The interest rates and performance of MFIs in the MENA region: is there a moral issue?

Full Text / Article completThe high interest rates of microfinance institutions (MFIs) seem to oppose their social mission, and raise a moral issue. We analyse the determinants of the level of interest rates with regard to the financial performance of an unbalanced panel of 66 MFIs in nine countries of the Middle East and North Africa (MENA) region over the period 2004-2012. We differentiate internal factors (cost of capital, operating expenses and loss provisions) from the external ones (regulation, competition and inflation).The outcomes of a typology from a multivariate analysis upon the relationship between the interest rate and social performance of 53 MFIs in 2008 do not match the classification of MFIs according to Yunus and Weber, which proves irrelevant.Le taux d’intérêt élevé des institutions de microfinance (IMF) semble s’opposer à la mission sociale du microcrédit. Nous analysons les déterminants des niveaux des taux d’intérêt au regard de la performance financière d’un panel incomplet de 66 IMF dans 9 pays de la région du Moyen-Orient et d’Afrique du Nord (MENA) sur la période 2004-2012. Nous distinguons les facteurs internes (coût des fonds propres, charges d’exploitation, provisions pour pertes) et externes (règlementation, concurrence et inflation). Nous confrontons la typologie d’une analyse factorielle sur la relation entre taux d’intérêt et performance sociale de 53 IMF de la région en 2008 au classement des IMF selon Yunus & Weber, dont le critère de la marge financière s’avère non pertinent

LES FACTEURS DÉTERMINANTS DE LA PERFORMANCE SOCIALE ET DE LA PERFORMANCE FINANCIÈRE DES INSTITUTIONS DE MICROFINANCE DANS LA RÉGION MENA : UNE ANALYSE EN COUPE INSTANTANÉE

La microfinance se développe progressivement dans la région du Moyen-Orient et d’Afrique du Nord (MENA) à travers des institutions de microfinance (IMF) très variées. L’objectif de la plupart de ces IMF est de concilier la performance sociale (PS) qui vise à réduire la pauvreté et la performance financière (PF) qui vise à assurer une rentabilité pérenne. Y a t-il arbitrage ou compatibilité entre ces deux types de performances ? Une analyse factorielle en coupe instantanée sur un échantillon de 51 IMF dans 9 pays de la région MENA examine la relation entre ces deux performances. Il n’y a pas d’arbitrage pour certaines IMF qui conjuguent les deux performances, dont les facteurs déterminants varient notamment selon le statut (ONG vs non ONG), la maturité, la méthodologie de prêt (solidaire vs individuel), la zone d’interven-tion (rurale vs urbaine), le niveau de transparence informationnelle, la locali-sation géographique et la réglementation des pays dans lesquels œuvrent ces IMF. Abstract - Microfinance is gradually developing in the Middle East and North Africa (MENA) region through a variety of microfinance institutions (MFIs), and the goal of most of these institutions is to achieve the best performance, which can be reached once an MFI is able to reconcile its social performance (SP), by reducing poverty, and its financial performance (FP), by trying to be profitable and sustainable. 1s there a trade-off between these two performances or are they compatible? Following a cross-section factor analysis, we examine the relationship between SP and FP on a sample of 51 MFIs in 9 selected countries of the MENA region: There is no trade-off for some MFIs, which achieve both performances; the determinants vary according to the status (NGO vs. non NGO), maturity, credit methodology (collective vs. individual), intervention areas (rural vs. urban), level of information disclosure, location and regulations of the countries wherein MFIs operate.INSTITUTIONS DE MICROFINANCE, MENA, PAUVRETÉ, PERFORMANCE FINANCIÈRE, PERFORMANCE SOCIALE

Tamm plasmon Photonic Crystals : from Bandgap Engineering to Defect Cavity

We report for the first time the bandgap engineering of Tamm plasmon photonic crystals - Tamm plasmon structures of which the metalic layer is periodically patterned into lattice of subwavelength period. By adopting a double period design, we evidenced experimentally a complete photonic bandgap up to $150\,nm$ in the telecom range. Moreover, such design offers a great flexibility to tailor on-demand, and independently, the band-gap size from $30\,nm$ to $150\,nm$ and its spectral position within $50\,nm$. Finally, by implementing a defect cavity within the Tamm plasmon photonic crystal, an ultimate cavity of $1.6\mu m$ supporting a single highly confined Tamm mode is experimentally demonstrated. All experimental results are in perfect agreement with numerical calculations. Our results suggests the possibility to engineer novel band dispersion with surface modes of hybrid metalic/dielectric structures, thus open the way to Tamm plasmon towards applications in topological photonics, metamaterials and parity symmetry physics

Total IgE and eotaxin (CCL11) contents in tears of patients suffering from seasonal allergic conjunctivitis.

BACKGROUND: To prospectively investigate patients with seasonal allergic conjunctivitis (SAC) during the pollen season and test associations between tears total IgE, eotaxin concentrations, and SAC severity. METHODS: Enrolled patients presented ocular symptoms and clinical signs of SAC at the time of presentation. Ocular itching, hyperaemia, chemosis, eyelid swelling, and tearing were scored, and the sum of these scores was defined as the clinical score. Conjunctival papillae were separately graded. We measured eotaxin concentration in tears by an enzyme-linked immunosorbent assay (ELISA) and total tear IgE by Lacrytest strip. RESULTS: Among thirty patients (30 eyes), 11 showed neither tear IgE nor tear eotaxin, while 15 out of 19 patients with positive IgE values presented a positive amount of eotaxin in their tears (Fisher's test: p < 0.001). The mean eotaxin concentration was 641 ± 154 (SEM) pg/ml. In patients with no amount of tear IgE, we observed a lower conjunctival papilla grade than in patients whose tears contained some amount of IgE (trend test: p = 0.032). In the 15 patients whose tear eotaxin concentration was null, tear IgE concentration was 5.3 ± 3.5 arbitrary units; in the other 15 patients whose eotaxin was positive, IgE reached 21 ± 4.3 arbitrary U (Mann-Whitney: p < 0.001). We measured 127 ± 47 pg/ml eotaxin in patients with no history of SAC but newly diagnosed as suffering from SAC, and 852 ± 218 pg/ml eotaxin in patients with a known SAC (p = 0.008). In contrast, tear IgE concentrations of both groups did not differ statistically significantly (p = 0.947). CONCLUSIONS: If IgE and eotaxin secreted in tears are major contributors in SAC pathogenesis, they however act at different steps of the process

