Dernièrement, les finalités de l’enseignement des sciences sont évoluées vers le développement des citoyens dotés d’une culture scientifique et capables de piloter l’essor des pays. Et pour avoir une ...culture scientifique (l’objectif de tout enseignement scientifique), il faut posséder la connaissance et la compréhension des concepts et des processus scientifiques nécessaires pour prendre des bonnes décisions sur des questions personnelles et sociétales. En outre, la compréhension de ces constructions épistémologiques appelés nature de la science (NOS) par les enseignants est très importante pour améliorer la compréhension des sciences par les élèves Cette étude explore et analyse l’idée de science chez des enseignants Marocains des sciences de la vie et de la terre. Des entretiens semi-structurés et une analyse qualitative du contenu sont utilisés pour explorer ces idées. Les enseignants ont montré une certaine hétérogénéité des conceptions. Ces derniers ont des idées différentes sur la science. Parfois suffisantes, parfois incorrectes. Ainsi, cette étude met en évidence une carence culturelle profonde en matière de réflexion sur la nature de la science et les modes d’élaboration du savoir scientifique. D’où l’importance de l’introduction de l’épistémologie dans la formation de ces enseignants.
Recently, the aims of science education have evolved towards developing citizens with scientific literacy and the ability to drive national progress. To achieve scientific literacy (the goal of all science education), individuals must possess knowledge and understanding of scientific concepts and processes necessary for making informed decisions on personal and societal issues. Furthermore, teachers’ comprehension of these epistemological constructs known as the nature of science (NOS) is crucial for enhancing students’ understanding of science.This study explores and analyzes the concept of science among Moroccan life and earth science teachers. Semi-structured interviews and qualitative content analysis are used to explore these ideas. The teachers exhibited some heterogeneity in their conceptions, with different ideas about science, some of which were adequate while others were incorrect. Therefore, this study highlights a profound cultural deficiency in reflecting on the nature of science and the modes of scientific knowledge construction. Hence, the introduction of epistemology in the training of these teachers is essential.
Le constructivisme est une approche pédagogique majeure dans l’enseignement des sciences, mettant l’accent sur l’implication active des apprenants dans la construction de leur propre connaissance. ...Cependant, les études menées au Maroc révèlent un faible niveau de compétences en sciences de la vie et de la terre chez les élèves, révélant des lacunes dans leur compréhension des concepts scientifiques. Dans ce contexte, notre recherche se concentre sur la pratique enseignante des professeurs de sciences de la vie et de la terre (SVT) au Maroc, en examinant plus précisément le rôle des conceptions initiales des élèves. Notre objectif est d’étudier comment les enseignants abordent ces conceptions dans leur pratique pédagogique et comment cela influence l’enseignement du concept d’écosystème en sciences de la vie et de la terre. Pour mener cette étude, nous avons utilisé un questionnaire à choix multiple pour collecter des données auprès des enseignants de SVT dans différentes académies régionales du Maroc. En analysant leur pratique, nous cherchons à déterminer quelle approche est adoptée par les enseignants et comment cela peut influencer la construction des concepts scientifiques chez les élèves marocains. Notre objectif ultime est d’améliorer l’apprentissage des sciences en identifiant les meilleures pratiques pédagogiques qui favorisent une meilleure compréhension des concepts scientifiques, en particulier le concept d’écosystème, chez les élèves marocains.
Constructivism is a major pedagogical approach in science education, emphasizing the active involvement of learners in the construction of their own knowledge. However, studies conducted in Morocco reveal a low level of competence in life and earth sciences among students, revealing gaps in their understanding of scientific concepts. In this context, our research focuses on the teaching practice of life and earth sciences (SVT) teachers in Morocco, by examining more precisely the role of students’ initial conceptions. Our objective is to study how teachers approach these conceptions in their pedagogical practice and how this influences the teaching of the concept of ecosystem in life and earth sciences. To conduct this study, we used a multiple choice questionnaire to collect data from SVT teachers in different regional academies in Morocco. By analyzing their practice, we seek to determine which approach is adopted by teachers and how this can influence the construction of scientific concepts among Moroccan students. Our ultimate goal is to improve science learning by identifying the best pedagogical practices that promote a better understanding of scientific concepts, in particular the concept of ecosystem, among Moroccan students.
