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

On Optimal Harvesting in Stochastic Environments: Optimal Policies in a Relaxed Model

This paper examines the objective of optimally harvesting a single species in a stochastic environment. This problem has previously been analyzed in Alvarez (2000) using dynamic programming techniques and, due to the natural payoff structure of the price rate function (the price decreases as the population increases), no optimal harvesting policy exists. This paper establishes a relaxed formulation of the harvesting model in such a manner that existence of an optimal relaxed harvesting policy can not only be proven but also identified. The analysis embeds the harvesting problem in an infinite-dimensional linear program over a space of occupation measures in which the initial position enters as a parameter and then analyzes an auxiliary problem having fewer constraints. In this manner upper bounds are determined for the optimal value (with the given initial position); these bounds depend on the relation of the initial population size to a specific target size. The more interesting case occurs when the initial population exceeds this target size; a new argument is required to obtain a sharp upper bound. Though the initial population size only enters as a parameter, the value is determined in a closed-form functional expression of this parameter.Comment: Key Words: Singular stochastic control, linear programming, relaxed contro

Higher fiber complementary food alters fecal microbiota composition and normalizes stool form in Malawian children: a randomized trial

Dietary fiber favorably modulates gut microbiota and may be protective against diarrhea in sub-Saharan Africa where rates in infants and young children are high. Soybean hull is high in fiber and accessible in rural Africa; however, its use in complementary feeding has not been evaluated. The objective of this study was to determine the acceptability and feasibility of a soybean, soy hull fiber, and maize (SFM) blend food; the primary outcome was compliance to the feeding protocol. Secondary outcomes were stool form and frequency, fecal microbiota composition, growth and dietary intake. In a parallel, single-blind study, children 6-36 months of age from the Lilongwe district of Malawi were randomized to receive daily SFM (n=69) or maize only (n=10) porridge (phala) for 6 months. Anthropometrics were measured monthly, and compliance, stool frequency, and stool form, weekly. At baseline, 3-month, and 6-month (study end) time points, dietary intake (24-h recall) was assessed, and fecal samples were collected. Fecal DNA was analyzed by Real-Time polymerase chain reaction (PCR) for microbes of interest and 16S rRNA gene amplicon sequencing. Mothers accessed the acceptability and feasibility of the study foods at study end. Mothers reported excellent compliance to feeding the SFM porridge, rated it more acceptable than maize, and noted improved appetite, weight, and stool consistency of their children. Stool frequency at baseline (2±1 stools/d) was unchanged with intervention; however, there were significantly fewer diarrhea-type stools reported during study months 4-6 vs. 1-3 for the SFM group, whereas no improvement was seen for the maize group. At study end, the fecal abundance of Akkermansia muciniphila was enriched in children receiving the SFM, compared to maize (p<0.05), and a trend for increased Faecalibacterium prausnitzii (p=0.07) was seen. A comparison of fecal microbiota composition using linear discriminant analysis effect size (LEfSe) showed notable differences in numerous taxa in the SFM group compared to baseline, whereas the maize comparator exhibited fewer changes. Fiber intake was higher for the SFM group, compared to maize at 6 months (13.7±3.8 vs. 8.4±4.5 g/day, p<0.01). Weight-for-height and BMI-for-age Z-scores were significantly higher for the SFM group. In young Malawian children, feeding a blend of soybean, soy hulls and maize reduced diarrhea-type stools and increased the abundance of Akkermansia muciniphila, a bacterial species involved in maintaining intestinal health, and thus may provide a feasible means of improving wellness in children in resource-poor settings through the modulation of microbiota composition

Taylor dispersion with absorbing boundaries: A Stochastic Approach

We describe how to solve the problem of Taylor dispersion in the presence of absorbing boundaries using an exact stochastic formulation. In addition to providing a clear stochastic picture of Taylor dispersion, our method leads to closed-form expressions for all the moments of the convective displacement of the dispersing particles in terms of the transverse diffusion eigenmodes. We also find that the cumulants grow asymptotically linearly with time, ensuring a Gaussian distribution in the long-time limit. As a demonstration of the technique, the first two longitudinal cumulants (yielding respectively the effective velocity and the Taylor diffusion constant) as well as the skewness (a measure of the deviation from normality) are calculated for fluid flow in the parallel plate geometry. We find that the effective velocity and the skewness (which is negative in this case) are enhanced while Taylor dispersion is suppressed due to absorption at the boundary.Comment: 4 pages, 1 figur

A comparison of vitamin D and cathelicidin (LL-37) levels between patients with active TB and their healthy contacts in a high HIV prevalence setting: a prospective descriptive study

BACKGROUND: Studies from Asia and Europe indicate an association between vitamin D deficiency and susceptibility to TB. We performed an observational case-control study to determine vitamin D and cathelicidin (LL-37) levels and their association with active TB in newly diagnosed and microbiologically confirmed adult TB patients in Zambia, a high HIV prevalence setting. METHODS: Both total vitamin D and LL-37 were measured using ELISA from serum and supernatant isolated from cultured whole blood that was stimulated with heat-killed Mycobacterium tuberculosis. Statistical analysis was performed using STATA statistical software version 12. RESULTS: The median vitamin D in TB patients and healthy contacts was 28.7 (19.88-38.64) and 40.8 (31.2-49.44) ng/ml, respectively (p<0.001). The median LL-37 in TB patients compared with healthy contacts was 1.87 (2.74-8.93) and 6.73 (5.6-9.58) ng/ml, respectively (p=0.0149). Vitamin D correlation with LL-37 in healthy contacts was R2=0.7 (95% CI 0.566 to 0.944), p<0.0001. Normal vitamin D significantly predicted a healthy status (OR 4.06, p=0.002). CONCLUSIONS: Significantly lower levels of vitamin D and LL-37 are seen in adults with newly diagnosed active TB. Longitudinal studies across various geographical regions are required to accurately define the roles of vitamin D and LL-37 in preventive and TB treatment outcomes

The Importance of Handball in the Development of High School Pupils

The aim of the research consists of identifying the opinions of pupils, parents, and teachers from high-school education institutions on the main aspects of the handball game within physical education and sports lessons and training. The present research is of ascertaining – ameliorative type, carried out on a sample of 110 people (pupils, parents, and specialized teachers) from four educational institutions in Campulung Moldovenesc, Romania: National College «Dragos Voda», Bucovina Forest College, National Military College «Stefan Cel Mare» and Technological High School no.1, between February 1, 2022, and September 1, 2022. The methods used in the research included: the analysis of the specialized literature, the diagnosis questionnaire, and the mathematical-statistical method. The main conclusions of the study refer to the benefits of the handball game, its role in the morpho-functional development of the pupils, the level of motivation of the pupils to practice this game within the physical education and sports lessons, as well as outside the hours, within the handball high school team

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