Data assimilation of Aerosol Robotic Network (AERONET) and Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical thickness (AOT) for aerosol forecasting was tested within the Navy ...Aerosol Analysis Prediction System (NAAPS) framework, using variational and ensemble data assimilation methods. Navy aerosol forecasting currently makes use of a deterministic NAAPS simulation coupled to Navy Variational Data Assimilation System for aerosol optical depth, a two-dimensional variational data assimilation system, for MODIS AOT assimilation. An ensemble version of NAAPS (ENAAPS) coupled to an ensemble adjustment Kalman filter (EAKF) from the Data Assimilation Research Testbed was recently developed, allowing for a range of data assimilation and forecasting experiments to be run with deterministic NAAPS and ENAAPS. The main findings are that the EAKF, with its flow-dependent error covariances, makes better use of sparse observations such as AERONET AOT. Assimilating individual AERONET observations in the two-dimensional variational system can increase the analysis errors when observations are located in high AOT gradient regions. By including AERONET with MODIS AOT assimilation, the magnitudes of peak aerosol events (AOT> 1) were better captured with improved temporal variability, especially in India and Asia where aerosol prediction is a challenge. Assimilating AERONET AOT with MODIS had little impact on the 24 h forecast skill compared to MODIS assimilation only, but differences were found downwind of AERONET sites. The 24 h forecast skill was approximately the same for forecasts initialized with analyses from AERONET AOT assimilation alone compared to MODIS assimilation, particularly in regions where the AERONET network is dense; including the United States and Europe, indicating that AERONET could serve as a backup observation network for over-land synoptic-scale aerosol events.
An ensemble-based forecast and data assimilation system has been developed for use in Navy aerosol forecasting. The system makes use of an ensemble of the Navy Aerosol Analysis Prediction System ...(ENAAPS) at 1 × 1°, combined with an ensemble adjustment Kalman filter from NCAR's Data Assimilation Research Testbed (DART). The base ENAAPS-DART system discussed in this work utilizes the Navy Operational Global Analysis Prediction System (NOGAPS) meteorological ensemble to drive offline NAAPS simulations coupled with the DART ensemble Kalman filter architecture to assimilate bias-corrected MODIS aerosol optical thickness (AOT) retrievals. This work outlines the optimization of the 20-member ensemble system, including consideration of meteorology and source-perturbed ensemble members as well as covariance inflation. Additional tests with 80 meteorological and source members were also performed. An important finding of this work is that an adaptive covariance inflation method, which has not been previously tested for aerosol applications, was found to perform better than a temporally and spatially constant covariance inflation. Problems were identified with the constant inflation in regions with limited observational coverage. The second major finding of this work is that combined meteorology and aerosol source ensembles are superior to either in isolation and that both are necessary to produce a robust system with sufficient spread in the ensemble members as well as realistic correlation fields for spreading observational information. The inclusion of aerosol source ensembles improves correlation fields for large aerosol source regions, such as smoke and dust in Africa, by statistically separating freshly emitted from transported aerosol species. However, the source ensembles have limited efficacy during long-range transport. Conversely, the meteorological ensemble generates sufficient spread at the synoptic scale to enable observational impact through the ensemble data assimilation. The optimized ensemble system was compared to the Navy's current operational aerosol forecasting system, which makes use of NAVDAS-AOD (NRL Atmospheric Variational Data Assimilation System for aerosol optical depth), a 2-D variational data assimilation system. Overall, the two systems had statistically insignificant differences in root-mean-squared error (RMSE), bias, and correlation relative to AERONET-observed AOT. However, the ensemble system is able to better capture sharp gradients in aerosol features compared to the 2DVar system, which has a tendency to smooth out aerosol events. Such skill is not easily observable in bulk metrics. Further, the ENAAPS-DART system will allow for new avenues of model development, such as more efficient lidar and surface station assimilation as well as adaptive source functions. At this early stage of development, the parity with the current variational system is encouraging.
Sea surface temperature retrievals using the Advanced Very High Resolution Radiometer are highly sensitive to cloud cover and coarse mode aerosol particles such as dust. Operationally, techniques are ...used to flag contaminated retrievals; however, these techniques are less precise in removing dust-contaminated values. A commonly stated metric of quality for SST daytime retrievals is 0.5°C; thus dust contents that produce errors greater than this value should be of concern. Here we report on significant correlation between potential SST error and observed aerosol optical depths (AOD) that was found in the tropical region dominated by Saharan dust. Utilizing a radiative transfer model with variable dust contents and typical vertical distributions, errors greater than the desired 0.5°C accuracy are observed for dust AODs as low as 0.05. Errors of over 1°C occur with 0.25 AOD. Analysis of the AERONET data from Cape Verde, which includes the Saharan Air Layer off the west coast of Africa, reveals that 90% of the days during the boreal summer are found to have AOD amounts that correspond to error greater than 0.5°C. We found that a correction accurate within 0.25°C requires a mean accuracy of 0.1 AOD and proper vertical placement of the dust layer within 250m. While empirical SST retrievals often have some measure of climatological dust contamination built into them, this work shows that typical variability in dust loadings is a non-trivial error source against SST retrieval goals.