We investigate an interval of moderate magnetic activity from 0–8 UT on 14 March 2008 by using a global magnetohydrodynamics (MHD) simulation with high spatial and temporal resolution. Observations ...show several distinct substorms during this interval. One of these with onset at 04:44 UT occurs at 04:42 UT in the simulation. The simulation shows reconnection is continuously present at multiple sites. During the growth phase, the number of X‐lines decreases as their total length increase and their locations approach the Earth. The X‐lines create multiple fast flow channels with dipolarization fronts. The total length and area of these channels increase during the growth phase as they penetrate closer to the Earth carrying more magnetic flux. The 04:42 UT onset in the simulation was preceded by the growth of an X‐line that eventually extended 55 RE from 12 RE premidnight to 50 on the dawn side. It produced a narrow flow channel parallel to the X‐line that eventually penetrated inside 10 RE rapidly depositing magnetic flux as the expansion phase developed. Despite this good agreement in expansion phase onset time, ground and satellite observations suggest a quiet growth phase with a sudden onset of reconnection. It may be possible to explain the difference between observations and simulations if all growth phase activity in the simulation maps to the ionosphere at very high latitudes. An auroral streamer at onset maps in the simulation very close to Earth. A recovery phase streamer maps to the middle tail.
Plain Language Summary
The solar wind confines the Earth's magnetic field to a volume called the magnetosphere. When the solar wind magnetic field is antiparallel to the Earth's field they connect in a process called reconnection. This links dipole field lines to the solar wind field that then drags ant sunward creating a long tail. When forced together in the tail, they reconnect and return to the dayside. These processes are studied using numerical simulations that solve the basic equations of magnetized fluids called magnetohydrodynamics (MHD). Spacecraft and ground‐based observations suggest that there is a growth phase of quiet thinning before the onset of a major reconnection event. The simulations described here behave differently. They indicate that reconnection is continuously present producing bursts of earthward flowing plasma. As the growth phase progresses, the reconnection becomes more intense and moves closer to the Earth, and the flow channels lengthen, carry more magnetic flux, and penetrate closer to Earth. At some point, flux accumulates near local midnight, and auroral and ionospheric currents expand poleward. We have too few satellites in the tail to determine if this is true observationally. The interaction of a narrow flow channel with the ionosphere creates a narrow streak of aurora.
Key Points
Reconnection and fast flows are continuously present and produce expansions when magnetic flux accumulates in the outer magnetosphere
Auroral streamers map to fast flows generated close to the Earth
The simulation suggests that fast flows do not come from an X‐line beyond the Moon
The Source of Auroral Omegas Weygand, J. M.; El‐Alaoui, M.; Nykyri, H. K.
Journal of geophysical research. Space physics,
January 2022, 2022-01-00, 20220101, Letnik:
127, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The auroral wave‐like structures called “omega bands” appear within the post‐midnight sector auroral oval with shapes resembling the Greek letter omega, and are typically associated with the recovery ...phase of substorms. Prior work and MHD simulations suggest both high speed earthward flows and post‐midnight flow shears are possible omega band source mechanisms. However, what produces omega bands is not well understood. It is most likely that the paucity of concurrent magnetospheric data has limited our ability to understand fully the mechanism responsible for the generation of the omega bands. We have identified about 263 auroral omegas in seven different THEMIS all sky cameras (ASCs) over a 10 year period. A fraction appear to form from north‐south streamers, but some appear to form from east‐west auroral arcs. Fifty‐one of the 263 Ω also have conjugate or near conjugate THEMIS and GOES spacecraft data. There is evidence in about 80% of these events that high speed earthward flows have occurred prior to or at about the same time as the auroral omega observation. This evidence consists of high speed earthward flows, magnetic field dipolarizations, particle injections into the inner magnetosphere, and auroral streamers. 11 events also show plasma flow data azimuthally along the inner magnetosphere, but for six of these events the Vy component is inconsistent with the auroral omega direction of motion. Of the remaining five events, four have Vy flow shear events but also show evidence of magnetic field dipolarizations, particle injections into the inner magnetosphere, and auroral streamers. Our observations suggest high speed earthward flows are more likely to be the source of auroral omega bands.
Key Points
We show several examples of hemispherically conjugate auroral omegas, which demonstrates their source is within the magnetotail
Conjugate ASIs of omegas and spacecraft magnetic field and particle data show that ∼80% of events are correlated with high speed flows
Only 10% of the events appear to occur during high speed dawnward flows, which could be associated with a Kelvin‐Helmholtz instability
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•PLS vs. MCR-ALS for ciprofloxacin quantitation by FT-NIR in various cases.•In the same matrix, both methods demonstrated good quantitation with low errors.•PLS struggled with varying ...matrix compositions, while MCR-ALS excelled.•PLS showed errors in quantitating ciprofloxacin with new excipients.•MCR-ALS achieved accurate quantitation across all samples.
