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•Sludge and manure present high range and level of antibiotics.•Composting is a solution to partially remove some antibiotics.•The transformation pathways are barely known.•The fate ...of antibiotic resistance genes during composting still remains inconsistent.•Authorized levels of antibiotics in sludge, manure and compost should be considered.
Wastewater treatment plant effluent, sludge and manure are the main sources of contamination by antibiotics in the whole environment compartments (soil, sediment, surface and underground water). One of the major consequences of the antibiotics discharge into the environment could be the prevalence of a bacterial resistance to antibiotic. In this review, four groups of antibiotics (Tetracyclines, Fluoroquinolones, Macrolides and Sulfonamides) were focused for the background on their wide spread occurrence in sludge and manure and for their effects on several target and non-target species. The antibiotics concentrations range between 1 and 136,000 μg kg−1 of dry matter in sludge and manure, representing a potential risk for the human health and the environment. Composting of sludge or manure is a well-known and used organic matter stabilization technology, which could be effective in reducing the antibiotics levels as well as the antibiotic resistance genes. During sludge or manure composting, the antibiotics removals range between 17–100%. The deduced calculated half-lives range between 1–105 days for most of the studied antibiotics. Nevertheless, these removals are often based on the measurement of concentration without considering the matter removal (lack of matter balance) and very few studies are emphasized on the removal mechanisms (biotic/abiotic, bound residues formation) and the potential presence of more or less hazardous transformation products.
The results from the few studies on the fate of the antibiotic resistance genes during sludge or manure composting are still inconsistent showing either decrease or increase of their concentration in the final product.
Whether for antibiotic or antibiotic resistance genes, additional researches are needed, gathering chemical, microbiological and toxicological data to better understand the implied removal mechanisms (chemical, physical and biological), the interactions between both components and the environmental matrices (organic, inorganic bearing phases) and how composting process could be optimized to reduce the discharge of antibiotics and antibiotic resistance genes into the environment.
The magnetization switching process in four-fold anisotropy materials is characterized by an intermediate state (IS) due to the interplay between magnetic anisotropy and spin-transfer torque (STT). ...Practically, the presence of an IS can impede the switching process in a single-step, causing switching errors during data storage. Here, we investigate the STT-induced magnetization switching in the MTJ device based on half-metallic full-Heusler Co2FeAl0.5Si0.5 (CFAS) alloy with four-fold anisotropy in the presence of voltage-controlled magnetic anisotropy (VCMA) using micromagnetic simulation. Our results demonstrate that VCMA-assisted STT can effectively tune the magnetic states during the switching by adjusting the VCMA effect at appropriate intervals and strengths. As a result, the magnetization can overcome the limitations posed by the IS in the CFAS alloy, leading to single-step switching modes for low spin current density. Additionally, we revealed that pulsed voltage-assisted STT results in shorter switching times compared to conventional switching in four-fold anisotropy materials.
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•Intermediate state hampers magnetization switching, causing errors in data storage.•VCMA effectively tunes magnetic states during STT-induced switching in CFAS alloy.•VCMA and STT enable single-step switching modes with low spin current density.•Pulsed voltage-assisted STT enables faster switching in anisotropic materials.
The importance of phosphorus in the regulation of plant growth function is well studied. However, the role of the inorganic phosphate (Pi) molecule in the mitigation of abiotic stresses such as ...drought, salinity, heavy metal, heat, and acid stresses are poorly understood. We revisited peer-reviewed articles on plant growth characteristics that are phosphorus (P)-dependently regulated under the sufficient-P and low/no-P starvation alone or either combined with one of the mentioned stress. We found that the photosynthesis rate and stomatal conductance decreased under Pi-starved conditions. The total chlorophyll contents were increased in the P-deficient plants, owing to the lack of Pi molecules to sustain the photosynthesis functioning, particularly, the Rubisco and fructose-1,6-bisphosphatase function. The dry biomass of shoots, roots, and P concentrations were significantly reduced under Pi starvation with marketable effects in the cereal than in the legumes. To mitigate P stress, plants activate alternative regulatory pathways, the Pi-dependent glycolysis, and mitochondrial respiration in the cytoplasm. Plants grown under well-Pi supplementation of drought stress exhibited higher dry biomass of shoots than the no-P treated ones. The Pi supply to plants grown under heavy metals stress reduced the metal concentrations in the leaves for the cadmium (Cd) and lead (Pb), but could not prevent them from absorbing heavy metals from soils. To detoxify from heavy metal stress, plants enhance the catalase and ascorbate peroxidase activity that prevents lipid peroxidation in the leaves. The
HvPIP
and
PHO1
genes were over-expressed under both Pi starvation alone and Pi plus drought, or Pi plus salinity stress combination, implying their key roles to mediate the stress mitigations. Agronomy Pi-based interventions to increase Pi at the on-farm levels were discussed. Revisiting the roles of P in growth and its better management in agricultural lands or where P is supplemented as fertilizer could help the plants to survive under abiotic stresses.
