Rational factors, invariant foliations and algebraic disintegration of compact mixing Anosov flow of dimension 33

In this article, we develop a geometric framework to study the notion of semi-minimality for the generic type of a smooth autonomous differential equation $(X,v)$, based on the study of rational factors of $(X,v)$ and of algebraic foliations on $X$, invariant under the Lie-derivative of the vector field $v$. We then illustrate the effectiveness of these methods by showing that certain autonomous algebraic differential equation of order three defined over the field of real numbers --- more precisely, those associated to mixing, compact, Anosov flows of dimension three --- are generically disintegrated.Comment: The title of the article has been changed in order to reflect better its conten

Abelian reduction in differential-algebraic and bimeromorphic geometry

Several results on the birational geometry of algebraic vector fields in characteristic zero are obtained. In particular, (1) it is shown that if some cartesian power of an algebraic vector field admits a nontrivial rational first integral then already the second power does, (2) two-dimensional isotrivial algebraic vector fields admitting no nontrivial rational first integrals are classified up to birational equivalence, (3) a structural dichotomy is established for algebraic vector fields (of arbitrary dimension) whose finite covers admit no nontrivial factors, and (4) a necessary condition is given on the Albanese map of a smooth projective algebraic variety in order for it to admit an algebraic vector field having no nontrivial rational first integrals. Analogues in bimeromorphic geometry, for families of compact Kaehler manifolds parametrised by Moishezon varieties, are also obtained. These theorems are applications of a new tool here introduced into the model theory of differentially closed fields of characteristic zero (and of compact complex manifolds). In such settings, it is shown that a finite rank type that is internal to the field of constants, C, admits a maximal image whose binding group is an abelian variety in C. The properties of such "abelian reductions" are investigated. Several consequences for types over constant parameters are deduced by combining the use of abelian reductions with the failure of the inverse differential Galois problem for linear algebraic groups over C. One such consequence is that if p is over constant parameters and not C-orthogonal then the second Morley power of p is not weakly C-orthogonal. Statements (1) through (4) are geometric articulations of these consequences.Comment: 32 page

Le Parc National D’al Hoceima: Panorama Entre Terre Et Mer

Conserving, protecting and enhancing are the main pillars of the creation of National Parks in Morocco. Citing the Al Hoceima National Park characterizing by exclusivities among them one quotes; the presence of emblematic species such as the osprey and cedar, which are the logo symbol of this park, the only one in Morocco that includes a land part and the other marine part and has a view of the Mediterranean Sea, which summarizes a pleasant panorama between land and sea, with a mountainous aspect composed of cliffs and caves that constitute a habitat for monk seals that has disappeared and some bird species such as the osprey, islets and rocks housing several reptile species. This park is a place that meets the needs of land and marine enthusiasts practicing their leisure activities and is also a destination for researchers who participate in the management and preservation of the biodiversity of this environment, which requires the existence of certain cottages by ensuring the comfort and relaxation of visitors in this natural environment in order to develop sustainable tourism with good practice in nature conservation. From this article we focus on the avifauna which is the osprey, also on the plant species concerning the Berber cedar in terms of monitoring and conservation without forgetting the ecotourism which plays a main role in the sustainable development of Al Hoceima National Park by involving the principle of close participation.Conserver, protéger et valoriser sont des piliers principaux de la création des Parcs Nationaux au Maroc. Citant le Parc National d’Al Hoceima caractérisant par des exclusivités parmi eux on cite ; la présence des espèces emblématiques tel que le balbuzard pêcheur et le thuya qui sont le symbole de logo de ce parc ; le seul au Maroc qui englobe une partie terrestre et l’autre partie marine et qui a une vue sur la mer méditerranée ce qui résume un panorama agréable entre terre et mer, avec un aspect montagneux composé des falaises et des grottes, qui constitue un habitat de phoque moine qui a disparu et certains espèces ornithologues comme le balbuzard pêcheur, des îlots et des rochers abritant plusieurs espèces des reptiles. Ce Parc est un endroit qui réponds aux besoins des amateurs pratiquant leurs loisirs et aussi c’est une destination pour les chercheurs qui participent à la gestion et à la préservation de la biodiversité de ce milieu ce qui impose l’existence des certains gites en assurant le confort et la détente des visiteurs dans ce milieu naturel afin de développer le tourisme durable avec la bonne pratique de la conservation de la nature.A partir de cet article on met l’accent sur l’avifaune qui est le balbuzard pêcheur, aussi sur l’espèce végétal concernant le thuya de Berbérie en matière de suivi et conservation sans oublié l’écotourisme qui joue un rôle principale dans le développement durable du Parc National D’al Hoceima en impliquant le principe de la proche participative

Le code switching dans le processus de l’action didactique des enseignants à l’école publique marocaine

De par cette étude, nous visons à saisir l’impact de  l’utilisation de la langue maternelle (l’arabe dialectal dans notre cas) dans un cours de français sur le niveau des élèves et à cerner les facteurs qui motivent le recours à cette opération dans l’acte d’enseignement  du français à l’école publique.Ce travail est basé sur une enquête de terrain fondée sur le questionnaire. La population enquêtée est représentée par un échantillon d’enseignants du primaire

La langue maternelle dans l’enseignement du français à l’école publique marocaine