This study aims to quantify ciprofloxacin in commercial tablets with varying excipient compositions using Fourier Transform Near-Infrared Spectroscopy (FT-NIR) and chemometric models: Partial Least Squares (PLS) and Multivariate Curve Resolution - Alternating Least Squares (MCR-ALS).
Matrix variation, arising from differences in excipient compositions among the tablets, can impact quantification accuracy. We discuss this phenomenon, emphasizing potential issues introduced by varying certain excipients and its importance in reliable ciprofloxacin quantification.
We evaluated the performance of PLS and MCR-ALS models independently on two sets of tablets, each containing the same drug substance but different excipients. The statistical results revealed promising results with PLS prediction error of 0.38% w/w of the first set and 0.47% w/w of the second set, while MCR-ALS achieved prediction errors of 0.67% w/w of the first set and 1.76% w/w of the second set.
To address the challenge of matrix variation, we developed single models for PLS and MCR-ALS using a dataset combining both first and second sets. The PLS single model demonstrated a prediction error of 4.3% w/w and a relative error of 6.41% w/w, while the MCR-ALS single model showed a prediction error of 1.88% w/w and a relative error of 1.29% w/w.
We then assessed the performance of the single PLS and MCR-ALS models developed based on the combination of the first and the second set in quantifying ciprofloxacin in various commercial tablet brands containing new excipients. The PLS model achieved a prediction error ranging between 6.2% w/w and 8.39% w/w, with relative errors varied between 8.53% w/w and 12.82% w/w. On the other hand, the MCR-ALS model had a prediction error between 1.11% w/w and 2.66% w/w, and the relative errors ranging from 0.8% to 1.74% w/w.
MMS observations recently confirmed that crescent‐shaped electron velocity distributions in the plane perpendicular to the magnetic field occur in the electron diffusion region near reconnection ...sites at Earth's magnetopause. In this paper, we reexamine the origin of the crescent‐shaped distributions in the light of our new finding that ions and electrons are drifting in opposite directions when displayed in magnetopause boundary‐normal coordinates. Therefore, E × B drifts cannot cause the crescent shapes. We performed a high‐resolution multiscale simulation capturing subelectron skin‐depth scales. The results suggest that the crescent‐shaped distributions are caused by meandering orbits without necessarily requiring any additional processes found at the magnetopause such as the highly asymmetric magnetopause ambipolar electric field. We use an adiabatic Hamiltonian model of particle motion to confirm that conservation of canonical momentum in the presence of magnetic field gradients causes the formation of crescent shapes without invoking asymmetries or the presence of an E × B drift. An important consequence of this finding is that we expect crescent‐shaped distributions also to be observed in the magnetotail, a prediction that MMS will soon be able to test.
Key Points
Electron and ion velocity distributions have crescent shapes in opposite directions
The magnetopause electric field is not a determining factor in forming the crescent distributions
Crescent distributions are caused by the meandering particles in thin magnetic field reversal
Introduction L’orbitopathie dysthyroïdienne (OD) représente la manifestation extra-thyroïdienne la plus fréquente des affections thyroïdiennes auto-immunes (maladie de Basedow, thyroïdite ...d’Hashimoto). Afin d’en améliorer la prise en charge diagnostique et thérapeutique, une consultation multidisciplinaire (endocrinologue, ophtalmologue, chirurgien maxillo-facial) a été mise en place au CHU de Toulouse depuis 1995. Résultats Au total, 726 patients ont été vus entre 1995 et 2013 avec une incidence annuelle de 50 nouveaux patients durant les 5 dernières années. La population était majoritairement féminine (83 %), âgée en moyenne de 48,5 ans (± 13,2). Responsable de la majorité des OD (90 %), la maladie de Basedow était traitée par antithyroïdiens de synthèse (34 %), thyroïdectomie totale (9 %), iode radioactif (2 %) seuls ou en association. Dix-neuf pour cent des patients ont présenté un passage en hypothyroïdie et 40 % étaient tabagiques actifs. L’OD était précessive (12 %), concomitante (38 %) ou diagnostiquée après la thyrotoxicose (50 %). Les patients présentaient une rétraction de la paupière supérieure (82,5 %), une exophtalmie (73 %) et/ou une diplopie (43 %). L’OD était minime (43 %), modérée (27 %), sévère (30 %). L’OD était plus sévère chez les sujets âgés (< 0,001), de sexe masculin (0,001), traités par iode radioactif (< 0,001) et ayant présenté un passage en hypothyroïdie (0,004). Seul un traitement radioactif chez une femme était significativement associé à la sévérité de l’OD (OR = 5,07, IC 95 % = 2,79–9,21, p < 0,001) après analyse de régression multivariée. Conclusion Nous décrivons, à travers cette cohorte importante de patients, les caractéristiques épidémiologiques de l’OD prise en charge au sein d’une consultation multidisciplinaire durant les deux dernières décennies.
