T. A. C. M. Ackermann, M. Ajello, A. Albert
et al.
The γ-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse γ-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission (DGE), and a longer data accumulation of 50 months allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of 2.32 ± 0.02 and a break energy of (279 ± 52) GeV using our baseline DGE model. The total intensity attributed to the IGRB is (7.2 ± 0.6) × 10−6 cm−2 s−1 sr−1 above 100 MeV, with an additional +15%/−30% systematic uncertainty due to the Galactic diffuse foregrounds.
BackgroundEthiopia has been implementing a community health extension program (HEP) since 2003. We aimed to assess the successes and challenges of the HEP over time, and develop a framework that may assist the implementation of the program toward universal primary healthcare services.MethodsWe conducted a systematic review and synthesis of the literature on the HEP in Ethiopia between 2003 and 2018. Literature search was accomplished in PubMed, Embase and Google scholar databases. Literature search strategies were developed using medical subject headings (MeSH) and text words related to the aim of the review. We used a three-stage screening process to select the publications. Data extraction was conducted by three reviewers using pre-prepared data extraction form. We conducted an interpretive (not aggregative) synthesis of studies.FindingsThe HEP enabled Ethiopia to achieve significant improvements in maternal and child health, communicable diseases, hygiene and sanitation, knowledge and health care seeking. The HEP has been a learning organization that adapts itself to community demands. The program is also dynamic enough to shift tasks between health centers and community. The community has been a key player in the successful implementation of the HEP. In spite of these successes, the program is currently facing challenges that remain to be addressed. These challenges are related to productivity and efficiency of health extension workers (HEWs); working and living conditions of HEWs; capacity of health posts; and, social determinants of health. These require a systemic approach that involves the wider health system, community, and sectors responsible for social determinants of health. We developed a framework that may assist in the implementation of the HEP.ConclusionThe HEP has enabled Ethiopia to achieve significant improvements. However, several challenges remain to be addressed. The framework can be utilized to improve community health programs toward universal coverage for primary healthcare services.
M. Pineda, Esperanza Fernández, D. Torrents
et al.
We have identified a new human cDNA, L-amino acid transporter-2 (LAT-2), that induces a system L transport activity with 4F2hc (the heavy chain of the surface antigen 4F2, also named CD98) in oocytes. Human LAT-2 is the fourth member of the family of amino acid transporters that are subunits of 4F2hc. The amino acid transport activity induced by the co-expression of 4F2hc and LAT-2 was sodium-independent and showed broad specificity for small and large zwitterionic amino acids, as well as bulky analogs (e.g. BCH (2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid)). This transport activity was highlytrans-stimulated, suggesting an exchanger mechanism of transport. Expression of tagged N-myc-LAT-2 alone in oocytes did not induce amino acid transport, and the protein had an intracellular location. Co-expression of N-myc-LAT-2 and 4F2hc gave amino acid transport induction and expression of N-myc-LAT-2 at the plasma membrane of the oocytes. These data suggest that LAT-2 is an additional member of the family of 4F2 light chain subunits, which associates with 4F2hc to express a system L transport activity with broad specificity for zwitterionic amino acids. Human LAT-2 mRNA is expressed in kidney >>> placenta ≫ brain, liver > spleen, skeletal muscle, heart, small intestine, and lung. Human LAT-2 gene localizes at chromosome 14q11.2–13 (13 cR or ∼286 kb from marker D14S1349). The high expression of LAT-2 mRNA in epithelial cells of proximal tubules, the basolateral location of 4F2hc in these cells, and the amino acid transport activity of LAT-2 suggest that this transporter contributes to the renal reabsorption of neutral amino acids in the basolateral domain of epithelial proximal tubule cells.