Résumé:Ce travail met la lumière sur le phénomène de l’alternance codique au sein des classes de français de l’école publique marocaine. Il se base sur l’observation participante des cours comme technique d’enquête afin d’examiner son type, sa fonction, et son impact sur le niveau des élèves.:ملخصهذا العمل يسلط الضوء على ظاهرة التناوب اللغوي داخل أقسام تدريس اللغة الفرنسية بالمدرسة العمومية المغربية وهو يعتمد على ملاحظة الدروس كتقنية للبحث من أجل فحص نوع الظاهرة ودورها وتأثيرها على مستوى التلاميذ

SOA formation from the atmospheric oxidation of 2-methyl-3-buten-2-ol and its implications for PM_2.5

The formation of secondary organic aerosol (SOA) generated by irradiating 2-methyl-3-buten-2-ol (MBO) in the presence and/or absence of NO_x, H₂O₂, and/or SO₂ was examined. Experiments were conducted in smog chambers operated in either dynamic or static mode. A filter/denuder sampling system was used for simultaneously collecting gas- and particle-phase products. The structural characterization of gas and particulate products was investigated using BSTFA, BSTFA + PFBHA, and DNPH derivatization techniques followed by GC-MS and liquid chromatography analysis. This analysis showed the occurrence of more than 68 oxygenated organic compounds in the gas and particle phases, 28 of which were tentatively identified. The major components observed include 2,3-dihydroxyisopentanol (DHIP), 2-hydroxy-2-oxoisopentanol, 2,3-dihydroxy-3-methylbutanal, 2,3-dihydroxy-2-methylsuccinic acid, 2-hydroxy-2-methylpropanedioic acid, acetone, glyoxal, methylglyoxal, glycolaldehyde, and formaldehyde. Most of these oxygenated compounds were detected for the first time in this study. <br><br> While measurements of the gas-phase photooxidation products have been made, the focus of this work has been an examination of the particle phase. SOA from some experiments was analyzed for the organic mass to organic carbon ratio (OM/OC), the effective enthalpy of vaporization (&Delta;H_vap^eff), and the aerosol yield. Additionally, aerosol size, volume, and number concentrations were measured by a Scanning Mobility Particle Sizer coupled to a Condensation Particle Counter system. The OM/OC ratio was 2.1 in the MBO/H₂O₂ system. The ΔH_vap^eff was 41 kJ mol⁻¹, a value similar to that of isoprene SOA. The laboratory SOA yield measured in this study was 0.7% in MBO/H₂O₂ for an aerosol mass of 33 μg m⁻³. Secondary organic aerosol was found to be negligible under conditions with oxides of nitrogen (NO_x) present. Time profiles and proposed reaction schemes are provided for selected compounds. <br><br> The contribution of SOA products from MBO oxidation to ambient PM_2.5 was investigated by analyzing a series of ambient PM_2.5 samples collected in several places around the United States. In addition to the occurrence of several organic compounds in both field and laboratory samples, DHIP was found to originate only from the oxidation of MBO, and therefore this compound could potentially serve as a tracer for MBO SOA. Initial attempts have been made to quantify the concentrations of DHIP and other compounds based on surrogate compound calibrations. The average concentrations of DHIP in ambient PM_2.5 samples from Duke Forest in North Carolina ranged from zero during cold seasons to approximately 1 ng m⁻³ during warm seasons. This appears to be the first time that DHIP has been detected in ambient PM_2.5 samples. The occurrence of several other compounds in both laboratory and field samples suggests that SOA originating from MBO can contribute under selected ambient conditions to the ambient aerosol mainly in areas where MBO emissions are high

The formation of secondary organic aerosol from the isoprene + OH reaction in the absence of NO_x

The reaction of isoprene (C₅H₈) with hydroxyl radicals has been studied in the absence of nitrogen oxides (NO_x) to determine physical and chemical characteristics of the secondary organic aerosol formed. Experiments were conducted using a smog chamber operated in a steady-state mode permitting measurements of moderately low aerosol levels. GC-MS analysis was conducted to measure methyl butenediols in the gas phase and polyols in the aerosol phase. Analyses were made to obtain several bulk aerosol parameters from the reaction including values for the organic mass to organic carbon ratio, the effective enthalpy of vaporization (ΔH_vap^eff), organic peroxide fraction, and the aerosol yield. <br><br> The gas phase analysis showed the presence of methacrolein, methyl vinyl ketone, and four isomers of the methyl butenediols. These gas-phase compounds may serve as precursors for one or more of several compounds detected in the aerosol phase including 2-methylglyceric acid, three 2-methyl alkenetriols, and two 2-methyl tetrols. In contrast to most previous studies, the 2-methyl tetrols (and the 2-methyl alkenetriols) were found to form in the absence of acidic sulfate aerosol. However, reaction conditions did not favor the production of HO₂ radicals, thus allowing RO₂+RO₂ reactions to proceed more readily than if higher HO₂ levels had been generated. <br><br> SOA/SOC (i.e. OM/OC) was found to average 1.9 in the absence of NO_x. The effective enthalpy of vaporization was measured as 38.6 kJ mol^&minus;1, consistent with values used previously in modeling studies. The yields in this work (using an independent technique than used previously) are lower than those of Kroll et al. (2006) for similar aerosol masses. SOC yields reported in this work range from 0.5–1.4% for carbon masses between 17 and 49 μgC m^&minus;3