LE PEUPLEMENT DE L’ASIE DU SUD-EST PAR HOMO SAPIENS : ANALYSE DE LA VARIABILITE MORPHOLOGIQUE DES MOLAIRES DEFINITIVES HUMAINES

The biological diversity of modern humans in Southeast Asia has long been regarded as resulting of two major migrations waves. Nevertheless, alternative and/or more complex scenarios have also been proposed. Analysis of the morphological variability of osteological and dental archaeological series is a corner stone as they are direct evidence of the main past events that shaped the modern human diversity in the region. The present study is based on a comparative analysis of the crown contour shape of permanent modern human molars with the combined advantages of a large archaeological sampling and the use of methods which allow detecting and quantifying low intraspecific morphological changes (size and shape of human teeth have a high degree of heritabiliy). The sample includes 1537 modern human molars from Mainland and Island Southeast Asia, Australia and Melanesia; 661 are coming from various chrono‐cultural periods spanning from the Upper Pleistocene to the sub‐actual period. Important methodological developments presented in this work circumvent major difficulties due to particular crown features of human molars: (i) development of a new procedure for the normalization (= standardization) of molar crown outlines that allows using elliptic Fourier analysis, (ii) creation of a new method for the determination of the rank of isolated modern human molars that is highly reliable (≤5% of misclassifications). Our results, based on quantified patterns of shape and size diversity, morphological affinities as well as elaboration and test of design matrices modeling main hypotheses for the peopling of Southeast Asia, are congruent with scenarios based on series of migratory processes since the Upper Pleistocene. Sea level variations (especially at the Last Glacial Maximum) and demic diffusion of the “Neolithic” in certain regions are likely to impact significantly on the structure of the biological diversity of modern humans in Southeast Asia. The major outcomes of the present study are congruent with the results of several recent genetic works in the region. In conclusion, Southeast Asia is a key region for future development aiming at understanding the history and diversity of Homo sapiens

Small Size in the Philippine Human Fossil Record: Is It Meaningful for a Better Understanding of the Evolutionary History of the Negritos?

Pygmy populations are recognized in several places over the world, especially in Western Africa and in Southeast Asia (Philippine negritos, for instance). Broadly defined as small-bodied Homo sapiens (compared with neighboring populations), their origins and the nature of the processes involved in the maintenance of their phenotype over time are highly debated. Major results have been recently obtained from population genetics on present-day negrito populations, but their evolutionary history remains largely unresolved. We present and discuss the Upper Pleistocene human remains recovered from Tabon Cave and Callao Cave in the Philippines, which are potentially highly relevant to these research questions. Human fossils have been recovered in large numbers from Tabon Cave (Palawan Island) but mainly from reworked and mixed sediments from several archaeological layers. We review and synthesize the long and meticulous collaborative work done on the archives left from the 1960s excavations and on the field. The results demonstrate the long history of human occupations in the cave, since at least ~30,000 BP. The examination of the Tabon human remains shows a large variability: large and robust for one part of the sample, and small and gracile for the other part. The latter would fit quite comfortably within the range of variation of Philippine negritos. Farther north, on Luzon Island, the human third metatarsal recently recovered from Callao Cave and dated to ~66,000 BP is now the oldest direct evidence of human presence in the Philippines. Previous data show that, compared with H. sapiens (including Philippine negritos), this bone presents a very small size and several unusual morphological characteristics. We present a new analytical approach using three-dimensional geometric morphometrics for comparing the Callao fossil to a wide array of extant Asian mammals, including nonhuman primates and H. sapiens. The results demonstrate that the shape of the Callao metatarsal is definitely closer to humans than to any other groups. The fossil clearly belongs to the genus Homo; however, it remains at the margin of the variation range of H. sapiens. Because of its great antiquity and the presence of another diminutive species of the genus Homo in the Wallace area during this time period (H. floresiensis), we discuss here in detail the affinities and potential relatedness of the Callao fossil with negritos that are found today on Luzon Island

