Secondary Education in Sub-Saharan Africa Teacher Preparation Deployment and Support Case study: Senegal

This report is one component of a wide-ranging study on the education of secondary school teachers in sub-Saharan Africa. It informs and provides direct input into the larger study, which culminates in an Overview Report. The Overview Report is one of 13 background papers which contribute to a comprehensive study of secondary education in Africa (SEA) coordinated by the Mastercard Foundation and supported by a number of education partners operating across the continent. Senegal is one of four case studies selected for this research. The study's theoretical framework was developed out of the Literature Review, which also produced a set of research questions that guided the work of all components, including this case study. Data for the case study was derived from academic and other literature, as well as interviews with key role players in the field of teacher education in Rwanda. These role players include government officials responsible for teacher education on a national and/or regional basis, teacher educators responsible for initial teacher education (ITE) and Continuous Professional Development (CPD), and teacher unions. Face-to-face interviews were conducted where possible, but some actors provided information via telephonic or electronic means

Dramatización y argumentación en sociedades orales africanas

African traditional societies are oral societies. Orality, in these societies, is the effect as much as the cause of the particular mode of social being of the African man (Aguessy 1979). An African man is socially configured by orality. It is therefore a cultural formatting whose main issue is preservation and transmission, from age to age, of traditions, social norms and practices that determine the relationship of man of orality with the world. Moreover, according to Diagne (2005), the process by which this cultural formatting, specific to traditional African societies is carried out, is the “dramatization”. Dramatization is the ruse of oral reason (Diagne 2005). The aim of this paper is to grasp, through the process of dramatization, cultural particularities of argumentation in traditional African societies. In order to do so, the analysis focuses on the discursive practices through which dramatization is revealed. More precisely, the study of proverbs in eʋe society allows pointing out the specificities of dramatized argumentation in an oral society. The epistemological issue animating this paper is to present a different way of grasping argumentative functions of image and metaphor.Las sociedades tradicionales africanas son sociedades orales. La oralidad es el efecto tanto como la causa de cierto modo de ser social del hombre africano (Aguessy 1979). Un africano está socialmente configurado por la oralidad. Se trata, pues, de un formato cultural cuyo objetivo es la conservación y la transmisión, de edad en edad, de la tradición de las normas y prácticas sociales que determinan la relación del hombre con la realidad. Y según Diagne (2005) el proceso por el cual este formato cultural específico de las sociedades tradicionales africanas se realiza la «dramatización». La dramatización es la astucia de la razón oral (Diagne 2005). El objetivo de este texto es captar, a través del proceso de dramatización, las particularidades de la argumentación en las sociedades tradicionales africanas. En este sentido, el análisis se centra en las prácticas discursivas por las cuales la dramatización se manifiesta. Más precisamente, el estudio de los proverbios eʋe permite mostrar las especificidades de la argumentación dramatizada en una sociedad oral. El desafío epistemológico será una nueva manera de comprender las funciones argumentales de la imagen y de la metáfora

On the numerical interpretation of gravity and other potential field anomalies caused by layers of varying thickness

This thesis involves the interpretation of gravity and other potential field anomalies caused by layers of varying thickness. The partial differential equations of potential field theory are reviewed for gravitational and magnetic force fields. A similar review is carried out for steady-state heat transport and diffusion processes. For the gravitational force fields, solutions of the partial differential equations are listed in integral form for the following cases: single body with given constant density, infinitely thin sheet with variable mass density, two homogeneous layers with a slowly undulating interface and two layers with a vertically-constant-density lower layer. The solutions give the gravity anomaly in terms of the parameters of the source body. Heat transport phenomena of a similar nature are also discussed. The general expression obtained for the two homogeneous layers with a slowly undulating interface is used as an integral equation and applied to the derivation of crustal thickness variation in Oregon on the basis of two different computational methods. The first method, called the digitized algebraic method, solves the quasi-linearized form of the general integral equation by an iterative technique for three reference va1ues of the mean depth of the crust-mantle interface, viz., 25 km, 30 km, and 35 km. The second approach, called the second derivative approximation method, gives a solution by the Fourier transform technique to the linearized form of the general integral equation for the same three reference values of the mean depth of the crust-mantle interface. The above results as to the depth of the crust-mantle interface are compared with recent results with seismic refraction and dispersion data obtained along a profile in eastern Oregon. The value of the reference depth d which best reconciles with the above results and the seismic results turns out to be 30.25 km for the depth data on the basis of the algebraic method and 28.90 km for the depth data obtained with the second derivative approximation method

