79 research outputs found

    Gravitational Waves from Preheating in Gauss-Bonnet Inflation

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    We study gravitational wave production in an expanding Universe during the first stages following inflation, and investigate the consequences of the Gauss-Bonnet term on the inflationary parameters for a power-law inflation model with a GB coupling term. Moreover, we perform the analyses on the preheating parameters involving the number of e-folds NpreN_{pre}, and the temperature of thermalization Tth,T_{th}, and show that it's sensitive to the parameters nn, and γ\gamma, the parameter γ\gamma is proposed to connect the density energy at the end of inflation to the preheating energy density. We set a correlation of gravitational wave energy density spectrum with the spectral index nsn_{s} detected by the cosmic microwave background experiments.. The density spectrum Ωgw\Omega_{gw} shows good consistency with observation for γ=103\gamma = 10^{3} and 10610^{6}. Our findings suggest that the generation of gravitational waves (GWs) during preheating can satisfy the constraints from Planck's data

    Dark matter via Baryogenesis: Affleck-Dine Mechanism in the Minimal Supersymmetric Standard Model

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    We conducted an investigation into Affleck-Dine baryogenesis within the context of D-term inflation, specifically focusing on its relationship with a recent reheating formalism. It was found that by considering a specific reheating temperature, the observed baryon asymmetry can be accounted through Affleck-Dine baryogenesis. Additionally, the majority of gravitinos are inferred to be generated from the decay of the next-to-lightest supersymmetric particle, with Q-balls potentially serving as a source of gravitinos via NSP decay. The temperature at which decay occurs depends on the charge of the Q-balls, which is determined by the fragmentation of the Affleck-Dine condensate. Remarkably, the gravitino mass required for dark matter aligns naturally with the theoretical gravitino mass.Comment: 11 pages, 4 figure

    Plant growth promoting activities of Pseudomonas sp. and Enterobacter sp. isolated from the rhizosphere of Vachellia gummifera in Morocco

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    The Moroccan endemic Vachellia gummifera grows wild under extreme desert conditions. This plant could be used as an alternative fodder for goats, and camels, in order to protect the Argan forests against overgrazing in Central and Southwestern Moroccan semiarid areas. With the aim to improve the V. gummifera population's density in semiarid areas, we proposed its inoculation with performing plant growth-promoting bacteria. Hence, 500 bacteria were isolated from the plant rhizosphere. From these, 291 isolates were retained for plant growth-promoting (PGP) activities assessment. A total of 44 isolates showed the best phosphates solubilization potential, as well as siderophore and auxin production. The combination of REP-PCR (repetitive extragenic palindromic-polymerase chain reaction) fingerprinting, PGP activities, and phenotypic properties, allowed the selection of three strains for the inoculation experiments. The three selected strains' 16S rRNA sequencing showed that they are members of the Enterobacter and Pseudomonas genera. The inoculation with three strains had diverse effects on V. gummifera growth parameters. All single and combined inoculations improved the plant shoot weight by more than 200%, and the root length by up to 139%, while some combinations further improved protein and chlorophyll content, thereby improving the plant's forage value. The three selected strains constitute an effective inoculum for use in the arid and semiarid zones of southern Morocco.The authors want to thank all the persons who contributed to the achievement of this work. This work was funded by the Hassan II Academy of Science and Technology (AH2ST), in Morocco. B.M. received a grant from the AH2ST. She received also the excellency fellowship Khadija Baddouri in life sciences, from the Horizons foundation, Franc

    Different species of Bradyrhizobium from symbiovars genistearum and retamae nodulate the endemic Retama dasycarpa in the High Atlas Mountains

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    Retama dasycarpa is an endemic Retama species native to the cold semi-arid bioclimates of the High Atlas Mountains in Morocco. In this work, we analyzed the diversity of the microsymbionts nodulating this plant and their different phenotypic and symbiotic characteristics. Phylogenetic analysis of the 16S rRNA gene revealed that the tested isolates clustered in the Bradyrhizobium genus. Multilocus sequence analyses of four housekeeping genes (recA, gyrB, glnII and atpD) for 12 selected strains grouped them into four clusters close to B. lupini USDA 3051, B. frederickii CNPSo 3446, B. valentinum LmjM3 and B. retamae Ro19. The individual phylogenies of these core genes and the symbiotic genes nodC, nodA and nifH were congruent. These isolates showed a broad host range, being able to nodulate different legume hosts, such as R. sphaerocarpa, R. monosperma, Lupinus luteus, Cytisus grandiflorus and Chamaecytisus albidus, but not Phaseolus vulgaris or Glycine max. They all had a similar metabolic capacity, using the majority of the carbohydrates and amino acids tested as sole sources of carbon and nitrogen. Furthermore, out of the 12 selected strains, some displayed plant growth-promoting features, with six of them solubilizing phosphate and three of them producing siderophores. The present work provides, for the first time, a detailed description about the microsymbionts associated with the endemic legume R. dasycarpa.This work was supported by the Ministry of Higher Education and Innovation. Dr Mouad Lamrabet was granted a fellowship from the PPR2-BIOMIVER project. The authors want to thank all the people who contributed to this work