Super Bound States in the Continuum on Photonic Flatbands: Concept, Experimental Realization, and Optical Trapping Demonstration

In this work, we theoretically propose and experimentally demonstrate the formation of a super bound state in a continuum (BIC) on a photonic crystal flat band. This unique state simultaneously exhibits an enhanced quality factor and near-zero group velocity across an extended region of the Brillouin zone. It is achieved at the topological transition when a symmetry-protected BIC pinned at $k=0$ merges with two Friedrich-Wintgen quasi-BICs, which arise from destructive interference between lossy photonic modes of opposite symmetries. As a proof-of-concept, we employ the super flat BIC to demonstrate three-dimensional optical trapping of individual particles. Our findings present a novel approach to engineering both the real and imaginary components of photonic states on a subwavelength scale for innovative optoelectronic devices

Reconfigurable Flat Optics with Programmable Reflection Amplitude Using Lithography-Free Phase-Change Materials Ultra Thin Films

We experimentally demonstrate a very large dynamic optical reflection modulation from a simple unpatterned layered stack of phase-change materials ultrathin films. Specifically, we theoretically and experimentally demonstrate that properly designed deeply subwavelength GeSbTe (GST) films on a metallic mirror produce a dynamic modulation of light in the near-infrared from very strong reflection (R>80%) to perfect absorption (A > 99,97%) by simply switching the crystalline state of the phase-change material. While the amplitude of modulation can lead to an optical contrast up to 10^6, we can also actively "write" intermediate levels of reflection in between extreme values, corresponding to partial crystallization of the GST layer. We further explore several layered system designs and provide guidelines to tailor the wavelength efficiency range, the angle of operation and the degree of crystallization leading to perfect absorption

Total IgE and eotaxin (CCL11) contents in tears of patients suffering from seasonal allergic conjunctivitis

Background: To prospectively investigate patients with seasonal allergic conjunctivitis (SAC) during the pollen season and test associations between tears total IgE, eotaxin concentrations, and SAC severity. Methods: Enrolled patients presented ocular symptoms and clinical signs of SAC at the time of presentation. Ocular itching, hyperaemia, chemosis, eyelid swelling, and tearing were scored, and the sum of these scores was defined as the clinical score. Conjunctival papillae were separately graded. We measured eotaxin concentration in tears by an enzyme-linked immunosorbent assay (ELISA) and total tear IgE by Lacrytest strip. Results: Among thirty patients (30 eyes), 11 showed neither tear IgE nor tear eotaxin, while 15 out of 19 patients with positive IgE values presented a positive amount of eotaxin in their tears (Fisher's test: p < 0.001). The mean eotaxin concentration was 641 ± 154 (SEM) pg/ml. In patients with no amount of tear IgE, we observed a lower conjunctival papilla grade than in patients whose tears contained some amount of IgE (trend test: p = 0.032). In the 15 patients whose tear eotaxin concentration was null, tear IgE concentration was 5.3 ± 3.5 arbitrary units; in the other 15 patients whose eotaxin was positive, IgE reached 21 ± 4.3 arbitrary U (Mann-Whitney: p < 0.001). We measured 127 ± 47pg/ml eotaxin in patients with no history of SAC but newly diagnosed as suffering from SAC, and 852 ± 218pg/ml eotaxin in patients with a known SAC (p = 0.008). In contrast, tear IgE concentrations of both groups did not differ statistically significantly (p = 0.947). Conclusions: If IgE and eotaxin secreted in tears are major contributors in SAC pathogenesis, they however act at different steps of the process

Reversible single-pulse laser-induced phase change of Sb2_2S3_3 thin films: multi-physics modeling and experimental demonstrations

Phase change materials (PCMs) have gained a tremendous interest as a means to actively tune nanophotonic devices through the large optical modulation produced by their amorphous to crystalline reversible transition. Recently, materials such as Sb$_2$S$_3$ emerged as particularly promising low loss PCMs, with both large refractive index modulations and transparency in the visible and NIR. Controlling the local and reversible phase transition in this material is of major importance for future applications, and an appealing method to do so is to exploit pulsed lasers. Yet, the physics and limits involved in the optical switching of Sb$_2$S$_3$ are not yet well understood. Here, we investigate the reversible laser-induced phase transition of Sb$_2$S$_3$, focusing specifically on the mechanisms that drive the optically induced amorphization, with multi-physics considerations including the optical and thermal properties of the PCM and its environment. We theoretically and experimentally determine the laser energy threshold for reversibly changing the phase of the PCM, not only between fully amorphous and crystalline states but also between partially recrystallized states. We then reveal the non-negligible impact of the material's polycrystallinity and anisotropy on the power thresholds for optical switching. Finally, we address the challenges related to laser amorphization of thick Sb$_2$S$_3$ layers, as well as strategies to overcome them. These results enable a qualitative and quantitative understanding of the physics behind the optically-induced reversible change of phase in Sb$_2$S$_3$ layers