Effects of climate change on the distribution of endemic <Emphasis Type="Italic">Ferula xylorhachis</Emphasis> Rech.f. (Apiaceae: Scandiceae) in Iran: Predictions from ecological niche models

Ferula xylorhachis Rech.f. is an endemic plant species belonging to the Apiaceae family and distributed in northeastern Iran. In the present study, we attempted to determine the factors with the greatest effects on the distribution of this species and to determine suitable regions for it based on current and future conditions. The Maximum Entropy method was used in the present study and the results indicated that the Mean Temperature of Wettest Quarter (48.2%), Precipitation of Wettest Quarter (49.1%), and Precipitation of Wettest Month (61.4%) are the most important factors in the current and in two future periods (2040 and 2070). The models suggest that suitable regions for the presence of this species will change over time and that the species will encounter limitations through changes such as moisture reduction. According to the A1B scenario, increases in greenhouse gases such as CO₂ and CH₄ will have direct effects on future precipitation and temperature and these factors will be important in determining species dispersion. Evaluation of important habitat factors using normal ecological methods will help in developing the best conservation programs in the future. Introducing species to new regions will help to protect them from the extinction risk caused by climate change.     

Sustainable multi-trip periodic redesign-routing model for municipal solid waste collection network: the case study of Tehran

Environmental Science and Pollution Research - Daily transportation of wastes due to its environmental, financial, and social aspects has been considered a challenging issue in developing...     

Investigation of land use changes in rural areas using MCDM and CA-Markov chain and their effects on water quality and soil fertility in south of Iran

The purpose of the study is to predict drought changes in Dariun, Fars Province, and their impact on water and soil quality. To prepare drought, water, and soil quality zoning maps, Landsat satellite images and the kriging method were used. The fuzzy maps and weights for each parameter were then determined using fuzzy and analytic hierarchy process (AHP) methods. Additionally, cellular automata (CA)-Markov chains were used in order to predict the impact of drought changes on water and soil quality. Using the fuzzy-AHP method, water quality and soil fertility in 2020 were lower compared to previous years, mainly because of land use changes that increased pollution. Based on results of the Markov and CA-Markov chains, approximately 31% of the region will have very poor levels of soil fertility and water quality in 2050. Further, based on remote sensing indicators, it is determined that about 25% of the region will be at high risk of drought in 2050. Thus, if adequate management of the region is not done, the possibility of living in these areas may diminish in the coming years due to drought and deteriorated water and soil quality.

     

Evaluation of bio-aerosols type,density, and modeling of dispersion in inside and outside of different wards of educational hospital

Environmental Science and Pollution Research - Exposure to bioaerosols in the air of hospitals is associated with a wide range of adverse health effects due to the presence of airborne...     

Spatio-temporal assessment of land use dynamics and urbanization: linking with environmental aspects and DPSIR framework approach

Environmental Science and Pollution Research - Urbanization is the main force of the global environmental as well as land use land cover changes (LULC). Urbanization is caused by prompt increase in...     

Colloid transport in unsaturated porous media: the role of water content and ionic strength on particle straining

Packed column and mathematical modeling studies were conducted to explore the influence of water saturation, pore-water ionic strength, and grain size on the transport of latex microspheres (1.1 microm) in porous media. Experiments were carried out under chemically unfavorable conditions for colloid attachment to both solid-water interfaces (SWI) and air-water interfaces (AWI) using negatively charged and hydrophilic colloids and modifying the solution chemistry with a bicarbonate buffer to pH 10. Interaction energy calculations and complementary batch experiments were conducted and demonstrated that partitioning of colloids to the SWI and AWI was insignificant across the range of the ionic strengths considered. The breakthrough curve and final deposition profile were measured in each experiment indicating colloid retention was highly dependent on the suspension ionic strength, water content, and sand grain size. In contrast to conventional filtration theory, most colloids were found deposited close to the column inlet, and hyper-exponential deposition profiles were observed. A mathematical model, accounting for time- and depth-dependent straining, produced a reasonably good fit for both the breakthrough curves and final deposition profiles. Experimental and modeling results suggest that straining--the retention of colloids in low velocity regions of porous media such as grain junctions--was the primary mechanism of colloid retention under both saturated and unsaturated conditions. The extent of stagnant regions of flow within the pore structure is enhanced with decreasing water content, leading to a greater amount of retention. Ionic strength also contributes to straining, because the number of colloids that are held in the secondary energy minimum increases with ionic strength. These weakly associated colloids are prone to be translated to stagnation regions formed at grain-grain junctions, the solid-water-air triple point, and dead-end pores and then becoming trapped.     

Spatial and temporal analysis of ground level ozone and nitrogen dioxide concentration across the twin cities of Pakistan

The analyses presented in this paper include the concentration levels of NO₂ and O₃ measured during 2 successive years in twin cities (Rawalpindi and Islamabad) of Pakistan from November 2009 to March 2011. NO₂ was determined using the passive sampling method, while ozone was determined by Model 400E ozone analyzer. The average NO₂ and O₃ concentration in twin cities of Pakistan was found to be 44?±?6 and 18.2?±?1.24 ppb, respectively. Results indicate that the concentration of NO₂ and O₃ show seasonal variations. Results also depict that NO₂ and O₃ concentration levels are high in areas of intense traffic flow and congestion. Rawalpindi has more elevated levels of NO₂ and O₃ as compared to the Islamabad due to the narrow roads, enclosing architecture of road network and congestion. Climatic variables also influenced the NO₂ and O₃ concentration, i.e., temperature is positively related with O₃, while negatively related with NO₂, relative humidity is directly related with NO₂ and inversely related with O₃, whereas rainfall show negative association with both NO₂ and O₃ concentration. Comparing the results with WHO standards reveals that NO₂ concentration levels at all the sampling points are above the permissible limit, while ozone concentration is still lower than the WHO standards. Thus, there is a need to take appropriate steps to control these continuously increasing levels of NO₂ and O₃ before they become a serious hazard for the environment and people living in those areas.     

Effect of Thermo-Mechanical Degradation of Polypropylene on Hygroscopic Characteristics of Wood Flour-Polypropylene Composites

In this research, the influence of thermo-mechanical degradation of polypropylene (PP) on water absorption and thickness swelling of beech wood flour–PP composites were studied. For this purpose, a virgin PP was thermo-mechanically degraded by two times extrusion under controlled conditions. The results showed that the melt flow index, water absorption and thickness swelling of PP significantly increase by extrusion and re-extrusion. The virgin PP and degraded polypropylene were compounded with wood flour (at 60% by weight wood flour loading) in a counter-rotating twin-screw extruder in presence or absence of MAPP to produce wood flour–PP composites. From the results, the composites containing recycled PP exhibited higher water absorption and thickness swelling. The use of MAPP decreased water absorption and thickness swelling in composites made of virgin or recycled PP.