Documenting the Constraints and Its Allied Factors in Agar (Aquilaria malaccensis Roxb.) Tree Cultivation at Farm Level: A Case Study in Bangladesh

The study was conducted to investigate the socio-economic characteristics of the agar farmers, the extent of constraints in agar wood cultivation; and the factors allied with constraints in agar tree farming. Despite the enormous potential of agar (Aquilaria malaccensis Roxb.) production in Bangladesh, it has yet to gain traction due to socioeconomic, technical, and marketing challenges. The cultivation of agar trees is largely centered in the Sylhet region, where a large number of agar farmers engage. This research was carried out in Maulvibazar district's Barlekha upazila (sub-district) to better understand and assess the restrictions and factors that affect agar tree cultivation. A survey was conducted with 120 households during September 2018 to March 2019. Descriptive statistics, rank order, coefficient of correlation, and multiple linear regression were used to examine the data. Out of 12 constraints, the most significant barrier was a lack of funds to engage in agar farming (2.81), which was followed by a lack of technical guidance (2.71). The lack of labor was the least important constraint faced by the farmers (1.43). It was revealed that education, household size, farm size, number of trees per farmer, annual income, experience in agar farming, agar wood cultivation under trees and knowledge of agar cultivation of the farmers were shown to be realized to agar plantation constraints. However, education, farm size, annual revenue, and agar growing experience were identified as major drivers of the degree of agar farming constraints. The study identified various policymakers' potential to address the influencing variables (education, farm size, annual revenue, and agar farming experience) in establishing agar farming. Furthermore, finance facilities, adequate agar farming instruction, and forest department introspection could all help to reduce agar farming obstacles.

Epidemic Dynamics of a Fractional-Order SIS Infectious Network Model

Outbreak and large-scale of the infectious diseases have caused enormous economic losses to all countries in the world. Constructing a network model which could reflect the transmission dynamics of the epidemics and investigating their transmission laws have a significant meaning in the precaution and control of the epidemics. In this article, a fractional-order SIS epidemic network model is proposed. First, an expression of the basic reproduction number is deduced. Second, applying the Lyapunov function, the stability of the equilibrium points about the infectious model is analyzed in detail. Finally, an example is present to verify the theoretical analysis. Furthermore, on account of the fractional-order coefficient, its influence on the transmission dynamics is also exhibited.

Optimized Factor Approximants and Critical Index

Based on expansions with only two coefficients and known critical points, we consider a minimal model of critical phenomena. The method of analysis is both based on and inspired with the symmetry properties of functional self-similarity relation between the consecutive functional approximations. Factor approximants are applied together with various natural optimization conditions of non-perturbative nature. The role of control parameter is played by the critical index by itself. The minimal derivative condition imposed on critical amplitude appears to bring the most reasonable, uniquely defined results. The minimal difference condition also imposed on amplitudes produces upper and lower bound on the critical index. While one of the bounds is close to the result from the minimal difference condition, the second bound is determined by the non-optimized factor approximant. One would expect that for the minimal derivative condition to work well, the bounds determined by the minimal difference condition should be not too wide. In this sense the technique of optimization presented above is self-consistent, since it automatically supplies the solution and the bounds. In the case of effective viscosity of passive suspensions the bounds could be found that are too wide to make any sense from either of the solutions. Other optimization conditions imposed on the factor approximants, lead to better estimates for the critical index for the effective viscosity. The optimization is based on equating two explicit expressions following from two different definitions of the critical index, while optimization parameter is introduced as the trial third-order coefficient in the expansion.

On asymptotic expansions for the fractional infinity Laplacian

We propose two asymptotic expansions of two interrelated integral-type averages, in the context of the fractional ∞-Laplacian Δ ∞ s for s ∈ ( 1 2 , 1 ). This operator has been introduced and first studied in (Comm. Pure Appl. Math. 65 (2012) 337–380). Our expansions are parametrised by the radius of the removed singularity ε, and allow for the identification of Δ ∞ s ϕ ( x ) as the ε 2 s -order coefficient of the deviation of the ε-average from the value ϕ ( x ), in the limit ε → 0 +. The averages are well posed for functions ϕ that are only Borel regular and bounded.

Práticas agrícolas sustentáveis e variáveis socioeconômicas

Considerando-se os distintos problemas ambientais, especialmente os relacionados a práticas agrícolas predatórias, que provocam a degradação dos recursos naturais, propõe-se, neste estudo, a análise da associação de práticas agrícolas sustentáveis com as variáveis socioeconômicas: gênero, idade, escolaridade, estado civil e renda, de um grupo de produtores rurais dos municípios Crato, Juazeiro do Norte e Barbalha, na Região Metropolitana do Cariri, Estado do Ceará, no Nordeste do Brasil. Inicialmente, foram realizadas entrevistas a sessenta produtores rurais, com a finalidade de identificar as variáveis socioeconômicas acima descritas. A partir das entrevistas, foi, ainda, possível evidenciar se há, por parte dos produtores, a adoção de práticas agrícolas sustentáveis, representada pelo índice de sustentabilidade ambiental de cada propriedade pesquisada. Por fim, realizou-se tratamento estatístico das variáveis, por meio da estimação do coeficiente de Spearman (Spearman rank-order coefficient), através do programa Data Analysis and Statical Software - Stata, versão 11. A pesquisa revelou que, para a amostra consultada, as variáveis Gênero, Idade, Escolaridade e Renda não foram estatisticamente significativas para confirmar associação com o índice de sustentabilidade ambiental das propriedades; enquanto a variável 'Estado civil' demonstrou uma fraca correlação, sendo possível afirmar que os produtores(as) casados(as) ou em união estável estão mais associados(as) à adoção de práticas de manejo ambientalmente adequadas, resultando em um maior índice de sustentabilidade da propriedade.