Photo-desorption of H2O:CO:NH3 circumstellar ice analogs: Gas-phase enrichment

We study the photo-desorption occurring in H$_2$O:CO:NH$_3$ ice mixtures irradiated with monochromatic (550 and 900 eV) and broad band (250--1250 eV) soft X-rays generated at the National Synchrotron Radiation Research Center (Hsinchu, Taiwan). We detect many masses photo-desorbing, from atomic hydrogen (m/z = 1) to complex species with m/z = 69 (e.g., C$_3$H$_3$NO, C$_4$H$_5$O, C$_4$H$_7$N), supporting the enrichment of the gas phase. At low number of absorbed photons, substrate-mediated exciton-promoted desorption dominates the photo-desorption yield inducing the release of weakly bound (to the surface of the ice) species; as the number of weakly bound species declines, the photo-desorption yield decrease about one order of magnitude, until porosity effects, reducing the surface/volume ratio, produce a further drop of the yield. We derive an upper limit to the CO photo-desorption yield, that in our experiments varies from 1.4 to 0.007 molecule photon$^{-1}$ in the range $\sim 10^{15} - 10^{20}$~absorbed photons cm$^{-2}$. We apply these findings to a protoplanetary disk model irradiated by a central T~Tauri star

Modelling of reservoir network for flood control using nonlinear reservoir routing model

Network of reservoirs has become a standard hydraulic construct for multipurpose use. In this work, we present a formulation based on nonlinear reservoir method and coupled tank approach to model the reservoir network for flood control. The network of reservoirs consists of both detention and retention pond which give rise to nonlinear system of ODE for the m reservoirs in the network. The inflow consists of rainfall runoff in each sub catchment and discharges from the adjacent reservoirs. On the other hands, the outflow consists of infiltration and discharges. The nonlinear system obtained is linearized about the normal operating height of each reservoir in the network. The discharge term on the last equation is dropped in order to allow all the runoff captured into it. The establishment of relationship between the area of catchment and area of reservoir give room for the estimation of the forcing function in terms time of concentration rather than in terms of area of the reservoir which is difficult to obtain in an existing network. Two sets of solutions are presented, one at the convergent point and the other the best solution in respect of the lowest point in the reservoirs

Influence de l’acide salicylique sur l’activité des polyphénoloxydases et l’accumulation des composés phénoliques chez le manioc (Manihot esculenta Crantz )

Influence of salicylic acid on activity of polyphenol oxidases and accumulation of phenolic compounds in cassava (Manihot esculenta Crantz)To study the reaction of defence of cassava, we have measured the activity of polyphenol oxidases (PPO) and dosed total ethano-soluble phenolic compounds accumulated before and after inoculation of salicylic acid in six weeks old seedlings. PPO activity has beenprecociously induced (1 h) for the cultivars bouaga, mamawa, tapioca and ecrevisse but tardily for the cultivars bonoua (4 h) and yace (12 h). PPO have been 3 to 11.50 times stimulated according to varieties.Dosed total phenolic compounds have undergone a significant increase since the inoculation, and this rate has remained almost constant during experimentation. The synthesis of enzyme has been equally stimulated in immediately situated leaves above (fis) and in under (fii) of the inoculated leaf (fi). Phenolic compound have also undergonean increase in these leaves. Concerning the age of the inoculated leaf (4 and 6 weeks), PPO activity and the phenolic compounds quantity have become more important in adult leaves

Challenges and achievements in the utilization of the health system among adolescents in a region of Burkina Faso particularly affected by poverty

Objective: Healthcare for adolescents receives little attention in low-income countries globally despite their large population share in these settings, the importance of disease prevention at these ages for later life outcomes and adolescent health needs differing from those of other ages. We therefore examined healthcare need and use among adolescents in rural Burkina Faso to identify reasons for use and gaps in provision and uptake. Methods: We interviewed 1,644 adolescents aged 12-20 living in rural northwestern Burkina Faso in 2017. Topics included healthcare need and satisfaction with care provided. We calculated response-weighted prevalence of perceived healthcare need and utilization, then conducted multivariable regression to look at predictors of need, realized access and successful utilization based on the Andersen and Aday model. Results: 43.7 [41.2 - 46.0] % of participants perceived need for healthcare at least once in the preceding 12 months - 52.0 [48.1 - 56.0] % of females and 35.6 [32.5 - 39.0] % of males. Of those with perceived need, 92.6 [90.0 - 94.3] % were able to access care and 79.0 [75.6 - 82.0] % obtained successful utilization. Need was most strongly predicted by gender, education and urbanicity, while predictors of successful use included household wealth and female guardian’s educational attainment. Conclusion: Healthcare utilization among adolescents is low in rural Burkina Faso, but mostly thought of as sufficient with very few individuals reporting need that was not linked to care. Future objective assessment of healthcare need could help identify whether our results reflect a well-functioning system for these adolescents, or one where barriers lead to low awareness of needs or low expectations for service provision