Elephant impact on the large tree component and its potential effect on selected fauna

The aim of the study was to determine the consequences of elephant (Loxodonta africana) impact on selected nesting sites of avian fauna and other species in the Associated Private Nature Reserves. The study also aimed at answering key questions on how the architecture of trees influence nest site suitability and what landscape features affect nest site location. Furthermore the type of impact that elephants have on specific nesting sites was determined and how this would affect the short term persistence of these trees. The facillitatory role of elephants was examined by looking at the type of impact that produces gum exudants as well as what gum is selected for by primates and whether primary branch breaking may lead to the creation of nesting sites for species such as the southern ground hornbill (Bucorvus leadbeateri).Environmental SciencesM. Sc. (Environmental Management

Wave-mixing origin and optimization in single and compact aluminum nanoantennas

The outstanding optical properties for plasmon resonances in noble metal nanoparticles enable the observation of non-linear optical processes such as second-harmonic generation (SHG) at the nanoscale. Here, we investigate the SHG process in single rectangular aluminum nanoantennas and demonstrate that i) a doubly resonant regime can be achieved in very compact nanostructures, yielding a 7.5 enhancement compared to singly resonant structures and ii) the $\chi_{\perp\perp\perp}$ local surface and $\gamma_{bulk}$ nonlocal bulk contributions can be separated while imaging resonant nanostructures excited by a tightly focused beam, provided the $\chi_{\perp\parallel\parallel}$ local surface is assumed to be zero, as it is the case in all existing models for metals. Thanks to the quantitative agreement between experimental and simulated far-field SHG maps, taking into account the real experimental configuration (focusing and substrate), we identify the physical origin of the SHG in aluminum nanoantennas as arising mainly from $\chi_{\perp\perp\perp}$ local surface sources

Can a two-hour lecture by a pharmacist improve the quality of prescriptions in a pediatric hospital? A retrospective cohort study

Background: A high rate of prescription errors exists in pediatric teaching hospitals, especially during initial training.Objectives: To determine the effectiveness of a two-hour lecture by a pharmacist on rates of prescription errors and quality of prescriptions.Methods: A two-hour lecture led by a pharmacist was provided to 11 junior pediatric residents (PGY-1) as part of a one-month immersion program. A control group included 15 residents without the intervention. We reviewed charts to analyze the first 50 prescriptions of each resident.Results: Data were collected from 1300 prescriptions involving 451 patients, 550 in the intervention group and 750 in the control group. The rate of prescription errors in the intervention group was 9.6% compared to 11.3% in the control group (p=0.32), affecting 106 patients. Statistically significant differences between both groups were prescriptions with unwritten doses (p=0.01) and errors involving overdosing (p=0.04). We identified many errors as well as issues surrounding quality of prescriptions.Conclusion: We found a 10.6% prescription error rate. This two-hour lecture seems insufficient to reduce prescription errors among junior pediatric residents. This study highlights the most frequent types of errors and prescription quality issues that should be targeted by future educational interventions

Homo luzonensis : principales caractéristiques et implications pour l’histoire évolutionnaire du genre

La nouvelle espèce Homo luzonensis a été décrite en 2019 à partir d’un assemblage constitué de treize éléments fossiles découverts dans la grotte de Callao (île de Luzon, Philippines) en 2007, 2011 et 2015. La datation directe de deux de ces fossiles par les séries de l’uranium indique des âges minimums respectifs de 50 000 et 67 000 ans. Dans cette présentation, nous montrons que ces spécimens présentent une combinaison de caractéristiques morphologiques primitives (i.e. ressemblant à Austra..