Olive mill wastewater sludge (OMWS) is a by-product of the olive extraction process that is attracting substantial attention due to its extremely hazardous effects on aquatic and terrestrial ...ecosystems. OMWS is a product of the common disposal method of olive oil mill wastewater (OMWW) that accumulates in evaporation ponds. It is estimated that approximately 10 × 106 m3 of OMWS is generated worldwide each year. OMWS is characterized by its significantly variable physicochemical properties and organic pollutant constituents, such as phenols and lipids, which are dependent upon the environmental features of the receiving ponds. Nonetheless, many related studies have recognized the biofertilizer potential of this sludge owing to its high mineral nutrient and organic matter load. OMWS exhibits promising valorization potential in several fields, including agriculture and energy production. Compared to those of OMWW, studies of OMWS are still lacking concerning its composition and characteristics, which are necessary for the future implementation of efficient valorization strategies. The main purpose of this review paper is to fill the gap that exists in the literature by providing a critical analysis of the available data on OMWS production, distribution, characteristics, and properties. Additionally, this work sheds light on important factors affecting OMWS properties, including the variability of the indigenous microbial communities regarding bioremediation. Finally, this review addresses the current and future valorization routes, from detoxification to the development of promising applications in agriculture, energy, and the environment, which could have significant socioeconomic implications for low-income Mediterranean countries.
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•Olive mill wastewater sludge is characterized by a very high pollutant load.•Olive mill wastewater sludge secondary treatment negatively impacts the indigenous microflora.•Composting is the most suitable process for olive mill wastewater sludge treatment.•The nutritional content of olive mill wastewater sludge has great potential in agriculture.
Leishmaniasis is endemic in Morocco where both cutaneous and visceral forms coexist. To date, anthroponotic cutaneous leishmaniasis (ACL) determinants remain poorly investigated in Morocco. However, ...the disease risk factors identification is vital to determine the specific preventive process. In this aim, a case-control study was conducted in the main active ACL foci in central Morocco. Epidemiological data were extracted from bulletins, registers and annual reports of the regional direction of Health offices. The socioeconomic and environmental data were collected from epidemiological surveys, completed by a questionnaire intended for accessible positive population and control people selected from the cases’ entourage. The study included 258 cases and 395 controls. Our results showed that many socioeconomic factors were associated with ACL in Morocco such as the rural habitation (OR = 4.163; 95% CI: 2.91–5.96), movement to endemic area (OR = 4.53; 95% CI: 3.03–6.77), provenance from leishmaniasis foci (in Essaouira focus OR = 5.34; 95% CI: 1.19–24.03) and poverty. In addition, environmental factors like proximity of vegetation (OR = 2.45; 95% CI: 1.14–5.25), poor domestic hygiene, particularly the absence of sewage system/waste management (OR = 1.63; 95% CI: 1.35–1.96), and presence of animals (OR = 2.67; 95% CI: 1.14–5.25) increase the risk of ACL in Morocco. Except for Matrimonial status (married people, OR = 4.11; 95% CI: 1.80–9.41), there is however no significant association of the disease with the other socio-demographic factors in the study area (p>0.05). These several risk factors must be taken in consideration to prevent this disease through multidisciplinary collaboration and community participation.
Rainfall regimes are expected to shift on a regional scale as the water cycle intensifies in a warmer climate, resulting in greater extremes in dry versus wet conditions. Such changes are having a ...strong impact on the agro-physiological functioning of plants that scale up to influence interactions between plants and microorganisms and hence ecosystems. In (semi)-arid ecosystems, the date palm (
Phoenix dactylifera
L.) -an irreplaceable tree- plays important socio-economic roles. In the current study, we implemeted an adapted management program to improve date palm development and its tolerance to water deficit by using single or multiple combinations of exotic and native arbuscular mycorrhizal fungi (AMF1 and AMF2 respectively), and/or selected consortia of plant growth-promoting rhizobacteria (PGPR: B1 and B2), and/or composts from grasses and green waste (C1 and C2, respectively). We analyzed the potential for physiological functioning (photosynthesis, water status, osmolytes, mineral nutrition) to evolve in response to drought since this will be a key indicator of plant resilience in future environments. As result, under water deficit, the selected biofertilizers enhanced plant growth, leaf water potential, and electrical conductivity parameters. Further, the dual-inoculation of AMF/PGPR amended with composts alone or in combination boosted the biomass under water deficit conditions to a greater extent than in non-inoculated and/or non-amended plants. Both single and dual biofertilizers improved physiological parameters by elevating stomatal conductance, photosynthetic pigments (chlorophyll and carotenoids content), and photosynthetic efficiency. The dual inoculation and compost significantly enhanced, especially under drought stress, the concentrations of sugar and protein content, and antioxidant enzymes (polyphenoloxidase and peroxidase) activities as a defense strategy as compared with controls. Under water stress, we demonstrated that phosphorus was improved in the inoculated and amended plants alone or in combination in leaves (AMF2: 807%, AMF1+B2: 657%, AMF2+C1+B2: 500%, AMF2+C2: 478%, AMF1: 423%) and soil (AMF2: 397%, AMF1+B2: 322%, AMF2+C1+B2: 303%, AMF1: 190%, C1: 188%) in comparison with controls under severe water stress conditions. We summarize the extent to which the dual and multiple combinations of microorganisms can overcome challenges related to drought by enhancing plant physiological responses.
