Vol. 11, No. 4 (2023): Regular Issue

The disastrous impact of climate change is already being felt around the globe. Climate change is affected by increasing discharges of greenhouse gases. Pakistan's metropolitan air pollution is among the utmost severe in the world and it bases main reparations on economic activities and affects human health. This study has been designed for the analysis of ambient air quality in different Karachi areas. The surveys have been done based on seasonal variation i.e., pre and post-monsoon from four industrial zones viz. S.I.T.E area, North Karachi industrial area, Korangi industrial area, and Landhi industrial area in the year 2019. These zones are com-prised of the industrial, residential, and commercial sectors, so heavy traffic and dense populations affect these zones. In this study, HAZ-SCANNER (HIM-6000) apparatus was used for data collection of Ambient air pollutants like nitrogen oxides (NOx), carbon monoxide (CO), and sulphur dioxide (SO$_{2}$), particulate matters (TSPM, PM$_{10}$, and PM$_{2.5}$). For spatial-temporal analysis of ambient air quality GIS interpolation (IDW) technique has been used. It is observed that in post-monsoon, the intensity of particulate matters (TSPM, PM$_{10}$ & PM$_{2.5}$), CO, and NO$_2$ values in sampling sites are less to moderate than the values of pre-monsoon due to the seasonal monsoon effects. While North Karachi is at the least risk because of having a small number of scale industries pre-sent. The PM$_{10}$ & PM$_{2.5}$ levels average about 2-3 fold greater than the SEPA standards. High levels of ambient air pollutants cause severe health problems and chronic diseases on human health. Therefore, the implementation of rules and regulations regarding ambient air pollutants should be more active.

In this paper, a modified ratio-dependent Bazykin prey-predator model with prey refuge and constant harvesting of both species has been considered. The significant mathematical attributes of the proposed model are studied with the assistance of equilibria, local stability analysis, and bifurcation theory. The model displays a complex dynamics within the prey-predator plane. The existence and stability of possible equilibria are examined. The existence of Hopf bifurcation is obtained by analyzing the associated characteristic equation. The direction of the Hopf-bifurcating periodic solution and its stability are determined by calculating the first Lyapunov coefficient. Also, it has been proven that the proposed model exhibits Bogdanov-Takens bifurcation of codimension two for an appropriate choice of bifurcation parameters and calculating the conventional form. Furthermore, some numerical examples are provided to illustrate the theoretical finding. Lastly, discuss their ecological interpretations.

To analyze the coherent structures and the partitioning quality of the atmosphere, the network algorithm is introduced and applied to double gyre flow and Arctic stratospheric flow. By partitioning the network, each part consisting of regions with similar dynamic behaviors, including mass transport and mixing, can be identified from Lagrangian frame. First, a directed network is considered by using the trajectories of sampled particles, and Lagrangian flow network (LFN) is established by capturing the mass exchanges between pairs of grid points in the streamflow. Then, the Infomap method is used to detect well-connected regions. In particular, both coherence and mixing metrics can be served as indicators of transport, and therefore the spatial connectivity can be quantified. Further, the proposed efficient method and LFN are implemented successfully in the practical geophysical flow, and the dynamic behaviors of the flow in Arctic are analyzed in detail. By the example, the advantages of the ensemble solutions are evaluated as analyzing the structures of the flow field, and the extent of the impact on the community is assessed in the selection of the open domain. Also, the persistence of coherent structures of streamflow is verified over years. As the conclusion, it is shown that LFN is a novel and promising quantitative analysis method. The results obtained could gain the key understanding on dynamic behaviors in streamflow and the development of complex networks in the research of atmospheric spatial connectivity.

In this paper, the large eddy simulation (LES) method is applied to gas diffusion process in open space under wind effect. Firstly, the governing equations of gas diffusion employed in LES are introduced, and the corresponding solution procedure is discussed. Subsequently, using LES with DSM subgrid-scale model, the diffusion process of the methane discharging from a chimney under wind effect is simulated, and the lateral and vertical distribution patterns of methane concentration in the wake of the chimney are compared with the experimental results, to examine the accuracy and stability of LES in simulating the diffusion process of light gas in open space. Finally, using the full-scale experimental results concerning diffusion of the mixture gas of nitrogen and Freon-12, the accuracy of LES in simulating heavy gas diffusion is examined, and the advantage of LES over Reynolds-averaged Navier-Stokes (RANS) method in computing the unsteady gas diffusion process is examined. For both cases considering light gas and heavy gas, the numerical results from LES show very good agreement with the experimental results, indicating its potential in simulating the gas discharging or leakage process in various industrial applications.

The purpose of the study is to establish the impact of corporate governance, financial performance, intellectual capital and size of the enterprise on the quality of information disclosure in integrated reporting. The study used data from 30 large enterprises in various sectors of the economy of Ukraine, selected from annual financial statements, management reports and integrated reporting for 2018 and 2019, which are published and posted on their official websites. The statistical method of partial least square (PLS) data analysis in the computer program SmartPLS 3 was used to process the information. The results of the study showed that corporate governance, financial indicators, intellectual capital have a significant positive impact on integrated reporting, which did not confirm any dependence. The study conducted a comparative analysis of domestic and international research experience on the subject, identified issues and identified prospects for further development related to integrated reporting.

The present study deals with the study of the dynamics of an eco-epidemiological prey-predator mathematical system. The model that is proposed is an eco-epidemiological system of prey-predator association in consideration of discrete time delay where the prey population suffers from a disease which is modelled by the Susceptible-Infected (SI) epidemic scheme. We have assumed that the predator devours the vulnerable prey along with the diseased prey population in accordance with the modified Holling type II functional response. Harvesting of susceptible prey and predator have been considered and their effect has been analyzed also. To avoid the extinction of the prey population, refuge of prey is considered and its effect is observed on the stability of the system. Numerical simulation of the models reveals that the dynamical system undergoes Hopf-bifurcation due to the encounter rate, presence of refuge population and infection rate. Ecologically, the study discloses that harvesting, refugia and the rate of infection can be effectively used as a modulating parameter and may explain the reason behind the coexistence of prey-predator species and can remarkably affect the equilibrium of the dynamical system.

In the mid 2000's the Brazilian Government introduced a new environmental policy to reduce deforestation in the ``Plan for Prevention and Control of Legal Amazon Deforestation'', (PPCDAM). With 14 years of track record, heavily relying on technological innovation, the policy is nowadays considered a major example of success in the overall war waged against the deforestation of tropical rainforests. In this paper we quantify this success. The results suggest that the policy not only had a direct effect of reducing deforestation, but also rendered deforestation less sensitive to fluctuations in the Amazon commodity production, which can be considered our academic contribution to this paper. We also perform a counterfactual exercise, estimating the levels of deforestation that would have been registered, had the policy not existed. We estimate that the plan saved a total of 196 thousand square kilometers of forest between 2005 and 2015, corresponding to almost twice the total amount of deforestation observed during this period, and 4.9% of the entire Brazilian Amazon Forest.