Teaching discourses of French as a second language : case study understanding expositive History and Geography texts for newly-arrived allophone children in the French schooling system

La recherche s’inscrit dans le cadre de la didactique du français langue seconde en contexte scolaire. Elle a pour objet d’étude les textes expositifs, c’est-à-dire ceux qui synthétisent les éléments de savoirs à acquérir. A partir de l’analyse d’un corpus de textes expositifs extraits de manuels scolaires de cycle 3 d’histoire et de géographie, la recherche se propose de définir une démarche explicite de la compréhension adaptée aux compétences et aux besoins des élèves allophones nouvellement arrivés. Pour cela, les facteurs d’hétérogénéité, le contexte de la scolarisation, les caractéristiques de ces textes et le processus de compréhension en lecture en langue seconde sont explorés. La démarche envisagée se veut active et collaborative et comprend deux étapes essentielles : un enrichissement préalable des connaissances linguistiques orales des élèves puis des activités variées qui permettent des manipulations sur le texte, notamment expansion, reformulation, surlignage ou déplacement d’éléments linguistiques et développement progressif de la complexité syntaxique. Dans une troisième étape, complémentaire, le texte expositif devient un support privilégié pour initier les élèves allophones à l’étude du fonctionnement de la langue française, les apprentissages menés venant soutenir, dans un mouvement de va-et-vient la compréhension en lecture.La recherche se veut conjointement une contribution à l’étude des discours d’enseignement dans leur modalité écrite et à la réflexion méthodologique de la didactique du français langue seconde dans le système éducatif français.The research is related to didactics of French as a second language in a schooling context. It is based on the study of expositive texts, those which synthetize the parts of knowledge to be acquired. Based on the analysis of a corpus of expositive texts taken from primary school Geography and History books, the research subject tries to define an explicit teaching approach adapted to skills and needs of newly-arrived allophone pupils.For that purpose, shared mixed factors in the audience, the context in which pupils attend school, characteristics of expositive texts (for which we provide a typology), and the process in reading comprehension as a second language will be deeply studied. The approach which will be then considered tends to be active and collaborative and has two essential steps : first an enrichment of the pupils' oral linguistic knowledge, then various activities enabling to apprehend the text such as expanding it, rephrasing it, highlighting linguistic phrases or moving them in the text, and finally developing syntactic complexity in a progressive way.In a third step, which will be complementary, the expositive text becomes the major medium to initiate allophone pupils to the study of the functioning of French language, bearing in mind that carried out learnings will constantly help reading comprehension throughout the lesson.The research also wants to contribute to the study of written teaching methods and a methodological thought concerning didactics of French as a second language in the French educational system

Book review: "Unearthing prehistory: The archaeology of Northeastern Luzon, Philippine islands". Armand Salvador Mijares. 2007

The book "Unearthing Prehistory: The Archaeology of Northeastern Luzon, Philippine Islands" tells the story of 50 years of archaeology in Northeastern Luzon. It discusses known archaeological information as well as it investigates different hypotheses and other important unresolved questions in the region

Caractérisation de la génération de second harmonique dans des nanostructures plasmoniques