Influence de l\'acide salicylique sur la synthèse de la phénylalanine ammonia-lyase, des polyphénoloxydases et l\'accumulation des composes phénoliques chez le manioc (Manihot esculenta Crantz)

Pour étudier la réaction de défense du manioc contre les agents pathogènes, nous avons évalué l'activité de la phénylalanine ammonia-lyase (PAL) et des polyphénoloxydases (PPO), et dosé les composés phénoliques totaux éthano-solubles accumulés avant et après l'inoculation de l'acide salicylique (AS) dans des plants âgés de six semaines. La synthèse des enzymes a été précocement induite (1-4 h). L'activité de la PAL a été 4 à 13 fois stimulée et celle des PPO, 3 à 11 fois plus, selon les cultivars. Les taux de composés phénoliques totaux éthano-solubles ont subi une augmentation significative dès l'inoculation des plantes. Ces taux sont restés quasi constants malgré la baisse de l'activité de la PAL. La synthèse de l'enzyme a été également stimulée dans les feuilles immédiatement situées audessus (fis) et en dessous (fii) de la feuille inoculée (fi). Les composés phénoliques ont subi aussi une augmentation dans ces feuilles. Concernant l'âge de la feuille inoculée (4 et 6 semaines), la synthèse de la PAL et la quantité des composés phénoliques ont été plus élevées dans les feuilles adultes.To study the reaction of defence of cassava against pathogens, we have evaluated the activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidases (PPO) and dosed total ethano-soluble phenolic compounds accumulated before and after inoculation of salicylic acid in six weeks old seedlings. Enzymes synthesis was precociously induced (1–4 h). PAL activity was 4 to 13 times stimulated and those PPO, 3 to 11 fold higher, according to varieties. Dosed total phenolic compounds undergone a significant increase since the plants inoculation, and this rate has remained almost constant despite the decrease of PAL activity. The enzyme synthesis was equally stimulated in immediately situated leaves above (fis) and in under (fii) of the inoculated leaf (fi). Phenolic compounds have also undergone an increase in these leaves. Concerning the age of the inoculated leaf (4 and 6 weeks), the PAL synthesis and the phenolic compounds quantity have become more important in adult leaves. Keywords: cassava, phenolic compounds, PAL, PPO, salicylic acid, reaction of defence Sciences & Nature Vol. 5 (1) 2008: pp. 1-1

Growth factors for clinical-scale expansion of human articular chondrocytes : Relevance for automated bioreactor systems

The expansion of chondrocytes in automated bioreactors for clinical use requires that a relevant number of cells be generated, starting from variable initial seeding densities in one passage and using autologous serum. We investigated whether the growth factor combination transforming growth factor beta 1/fibroblast growth factor 2/platelet-derived growth factor BB (TFP), recently shown to enhance the proliferation capacity of human articular chondrocytes (HACs), allows the efficiency of chondrocyte use to be increased at different seeding densities and percentages of human serum (HS). HACs were seeded at 1,000, 5,000, and 10,000 celIS/cm(2) in medium containing 10 bovine serum or 10,000 cells/cm(2) with 1 chondrogenic capacity of post-expanded HACs was then assessed in pellet cultures. Expansion with TFP allowed a sufficient number of HACs to be obtained in one passage even at the lowest seeding density and HS percentage and variability in cartilage-forming capacity of HACs expanded under the different conditions to be reduced. Instead, larger variations and insufficient yields were found in the absence of TFP. By allowing large numbers of cells to be obtained, starting from a wide range of initial seeding densities and HS percentages, the use of TFP may represent a viable solution for the efficient expansion of HACs and addresses constraints of automated clinical bioreactor systems

Phonoritons as Hybridized Exciton-Photon-Phonon Excitations in a Monolayer h -BN Optical Cavity

A phonoriton is an elementary excitation that is predicted to emerge from hybridization between exciton, phonon, and photon. Besides the intriguing many-particle structure, phonoritons are of interest as they could serve as functional nodes in devices that utilize electronic, phononic, and photonic elements for energy conversion and thermal transport applications. Although phonoritons are predicted to emerge in an excitonic medium under intense electromagnetic wave irradiation, the stringent condition for their existence has eluded direct observation in solids. In particular, on-resonance, intense pumping schemes have been proposed, but excessive photoexcitation of carriers prevents optical detection. Here, we theoretically predict the appearance of phonoritonic features in monolayer hexagonal boron nitride (h-BN) embedded in an optical cavity. The coherent superposition nature of phonoriton states is evidenced by the hybridization of exciton-polariton branches with phonon replicas that is tunable by the cavity-matter coupling strength. This finding simultaneously provides an experimental pathway for observing the predicted phonoritons and opens a new avenue for tuning materials properties