•Magnetization states under the spin-transfer effect are elucidated in a Co1.5Fe1.5Ge nanopillar alloy.•A comparative study has been accomplished by numerically solving the Landau-Lifshitz-Gilbert ...equation with the Spin-Transfer Torque contributions.•Single-step magnetization switching under weak spin-polarized currents is possible for well-adjusted dimensions.
In this work, the magnetization states under the spin-transfer switching effect are investigated in a nanopillar device composed of a half-metallic Heusler Co1.5Fe1.5Ge alloy with a four-fold in-plane magnetocrystalline anisotropy. A comparative study with a half-metallic Heusler alloy of Co2FeAl0.5Si0.5 and a typical material of Fe is realized by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation with the Spin-Transfer Torque (STT) contribution, using micromagnetic simulations. Our ultimate goal is to elucidate the origins of the intermediate state (IS) that occurs during magnetization switching by deeply examining the effects of magnetocrystalline anisotropy and shape anisotropy on the magnetization states through analyzing and comparing various switching processes. Our simulation results showed that the magnetization switching via a single-step under low current densities is possible at certain critical cross-sectional dimensions of the ellipse that are adjusted to increase the demagnetization field against the four-fold in-plane magnetocrystalline anisotropy. As well, we provided in this paper a set of appropriate geometric dimensions which allow the magnetization to reverse via a single-step by overcoming IS with minimal spin-polarized current densities.
For all living organisms, nitrogen is an essential element, while being the most limiting in ecosystems and for crop production. Despite the significant contribution of synthetic fertilizers, ...nitrogen requirements for food production increase from year to year, while the overuse of agrochemicals compromise soil health and agricultural sustainability. One alternative to overcome this problem is biological nitrogen fixation (BNF). Indeed, more than 60% of the fixed N on Earth results from BNF. Therefore, optimizing BNF in agriculture is more and more urgent to help meet the demand of the food production needs for the growing world population. This optimization will require a good knowledge of the diversity of nitrogen-fixing microorganisms, the mechanisms of fixation, and the selection and formulation of efficient N-fixing microorganisms as biofertilizers. Good understanding of BNF process may allow the transfer of this ability to other non-fixing microorganisms or to non-leguminous plants with high added value. This minireview covers a brief history on BNF, cycle and mechanisms of nitrogen fixation, biofertilizers market value, and use of biofertilizers in agriculture. The minireview focuses particularly on some of the most effective microbial products marketed to date, their efficiency, and success-limiting in agriculture. It also highlights opportunities and difficulties of transferring nitrogen fixation capacity in cereals.
The hysteresis loops and compensation behaviors of a ferrimagnetic mixed system, consisting of two sublattices (A and B) with different spins (S
A
= 1 and S
B
= ½) and described by Heisenberg ...Hamiltonian on a cubic lattice, are investigated by using the pair approximation method. We have discussed the dependence of the compensation temperature on the D- crystal field interaction and J-exchange anisotropy. The influence of the longitudinal magnetic field and the magnetic hysteresis loops are also carried out. It is found that the model of mixed spin exhibits the possibility of two compensation points for several given sets of parameters. The model yields also second-order and first-order phase transitions, in addition to tricritical points. The reentrant phenomena can occur in some narrow ranges of D /|J
z
| and J
xy
/|J
z
|.
We have also observed the existence of triple hysteresis loop behaviors under the effects of special intrinsic parameters.
Abstract
In this work, an ultrafast nucleation of an isolated anti-ferromagnetic (AFM) skyrmion was reported in an AFM layer with DMi strengths of 0.47
$$-$$
-
0.32
$$\mathrm{mJ}/{\mathrm{m}}^{2}$$
...mJ
/
m
2
using spin-transfer torque by locally injecting pure spin currents into magnetic tracks. Besides, we revealed the key advantages of AFM skyrmion-based racetrack memories by comparing the motion of AFM and FM skyrmions driven by spin–orbit torques (SOTs) for different skyrmion sizes along racetrack memories with various notch sizes. Our results indicate that for AFM skyrmion, the skyrmion Hall effect does not exist during the skyrmion motion, therefore at small skyrmion sizes, we succeeded to overcome the repulsive forces developed in the notch area for low and large SOTs. The obtained findings were carefully analyzed by computing the variation of energy barriers associated with the notch for different skyrmion sizes using minimum energy path (MEP) calculations. We showed that the larger the skyrmion size, the harder it is to shrink the skyrmion in the notch which produces a high energy barrier (E
b
) for large skyrmion sizes. Moreover, as the notch size increases, the skyrmion size shrinks further, and hence E
b
increases proportionally. Nevertheless, we proved that AFM skyrmions are more efficient and flexible than FM skyrmions against boundary forces.
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