Plasmonic nanostructures have the ability to support localised surface plasmon resonancescharacterized by a collective oscillation of the free electrons in metal. This phenomenon, knowto generate an intense local field, can be used to enhance nonlinear optical processes at thenanoscale level. In this thesis, we have investigated the second harmonic generation (SHG)process in aluminum and gold nanostructures. First, we have studied the origin of this nonlinearprocess and highlighted the major role played, in gold, by the bulk nonlocal contribution,originating from the field gradients inside the nanostructure volume. Then, we pointed out,by achieving a double resonance regime associated with a plasmonic mode matching at theexcitation and emission, the possibility to enhance significantly the harmonic response ofcompact aluminum nanoantennas. In order to increase even more the nonlinear intensity, anidea is to couple these nanostructures to a nonlinear nanocrystal to benficiate both from thefield enhancement provided by the metallic nanoantenna and from the nonlinearity of thenanocrystal. To optimise the harmonic intensity generated by these hybrid structures, havenanocrystals with a strong intrinsic nonlinearity is required. To this end, we have measuredthe harmonic response of single latanide iodate nanocrystals, in order to evaluate their abilityto integrate this type of structure. Moreover, we have implemented a near-field opticalmicroscope used to manipulate nancorystals in the vincinity of metallic nanostructures. Thisthesis, by bringing new elements to understand and optimise the SHG process in plasmonicnanostructures, provides new perspectives to elaborate efficient optical components tofrequency conversion at the nanoscale.Les nanostructures métalliques ont la capacité de supporter des résonances de plasmonsde surface localisés se caractérisant par une oscillation collective des électrons libres du métal.Ce phénomène, connu pour générer localement un champ électrique intense, peut notammentêtre exploité afin d’exalter les processus d’optique non-linéaire à l’échelle nanométrique. Aucours de cette thèse, nous nous sommes intéressés au processus de génération de second harmonique(SHG) de nanostructures en aluminium et en or. Tout d’abord, nous avons étudiél’origine du processus non-linéaire et mis en évidence le rôle important joué, dans l’or, parla contribution non-locale, issue des gradients de champ dans le volume de la nanostructure.Ensuite, nous avons montré, en associant un phénomène de double résonance et unaccord des modes plasmoniques à l’excitation et à l’émission, qu’il est possible d’exalter fortementla réponse harmonique d’une nanoantenne compacte en aluminium. Dans l’optiqued’obtenir une intensité non-linéaire encore plus importante, une stratégie est de coupler cesnanostructures à un nanocristal non-linéaire afin de bénéficier à la fois de la forte exaltationdu champ générée par le métal et de la non-linéarité du cristal. Afin d’optimiser l’intensitéharmonique générée par ces structures hybrides, disposer de nanocristaux possédant une fortenon-linéarité intrinsèque est nécessaire. C’est pourquoi, au cours de cette thèse, nous avonsmesuré la réponse harmonique de nanocristaux d’iodates de lantane isolés, afin d’estimer leurpotentiel pour intégrer ce type de structure. De plus, un microscope optique en champ prochea été mis en place sur le dispositif expérimental permettant la manipulation de nanocristauxà proximité de structures métalliques. Cette thèse, en apportant de nouveaux éléments pourcomprendre et optimiser le processus de SHG dans les nanostructures plasmoniques, offre denouvelles perspectives pour confectionner des composants optiques efficaces pour la conversionde fréquence à l’échelle nanométrique

Technical Note: Anatomic Identification of Isolated Modern Human Molars: Testing Procrustes Aligned Outlines as a Standardization Procedure for Elliptic Fourier Analysis

The determination of the precise position of permanent first and second modern human molars, following standard tooth identification criteria, is often difficult because of their morphological similarities. Here, we proposed to evaluate the suitability of two- dimensional crown contour shape analysis in achieving this objective. The method was tested separately on 180 first and second maxillary molars (UM) and 180 first and second mandibular molars (LM) securely identified (in anatomical position in their sockets). Generalized Pro- crustes superimposition is used to normalize the outlines prior to applying elliptic Fourier analyses ("EFAproc" method). Reliability and effectiveness of this morphomet- ric procedure was evaluated by comparing the results obtained for the same dataset with four other morpho- metric methods of contour analysis. Cross-validated ("leave one individual out") percentages of misclassifica- tion yielded by linear discriminant analyses were used for determining the anatomic position of modern human molars. The percentages of misclassifications obtained from every method of contour analysis were low (1.67% to 3.33% for the UM, 5.56% to 6.67% for the LM) indicat- ing the high suitability of crown contour analyses in cor- rectly identifying molars. A reliable protocol, based on predictive linear discriminant analyses, was then pro- posed for identification of isolated molars. In addition, our results confirmed that the EFAproc method is suita- ble for normalizing outlines prior to undertaking elliptic Fourier analyses, especially in the case of nearly circular outlines: it obtained better classification than the classic method of normalization of Fourier descriptors for UM and provided also some advantages over the three landmarks-based methods tested here