TIE-2 Signaling Activation by Angiopoietin 2 On Myeloid-Derived Suppressor Cells Promotes Melanoma-Specific T-cell Inhibition

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immune suppressive cells detected in several human cancers. In this study, we investigated the features and immune suppressive function of a novel subset of monocytic MDSC overexpressing TIE-2 (TIE-2+ M-MDSC), the receptor for the pro-angiogenic factor angiopoietin 2 (ANGPT2). We showed that patients with melanoma exhibited a higher circulating rate of TIE-2+ M-MDSCs, especially in advanced stages, as compared to healthy donors. The distribution of the TIE-2+ M-MDSC rate toward the melanoma stage correlated with the serum level of ANGPT2. TIE-2+ M-MDSC from melanoma patients overexpressed immune suppressive molecules such as PD-L1, CD73, TGF-β, and IL-10, suggesting a highly immunosuppressive phenotype. The exposition of these cells to ANGPT2 increased the expression of most of these molecules, mainly Arginase 1. Hence, we observed a profound impairment of melanoma-specific T-cell responses in patients harboring high levels of TIE-2+ M-MDSC along with ANGPT2. This was confirmed by in vitro experiments indicating that the addition of ANGPT2 increased the ability of TIE-2+ M-MDSC to suppress antitumor T-cell function. Furthermore, by using TIE-2 kinase-specific inhibitors such as regorafenib or rebastinib, we demonstrated that an active TIE-2 signaling was required for optimal suppressive activity of these cells after ANGPT2 exposition. Collectively, these results support that TIE-2+ M-MDSC/ANGPT2 axis represents a potential immune escape mechanism in melanoma

c-Maf enforces cytokine production and promotes memory-like responses in mouse and human type 2 innate lymphoid cells

Group-2 innate lymphoid cells (ILC2s), which are involved in type 2 inflammatory diseases such as allergy, can exhibit immunological memory, but the basis of this ILC2 "trained immunity" has remained unclear. Here, we found that stimulation with IL-33/IL-25 or exposure to the allergen papain induces the expression of the transcription factor c-Maf in mouse ILC2s. Chronic papain exposure results in high production of IL-5 and IL-13 cytokines and lung eosinophil recruitment, effects that are blocked by c-Maf deletion in ILCs. Transcriptomic analysis revealed that knockdown of c-Maf in ILC2s suppresses expression of type 2 cytokine genes, as well as of genes linked to a memory-like phenotype. Consistently, c-Maf was found highly expressed in human adult ILC2s but absent in cord blood and required for cytokine production in isolated human ILC2s. Furthermore, c-Maf-deficient mouse or human ILC2s failed to exhibit strengthened (“trained”) responses upon repeated challenge. Thus, the expression of c-Maf is indispensable for optimal type 2 cytokine production and proper memory-like responses in group-2 innate lymphoid cells

