Analyses chimiques des eaux du fleuve Niger à Niamey : premiers résultats d'une campagne annuelle de mesures

Nous avons déterminé, d'août 1984 à février 1986, les concentrations des silicates, chlorures, nitrites, phosphates, potassium, sodium, calcium, magnésium, ammonium et fer ferrique ainsi que le pH, la conductivité, la turbidité, l'oxygène dissous, l'alcalinité et la D.B.O. dans l'eau du fleuve Niger à hauteur de la ville de Niamey. L'exploitation statistique de ces résultats fait apparaître l'existence de deux périodes stables et d'une période instable au cours de l'année. (Résumé d'auteur

Preliminary geoarchaeological data from a Senegambian megalithic world heritage site (Wanar, Senegal)

The Senegambian megalithic complex spread over a territory of 250 km from east to west and 120 to 150km from north to south. It consists of various monumental forms, especially erected stones circles. At the regional Senegambian scale the excavated sites suggest dates between 7th and 16th century AD, maby older. The exceptional concentration of the alignments and the originality of the forms (“lyre” stones, bifid stones, disc decorations, associated with other monuments, e.g. burial mounds) motivated  he inscription of four sites of Senegal and Gambia as World Heritage by UNESCO, like the site of Wanar in Senegal, in the watershed of the Bao Bolon, a tributary of the Gambia River (whc.unesco.org/en/list/1226). However, very little is known about the natural environment of these spectacular monumental manifestations, nor about the socio-economic context of their edification and the surrounding landscapes. Since 2005, archaeological excavations are carried out every year on the necropolis of Wanar. Such research contributes to enrich the socio-cultural knowledge of the Senegambian megalithism, phenomenon associated with the Protohistory (wanar-excavations.jimdo.com). Geoarchaeological studies (geomorphological and palaeo-biogeographical) currently in progress atWanar aim to reconstruct palaeoenvironments and landscapes contemporary of the monument construction, in order to answer a series of questions: In which landscape context have these populations developed? What were their relations with their environment? How did they fit into their territory, and how did they adapt to environmental changes? The dated material from two cores shows that the sedimentary records cover an extended timespan which include the Senegalese protohistory and previous periods (up to 5000 cal. BP). First sedimentological results describe the hydrosedimentary functioning of the Wanar watershed during the period contemporary with the megalithic phenomenon. Palaeoclimatic signals and anthropogenic impacts must be deciphered in order to better understand the fluctuating environmental dynamics of this era. The processing of grain size parameters, CM patterns (one-percentile/median) according to the method of Passega (1964), makes possible to well characterize the fluvial functioning and the depositional environments (ponds/stagnant water, flood plain or channel with low and intermittent current). These wetlands are very good recorders of palaeoenvironmental dynamics. Paleobiological multiproxies analysis (pollens, diatoms, dendrology, palynofacies and fire signal) are currently in progress and should allow the reconstruction of the history of vegetal landscapes and natural environments. Particular attention will be given to the dynamic factors linked to human activities (fires, vegetation clearing, agro-pastoral practices) and their imprint on the landscape

The Untold Stories from Covid-19: The Calamity of Implementing Curriculum During a Pandemic

In March 2020, the Covid-19 Pandemic wreaked havoc on our nation’s educational system. Students, teachers, and administrators were forced to engage in a new remote learning model, which was unfamiliar. This narrative study draws on the lived experiences of six K-12 teachers in Southwest Ohio urban school districts. The data analysis was examined through the lens of the Science of Learning and Development framework (SoLD). Findings highlight the impact of Covid-19 on curriculum implementation. Results show that unprepared teachers could not pivot to online learning effectively, which may intensify the educational gaps and inequities among students in six urban schools in Southwest Ohio

Prostaglandin E2-like activity of 20:3n-9 platelet lipoxygenase end-product

Abstract5,8,11-Icosatrienoic acid (20:3n-9), a fatty acid associated with platelet hyperactivity, was oxygenated by platelet lipoxygenase. The end-product of this pathway was purified by high-performance liquid chromatography (HPLC) and characterized as 12-hydroxy-5,8,10-icosatrienoic acid [12-OH-20:3(5,8,10)] by capillary gas-liquid mass spectrometry. When tested upon platelet aggregation, 12-OH-20:3(5,8,10) exhibited a biphasic effect. At low concentrations (below 5 × 10−7 M) it potentiated aggregation but inhibited it at higher levels, a pattern similar to that obtained with prostaglandin E2. However, since the amounts of 12-OH-20:3(5,8,10) generated under thrombin stimulation are in the range of concentrations with potentiating effects, it seems that the 12-OH derivative is responsible for the hyperaggrebility of 20: 3n-9-rich platelets

Examining the Montessori Lower Elementary Education as Pedagogy for Peace: A Study of an Alternative Framework to Address Bullying in Schools

