查看更多>>摘要：The ability to accurately forecast the number of COVID-19 cases and future case trends would certainly assist governments and various organisations in strategising and preparing for the newly infected cases well in advance. Many predictions have failed to foresee future COVID-19 cases due to the lack of reliable data; however, such data are now widely available for predicting future trends in COVID-19 after more than one and a half years of the pandemic. Also, various countries are closely monitoring other countries that are experiencing a surge in COVID-19 cases in the expectation of similar scenarios, but this does not always produce correct results, as no research has identified specific correlations between different countries in terms of COVID-19 cases. During the past 18 months, many nations have watched countries whose COVID-19 cases have risen sharply, in anticipation of handling the situation themselves. However, this did not provide accurate results, as no research was conducted that compared countries to determine if their COVID-19 case trends were correlated. As official data on COVID-19 cases has become increasingly available, using the Pearson correlation technique to pinpoint the countries that should be closely monitored will help governments plan and prepare for the number of infections that are expected in the future at an early stage. In this study, a simple and real-time prediction of COVID-19 cases incorporating existing variables of coronavirus variants was used to explore the correlation among different European countries in terms of the number of COVID-19 cases officially recorded on a daily basis. Data from selected countries over the past 76 weeks were analysed using a Pearson correlation technique to determine if there were correlations between case trends and geographical position. The correlation coefficient (r) was employed for identifying whether the different countries in Europe were interrelated, with r > 0.85 indicating they were very strongly correlated, 0.85 > r > 0.8 indicating that they were strongly correlated, 0.8 > r > 0.7 indicating that they were moderately correlated, and r < 0.7 indicating that the examined countries were either weakly correlated or that a correlation did not exist. The results showed that although some neighbouring countries are strongly correlated, other countries that are not geographically close are also correlated. In addition, some countries on opposite sides of Europe (Belgium and Armenia) are also correlated. Other countries (France, Iceland, Israel, Kosovo, San Marino, Spain, Sweden and Turkey) were either weakly correlated or had no relationship at all.
查看更多>>摘要：The sintering and the mechanical properties of tricalcium phosphate-magnesium fluoride composites have been investigated. The rupture strengths of the samples were studied using the Brazilian test. This property increased with both the sintering temperature and magnesium fluoride addition. The maximum mechanical strength of the composites, 9 MPa, was reached at 1300 degrees C. The highest performance was obtained for the tricalcium phosphate containing 7.5 wt% MgF2. This amelioration of performance is due to the presence of a liquid phase between the tricalcium phosphate and magnesium fluoride and the formation of a new compound. In fact, the value of the rupture strength is close to that of enamel (8-12 MPa). X-ray diffraction analysis of the composites revealed the presence of magnesium phosphate and fluorapatite. The IR spectra showed that most bands are associated with the phosphate group of tricalcium phosphate. The microstructure of the composites shows a new needle form, which is probably related to the new phases.
查看更多>>摘要：This study focused on the development of low-cost membranes in flat and tubular configurations, which were prepared from mixtures of kaolin, feldspar, sand, and aluminum alloy 6063 as novel supports for membrane filtration. Flat configurations were produced by dry pressing, whereas tubular configurations were obtained by an extrusion method. A comparison was made between supports of the same composition obtained by pressing and by extrusion in terms of microstructure and properties. Results showed that the addition of metal to the porcelain matrix has a positive effect on the cermet properties. Moreover, the mechanical strength either increases or decreases gradually in the presence of aluminum alloy. On the other hand, the porosity, pore distribution and water permeability of the ceramic supports increase proportionally with the ratio of aluminum alloy to porcelain matrix for flat and tubular configurations.
查看更多>>摘要：The disposal and management of waste resulting from construction, renovation, and demolition activities is one of the thorny problems that are prevalent in urban and rural areas of many developed and emerging countries around the world. The protection of the environment and natural resources currently represent a major socio-economic issue for geo-environmental specialists. In Algeria, one of the main objectives of protecting the environment and the ecosystem is to efficiently and effectively recycle waste from the construction industry. The recovery of construction and demolition waste (C&D) is essential and constitutes a path towards sustainable development. From this perspective, our work aims to valorize concrete waste by using it to improve the behavior of compressible soil in the Bouhanak-Tlemcen region (in the northwest of Algeria). Experimental compressibility (oedometric) tests were carried out on soil incorporating 10%, 15%, and 20% concrete waste by dry weight of the natural sample. The results showed good compressible soil response, while the impact of waste concrete is reduced.