The Relation of N‐S Auroral Streamers to Auroral Expansion McPherron, R. L.; El‐Alaoui, M.; Walker, R. J. ...
Journal of geophysical research. Space physics,
April 2020, 2020-04-00, 20200401, Letnik:
125, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We investigate the relation of fast flows at the inner edge of the plasma sheet to the onset of auroral expansion. Recent work suggests that nearly all expansions are an instability triggered by an ...auroral streamer from far out in the magnetotail. We investigate an 8‐hr interval of activity on 14 March 2008 using ground magnetometer and all‐sky camera data to determine the onset times of six substorm expansions. We compare these times with Time History of Events and Macroscale Interactions during Substorms observations of plasma flow and magnetic field. We show that every expansion followed the arrival of a fast flow and dipolarization event at the inner edge of the plasma sheet. To relate the aurora to flows, we develop procedures for removing fixed lights, the moving Moon and its reflection, and contamination due to scattered moonlight. We scan movies of enhanced images for auroral streamers. Three onsets were tentatively associated with streamers. For two, the apparent source was very close to the growth phase arc mapping close to Earth. For one, an onset occurred in the recovery phase of an earlier substorm after a double oval had formed. For this one, the end of an N‐S streamer stopped about 2° north of the breakup arc. For the remaining three expansions, no streamers were associated with the onsets. Most substorms exhibit N‐S streamers in the recovery phase. These usually cannot be associated with fast flows. Either fast flows in the growth phase do not produce streamers or they make streamers that require significant image enhancement.
Plain Language Summary
Auroral streamers are narrow bands of auroral luminosity that originate near the poleward edge of the auroral oval. They generally propagate from north to south often with a large azimuthal component. Researchers think that these streamers impact the outer magnetosphere triggering an instability that appears as a localized expansion of aurora towards the poles. This paper describes the processing of ground auroral images to identify the existence of streamers. We compare their occurrence with ground magnetometer data signaling the onset of auroral expansion and with spacecraft data showing high‐speed flows transporting magnetic flux to the inner edge of the plasma sheet. We find that all six expansions were associated with the arrival of fast flows transporting magnetic flux towards Earth. Only three of these could be associated with a streamer. Two were primarily E‐W from a source close to Earth. The third was a classic N‐S streamer that occurred in the recovery phase of an earlier substorm. At this time, aurora was present in two bands at the edges of the auroral oval. There was no obvious connection of the equatorward end of this streamer to the activated arc. We find that the fast flows causing substorm expansion either do not produce visible aurora or are so weak that special processing of the camera images is required to see the streamers.
Key Points
All six auroral expansions in the study interval were preceded by the arrival of a bursty bulk flow at inner edge of plasma sheet
Only three of the fast flows were definitely associated with auroral streamers
Only one expansion occurred when classic streamers originating at the poleward edge of the auroral oval were present
We report Magnetospheric Multiscale observations of high‐frequency electrostatic waves in the vicinity of the reconnection ion diffusion region on the dayside magnetopause. The ion diffusion region ...is identified during two magnetopause crossings by the Hall electromagnetic fields, the slippage of ions with respect to the magnetic field, and magnetic energy dissipation. In addition to electron beam modes that have been previously detected at the separatrix on the magnetospheric side of the magnetopause, we report, for the first time, the existence of electron cyclotron harmonic waves at the magnetosheath separatrix. Broadband waves between the electron cyclotron and electron plasma frequencies, which were probably generated by electron beams, were found within the magnetopause current sheet. Contributions by these high‐frequency waves to the magnetic energy dissipation were negligible in the diffusion regions as compared to those of lower‐frequency waves.
Key Points
Ion diffusion region was identified by MMS spacecraft in the Earth's dayside magnetopause
High‐frequency electrostatic waves were observed in the vicinity of the ion diffusion region
Energy dissipated by these high‐frequency waves is negligible compared to that by the lower‐frequency process
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