Cancer immunotherapy

Tumor cells are recognized by the immune system, which controls the growth of some immunogenic tumors. Cancer immunotherapy is based on the stimulation of this natural defence against cancer. The use of recombinant cytokines (IL-2, IFN!…) and especially of antibodies has demonstrated the clinical efficacy of this approach. New immunotherapeutic strategies are being developed, based on the induction of anti-tumor T lymphocytes by cancer vaccines. The optimization of these vaccines is based on their validation in relevant preclinical and clinical models (spontaneous tumors in rodents and carnivore), on their association withmolecules able to inhibit the resistancemechanisms of tumours to immunotherapy, and on more clearly defined clinical indications.Des cellules tumorales peuvent être reconnues par le système immunitaire qui contrôle le développement de certaines tumeurs. L'immunothérapie anti-tumorale consiste à stimuler cette immunité naturelle contre les cancers. L'emploi de cytokines recombinantes (IL-2, IFNα...) et surtout d'anticorps a permis de démontrer l'efficacité clinique de cette approche. De nouvelles stratégies d'immunothérapie reposant sur l'induction de lymphocytes T anti-tumoraux par des vaccins sont en cours de développement. L'optimisation de ces vaccins repose sur leur validation dans des modèles cliniques pertinents (tumeurs spontanées des rongeurs et des carnivores), sur leur association à des molécules permettant de lever des mécanismes de résistance de la tumeur à l'immunothérapie et sur des indications cliniques mieux définies de ces vaccins

Comprehensive analysis of current approaches to inhibit regulatory T cells in cancer

CD4+CD25+Foxp3+ regulatory T cells (Treg) have emerged as a dominant T cell population inhibiting anti-tumor effector T cells. Initial strategies used for Treg-depletion (cyclophosphamide, anti-CD25 mAb…) also targeted activated T cells, as they share many phenotypic markers. Current, ameliorated approaches to inhibit Treg aim to either block their function or their migration to lymph nodes and the tumor microenvironment. Various drugs originally developed for other therapeutic indications (anti-angiogenic molecules, tyrosine kinase inhibitors,etc) have recently been discovered to inhibit Treg. These approaches are expected to be rapidly translated to clinical applications for therapeutic use in combination with immunomodulators

Targeting the tumor vasculature to enhance T cell activity.

T cells play a critical role in tumor immune surveillance as evidenced by extensive mouse-tumor model studies as well as encouraging patient responses to adoptive T cell therapies and dendritic cell vaccines. It is well established that the interplay of tumor cells with their local cellular environment can trigger events that are immunoinhibitory to T cells. More recently it is emerging that the tumor vasculature itself constitutes an important barrier to T cells. Endothelial cells lining the vessels can suppress T cell activity, target them for destruction, and block them from gaining entry into the tumor in the first place through the deregulation of adhesion molecules. Here we review approaches to break this tumor endothelial barrier and enhance T cell activity

Tyrosine kinase inhibitors reprogramming immunity in renal cell carcinoma: rethinking cancer immunotherapy

Review article[Abstract] The immune system regulates angiogenesis in cancer by way of both pro- and antiangiogenic activities. A bidirectional link between angiogenesis and the immune system has been clearly demonstrated. Most antiangiogenic molecules do not inhibit only VEGF signaling pathways but also other pathways which may affect immune system. Understanding of the role of these pathways in the regulation of immunosuppressive mechanisms by way of specific inhibitors is growing. Renal cell carcinoma (RCC) is an immunogenic tumor in which angiogenesis and immunosuppression work hand in hand, and its growth is associated with impaired antitumor immunity. Given the antitumor activity of selected TKIs in metastatic RCC (mRCC), it seems relevant to assess their effect on the immune system. The confirmation that TKIs improve cell cytokine response in mRCC provides a basis for the rational combination and sequential treatment of TKIs and immunotherapy

AB Toxins: A Paradigm Switch from Deadly to Desirable

To ensure their survival, a number of bacterial and plant species have evolved a common strategy to capture energy from other biological systems. Being imperfect pathogens, organisms synthesizing multi-subunit AB toxins are responsible for the mortality of millions of people and animals annually. Vaccination against these organisms and their toxins has proved rather ineffective in providing long-term protection from disease. In response to the debilitating effects of AB toxins on epithelial cells of the digestive mucosa, mechanisms underlying toxin immunomodulation of immune responses have become the focus of increasing experimentation. The results of these studies reveal that AB toxins may have a beneficial application as adjuvants for the enhancement of immune protection against infection and autoimmunity. Here, we examine similarities and differences in the structure and function of bacterial and plant AB toxins that underlie their toxicity and their exceptional properties as immunomodulators for stimulating immune responses against infectious disease and for immune suppression of organ-specific autoimmunity