查看更多>>摘要：Landfill leachate (LFL) from a controlled discharge in Tunisia was found to be highly loaded with ammonia. This study investigated the feasibility of an air stripping process aiming to mitigate the inhibitory effect of ammonia. Optimization of this process, using an orthogonal central composite design, intended to reduce the ammonia concentration and also to fix it in a safe range for the subsequent anaerobic process. Optimization showed that, to remove 60% of ammonia, pH, air flow rate, and reaction time should be fixed at 10.8, 6 L min(-1), and 18 h, respectively. The air stripping process improved the anaerobic digestion (AD) of leachate in an upflow anaerobic fixed bed reactor. Chemical oxygen demand (COD) removal efficiency exceeded 80% at an organic loading rate (OLR) of 1.3 g COD L-1 day(-1). Analysis of the organic compounds monitored by gas chromatography coupled to mass spectrometry (GC-MS) showed that contaminants were efficiently removed after the anaerobic process. Cytotoxicity was significantly reduced subsequent to the air stripping and anaerobic process.
查看更多>>摘要：Several water contamination accidents have been reported in the Kebili, Nefta and Hassi Messaoud regions situated in the Saharan Platform. Two major ecological disasters in Jemna and Hassi Berkaoui, which are parts of the same region, were investigated and well documented. In this work, an evaluation of water contamination risks was conducted, taking into account the pore pressure profile. The objectives were firstly to identify the potential overpressure dangers, and then to propose adequate solutions or recommendations to reduce the accident risks. The formation pressure profile in the Berkine basin was characterized by calculation and modelling methods based on logging data and drilling parameters. The used software computed the pore pressure using the d-exponent and sonic Eaton's method. Also, accurate local formation pressure surveys were used to calibrate and validate the results achieved at different control points. As a result, five overpressure intervals in the Berkine basin were highlighted that affect the wellbore stability and cause a potential risk of reservoir fluid exchange. The overpressure intervals are hosted in evaporite series of the Late Cretaceous, Early Jurassic-Late Triassic and Devonian intervals. It was concluded that the environmentally sensitive water tables in the Berkine basin are the Complex Terminal hosted in Tertiary sands to Senonian carbonates and the Continental Intercalaire aquifer hosted in Barremian and Albian sandstones. Both water tables are widely used in Saharan oases, contain good-quality water resources and have different pressure amplitudes. Nevertheless, pore pressure studies confirm that these aquifers exhibit a risk of high contamination by oil exploration activities. Based on the resulting pressure profile and the actual wellbore weak points, the source of danger was identified and a new well architecture and exhaustive cement bond evaluation were recommended for sustainable water-table protection and wellbore integrity.
查看更多>>摘要：The Tozeur Saharan oases represent one of the most vulnerable systems at risk, as inefficient agricultural practices and groundwater overexploitation in these oases have resulted in environmental threats linked to water quality degradation. In this study, hydrochemical analyses were used to assess the groundwater quality and mineralization processes, appraise the suitability of the water for drinking and irrigation purposes, and evaluate its human health risk. It was demonstrated that the groundwater mineralization is mainly controlled by water-rock interaction processes, i.e., the dissolution of evaporates and cation exchange processes, the irrigation water return flow, and the intrusion of chott brines. Groundwater quality assessment based on the total hardness (TH), water quality index (WQI) and entropy water quality index (EWQI) showed poor water quality and very hard groundwater. However, the majority of the groundwater samples were suitable for irrigation in terms of the sodium absorption ratio (SAR), sodium percentage (Na%), permeability index (PI), potential salinity (PS), Kelley ratio (KR) and magnesium ratio (MR). Nitrate and fluoride were evaluated to estimate the noncarcinogenic health risk when groundwater is consumed by children and adults using the United States Environmental Protection Agency (USEPA) method. Fluoride concentration exceeded the permissible limit (1.5 mg/l). The total hazard index (THI) calculated for children and adults indicated that 100% and 31% of the samples, respectively, presented a health hazard (THI> 1). These values confirmed that children are more vulnerable through direct ingestion of drinking water than adults. Consequently, pressing measures must be taken to reduce the risks of contaminated groundwater on public health.
