile environment, poor relationship with a qualified staff, absence of clinical supervisors, and lack of resources were some of the challenges faced by students in their clinical learning environment. Conclusion: Although satisfaction with clinical learning environment subscale had the highest mean score, nursing and midwifery students encountered multifaceted challenges such as lack of resources, poor relationship with staff and a lack of support from clinical teachers that negatively impacted on their clinical learning experiences. Training institutions and hospitals need to work together to find means of addressing the challenges by among others providing resources to students during clinical placement