Bullying among students continues to be a problem in schools and the numbers of incidents are increasing. There is an urgent need to find solutions to address this crisis in the United States. The purpose of this study is to examine the role of curriculum in shaping educational policy as an effective framework to address the social concerns of bullying in the 21st century. The research focuses on Montessori education as pedagogy for peace and on how the Montessori lower elementary curriculum addresses bullying. In addition, the study analyzes the Montessori peace initiatives with the policy implications of the New York State Dignity for All Students Act (DASA), enacted in July 2012, as a law attempting to address bullying through enforcement and monitoring. The Montessori lower elementary education is investigated in the study using a mixed methods approach. This method allowed the gathering of rich data. It brought clarity and understanding to key initiatives discovered in the Montessori lower elementary educational model. The teacher survey, the faculty focus group, and the head of school interviews provided insight into the salient issue of bullying in schools. The findings presents evidence that Montessori serves as a model that is comprehensive. All components of Montessori, when combined, create an environment that succeeds at preventing and addressing bullying in Montessori lower elementary classrooms. The implications of these findings are significant and have the potential to bring great insight to DASA, as a new policy

Expression Levels of Thymidylate Synthase, Thymidylate Phosphorylase and Dihydropyrimidine Dehydrogenase in Head and Neck Squamous Cell Carcinoma: Preliminary Study

Introduction Pharyngo-laryngeal tumors classified as T3-4, N0-3, M0, are conventionally treated by mutilating surgery (total (pharyngo)-laryngectomy). Neo-adjuvant chemotherapy with 5-FU/platinum salt can be proposed in an attempt to preserve the larynx. The level of the response to chemotherapy ranges from 36 to 54% of cases. Thus, a large number of patients receive chemotherapy that is ineffective and not free from adverse effects. Three main enzymes are involved in the metabolism of 5-FU: thymidylate synthase (TS), thymidylate phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD). Several studies suggest that a high level of expression of these three genes correlates with a poor clinical response to 5-FU. The main purpose of our study was to look for a correlation between the levels of expression of the genes for sensitivity to 5-FU (TS, TP, DPD) within the tumor and the clinical response observed after three courses of chemotherapy combining 5-FU/platinum salt in patients presenting with advanced cancer of the pharyngolarynx. Methods This was a prospective genetic study that had required approval from the Ethics Committee. The main assessment criterion was based on the assessment of the clinical response by an ENT panendoscopy and a cervical CT scan, after three courses of chemotherapy. The expression of the genes was determined by quantitative RT-PCR, using total RNA extracted from tumor biopsies taken during the initial panendoscopy. Results The means calculated, in our study, for the three genes of interest (TS, TP, DPD) were lower in the responder group than those in the non-responder group. Discussion Our preliminary findings reveal trends that confirm the hypothesis that the lower the level of expression of the sensitivity genes, the better the clinical response to chemotherapy. They now form part of a larger study that is currently in progress

Episodes of falling among elderly people: a systematic review and meta-analysis of social and demographic pre-disposing characteristics

CONTEXT: The multifactorial nature of falls among elderly people is well-known. Identifying the social-demographic characteristics of elderly people who fall would enable us to define the typical profile of the elderly who are at risk of falling. OBJECTIVE: We aimed to isolate studies in which the social-demographic risk factors for falls among the elderly have been evaluated and to carry out a meta-analysis by combining the results of all of these selected studies. METHOD: We did a systematic literature review using the key words "accidental fall / numerical data" and "risk factors." Inclusion criteria entailed the selection of articles with the following characteristics: population of subjects aged 60 years or over, falls that took place in everyday life, and social-demographic risk factors for falls. RESULTS: 3,747 indexed articles published between 1981 and 2007 were identified, and 177 studies with available data were included, of which 129 had data on social-demographic risk factors for falls. Difficulties in activities of daily living (ADL) or in instrumental activities of daily living (IADL) double the risk of falling: The OR and 95% Cl were 2.26 (2.09, 2.45) for disturbance ADL and 2.10 (1.68, 2.64) for IADL. The OR and 95% Cl for Caucasians were 1.68 (0.98 - 2.88) and 0.64 (0.51 - 0.80) for Hispanics. In the subgroup of patients older than eighty, being married protected people from falling with an OR and 95% Cl =0.68 (0.53 - 0.87). CONCLUSION: Defining factors that create a risk of falling and protect elderly people from falls using social-demographic characteristics lets us focus on an "at risk" population for which a specific program could be developed

Forced oscillations dynamic tribometer with real-time insights of lubricated interfaces

This paper presents an innovative forced oscillations dynamic tribometer, the CHRONOS tribometer, with a lubricated ball-on-flat contact configuration fitted out with an in situ optical visualization system and a triggered high-speed camera. The CHRONOS tribometer generates controlled oscillating kinematics by means of a shaker with a range of strokes from 5 μm to 2.5 mm and an oscillation frequency which can be adjusted from 5 Hz to 250 Hz. Displacement and velocity are measured using a vibrometer. The ball-on-flat mean contact pressure is set between 200 MPa and 600 MPa. During motion, the instantaneous normal and friction forces and the interfacial film thickness distribution (in the nanometer scale) are simultaneously measured. In addition to this instantaneous approach, a more macroscopic approach is developed in terms of moving averages of friction and velocity. Another parameter, the friction-velocity tilt angle, is also introduced. This last parameter may give information on the friction-velocity dependence. Eventually, the experiments performed on the CHRONOS device lead to the representation of synchronized temporal signals of displacement/velocity, friction, and lubricant central film thickness. This superimposition of key parameters reveals time effects introduced by the periodical fluid squeeze and flow in the contact