查看更多>>摘要：Food and water demand has risen in recent years as a result of global population growth, economic development, and dietary changes. These trends, combined with the continued use of groundwater resources, have resulted in significant aquifer depletion rates in every country. Antalya's current water resources are springs and underground waters on the travertine plateau. On the karstic travertine plateau, there are numerous natural water sources and water drilling wells for domestic and agricultural use. In addition to the licensed drillings, there are numerous unlicensed wells on the plateau. Unlicensed wells have the same impact as licensed wells. As a result of excessive well water withdrawal and unlimited consumption, there has been insufficient aquifer recharge, which has resulted in a reduction in groundwater reserves, leading to disputes and legal action between well owners. Within the scope of this study, the potential effects of excessive water withdrawal from selected boreholes and well interactions on the Antalya travertine plateau were evaluated using field observations, well tests, and geographic information system methods. It was calculated that the radius of action for the water wells to be drilled on the travertine plateau should be at least R = 107.48 m. This case study, carried out on the Antalya travertine plateau, is meant to serve as a model for legal disputes, relevant public institutions, municipalities, and scientific studies concerning excessive water withdrawal and well interactions.
查看更多>>摘要：The genus Streptomyces remains a major source of novel pharmaceutically relevant compounds with antimicrobial activity. A screening method was carried out using ten strains of the genus Streptomyces, isolated from Tunisian soil (Ain Drahem), against Candida albicans pathogenic yeast. The antifungal activity of volatile compounds (VOCs) of Streptomyces isolates was released with the double dish method and the separate compartments dish method. This screening allowed us to select strain S103, which showed the highest inhibition rate against Candida albicans up to 65%. This strain was identified as Streptomyces olivochromogenes on the basis of its morphological characteristics, and 16S rRNA gene sequence analysis. After 14 days of incubation, solid-phase microextraction followed by gas chromatography-mass spectrometry (SPME-GC-MS) identified 15 volatile organic compounds produced by this strain. Among these, the most abundant volatile substance was D-limonene, with 55.81% of total peaks. Bioassay with standard D-limonene showed that 200 mu l per plate completely inhibited C. albicans growth by fumigation. Hence, microbial VOCs may be a new therapeutic alternative to combat the high incidence of Candida infections.
Tello, Antri VarnavaPapamichael, IlianaZorpas, Antonis A.
9页
查看更多>>摘要：Since its accession to the European Union, Cyprus has retained a negative attitude towards the cultivation of genetically modified organisms (GMOs) in its territory. This study aims to explore the attitudes of key stakeholders (e.g., non-governmental organizations (NGOs) and politicians) and public opinion, which influence decision-making regarding the cultivation of GMOs. To achieve the main objectives of our research, semi-structured interviews were carried out with representatives of NGOs and politicians (n = 12), focusing on the grounds for their support of a ban on the cultivation of GMOs. Content analysis of qualitative findings was performed using Nvivo 12 Plus, while the investigation of the public opinion on GMO cultivation was carried out using a structured questionnaire (n = 442) . The SPSS 21.0 program was used to analyze the obtained data. The results show that biodiversity and ecosystems on an isolated island with a large percentage of its area protected under Natura 2000, land fragmentation, the promotion of organic farming as well as traditional agricultural varieties, and beekeeping are the key reasons for stakeholders to stand against the cultivation of genetically modified crops (GMC) in Cyprus. The political decision of the Republic of Cyprus to oppose the cultivation of genetically modified organisms in Cyprus is influenced by the perceptions of stakeholders and public opinion. Half of the participants from the public agreed that GMOs have to be banned, while one-quarter agreed that it is necessary to cultivate drought-resistant GMOs as a tool to face climate change challenges. A very small percentage (5.2%) stated that the cultivation of GMOs should be allowed, but only when they are intended for use as animal feed, and only 19.2% of the participants agreed that the cultivation of GMC will bring economic growth to Cyprus. Taking into consideration all the above, Cyprus could be excluded from the cultivation of GMOs according to Directive EU 412/2015, which gives Member States (MS) the possibility of prohibiting the cultivation of GMOs in their territory based on compelling grounds.
NSTL
Springer Nature