    False aneurysm of the radial artery: Unusual complication of both-bone forearm fracture in children: A case report

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    False aneurysm or pseudo aneurysm of an artery in close proximity to fractured bone is a well-recognized entity, and fewer various cases, involving different sites have been reported in the literature. We report new case of a Moroccan's patient who had 10-year-old boy presented with a right non displaced both-bone forearm fracture; the patient was placed in a long arm splint. After, six weeks, the cast was removed. And a pulsatile mass on the volar-radial aspect of the forearm was decouvred. The mass was non-tender and the patient had radial and ulnar pulse. An Ultrasound and brachial angiography showed a false aneurysm of distal radial and the radial artery was ligated

    Bacteria-inducing legume nodules involved in the improvement of plant growth, health and nutrition

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    Bacteria-inducing legume nodules are known as rhizobia and belong to the class Alphaproteobacteria and Betaproteobacteria. They promote the growth and nutrition of their respective legume hosts through atmospheric nitrogen fixation which takes place in the nodules induced in their roots or stems. In addition, rhizobia have other plant growth-promoting mechanisms, mainly solubilization of phosphate and production of indoleacetic acid, ACC deaminase and siderophores. Some of these mechanisms have been reported for strains of rhizobia which are also able to promote the growth of several nonlegumes, such as cereals, oilseeds and vegetables. Less studied are the mechanisms that have the rhizobia to promote the plant health; however, these bacteria are able to exert biocontrol of some phytopathogens and to induce the plant resistance. In this chapter, we revised the available data about the ability of the legume nodule-inducing bacteria for improving the plant growth, health and nutrition of both legumes and nonlegumes. These data showed that rhizobia meet all the requirements of sustainable agriculture to be used as bio-inoculants allowing the total or partial replacement of chemicals used for fertilization or protection of crops

    Numerical Analysis of the Passive Heating of Building integrated Phase Change Materials

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    peer reviewedIn order to explore numerically the capability of solid-liquid phase change material (PCM) for heating indoor applications, melting of phase change material (PCM) was studied. The roof of the enclosure is filled with PCM (Hydrate salts PCM with melting temperature, Tmelt = Tcomfort =22 °C) on which are inserted heat pipes coming from the solar collector (heat source). The oom vertical walls are adiabatic. The power transferred from solar collector by water is fully dissipated in a PCM that filled a slab. The advantage of using this heating strategy is that the PCMs are able to store a high amount of heat generated by the solar collector and the sun rising on the slab without acting the HVAC system. Numerical investigations, based on a dynamic simulation, were conducted in order to analyze the thermal performance of the proposed system. It was found that, due to the PCM layer, there are less temperature fluctuations and comfortable leaving conditions are satisfied. The use of the HVACs systems will be remarkably reduced during January in Casablanca Morocco

    Performance evaluation of latent heat TES system-case study:Dimensions improvements of annular fins exchanger

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    Thermal Energy Storage (TES) is an important challenge for the development and implementation of Concentrated Solar Power (CSP) plants. The heat can be stored in a sensible, thermochemical or latent form. Recently, the latent heat thermal energy storage (LHTES) kind has gained the most of research interest as it has the advantage of increasing the energy density of the current commercial TES systems through the use of a Phase Change Materials (PCM). However, the main limitation of PCMs technology is the low thermal conductivity, which affects the system performances and lead to significant energy losses. In this sense, a good container design can impact positively the system performances. For that sake, several designs have been proposed to overcome the decreasing heat transfer rate. For this purpose, this study propose many enhancements and improvements of the fins method based on the integration of PCM in an exchanger with annular fins. The main objective of this paper is to study the impact of finned exchangers on the total flow transferred and also on the height of these annular fins. Finally, the physical model describing the thermal behavior of the studied system is developed and simulated after 80 min of charging process.</p
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