•We model and observe the sensitivity of airborne dust particles on SST retrievals.•A clear increasing negative bias in SST occurs with increasing AOD.•Seasonality of dust can lead to season and regional biases in SST.•A dust AOD of 0.1 roughly corresponds to an SST error of 0.5°C.•Dust corrections must include the vertical location and temperature of dust layer.
We introduce the concept of constant-gate-charge scaling to increase the short-circuit withstand time of SiC power MOSFETs without increasing their ON-state resistance, gate charge, or oxide field. ...In gate-charge scaling, we scale the oxide thickness and gate drive voltage, keeping the oxide field constant. Short-circuit measurements on 1200 V SiC double-implanted MOSFETs (DMOSFETs) confirm that short-circuit withstand times can be increased by 2-<inline-formula> <tex-math notation="LaTeX">4\times </tex-math></inline-formula> without increasing ON-resistance, simply by reducing the oxide thickness and the gate drive voltage.
Abstract
Passive longwave infrared radiometric satellite–based retrievals of sea surface temperature (SST) at instrument nadir are investigated for cold bias caused by unscreened optically thin ...cirrus (OTC) clouds cloud optical depth (COD) ≤ 0.3. Level 2 nonlinear SST (NLSST) retrievals over tropical oceans (30°S–30°N) from Moderate Resolution Imaging Spectroradiometer (MODIS) radiances collected aboard the NASA
Aqua
satellite (
Aqua
-MODIS) are collocated with cloud profiles from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument. OTC clouds are present in approximately 25% of tropical quality-assured (QA)
Aqua
-MODIS Level 2 data, representing over 99% of all contaminating cirrus found. Cold-biased NLSST (MODIS, AVHRR, and VIIRS) and triple-window (AVHRR and VIIRS only) SST retrievals are modeled based on operational algorithms using radiative transfer model simulations conducted with a hypothetical 1.5-km-thick OTC cloud placed incrementally from 10.0 to 18.0 km above mean sea level for cloud optical depths between 0.0 and 0.3. Corresponding cold bias estimates for each sensor are estimated using relative
Aqua
-MODIS cloud contamination frequencies as a function of cloud-top height and COD (assuming they are consistent across each platform) integrated within each corresponding modeled cold bias matrix. NLSST relative OTC cold biases, for any single observation, range from 0.33° to 0.55°C for the three sensors, with an absolute (bulk mean) bias between 0.09° and 0.14°C. Triple-window retrievals are more resilient, ranging from 0.08° to 0.14°C relative and from 0.02° to 0.04°C absolute. Cold biases are constant across the Pacific and Indian Oceans. Absolute bias is lower over the Atlantic but relative bias is higher, indicating that this issue persists globally.
Objectives
To assess whether the joint effects of water and sanitation infrastructure, are acting antagonistically (redundant services preventing the same cases of diarrhoeal disease), independently, ...or synergistically; and to assess how these effects vary by country and over time.
Methods
We used data from 217 Demographic and Health Surveys conducted in 74 countries between 1986 and 2013. We used modified Poisson regression to assess the impact of water and sanitation infrastructure on the prevalence of diarrhoea among children under 5.
Results
The impact of water and sanitation varied across surveys, and adjusting for socio‐economic status drove these estimates towards the null. Sanitation had a greater effect than water infrastructure when all 217 surveys were pooled; however, the impact of sanitation diminished over time. Based on survey data from the past 10 years, we saw no evidence for benefits in improving drinking water or sanitation alone, but we estimated a 6% reduction of both combined (prevalence ratio = 0.94, 95% confidence limit 0.91–0.98).
Conclusions
Water and sanitation interventions should be combined to maximise the number of cases of diarrhoeal disease prevented in children under 5. Further research should identify the sources of variability seen between countries and across time. These national surveys likely include substantial measurement error in the categorisation of water and sanitation, making it difficult to interpret the roles of other pathways.
Objectifs
Evaluer les effets conjoints des infrastructures de l'eau et d'assainissement afin de voir si elles sont des services redondants prévenant les mêmes cas de maladies diarrhéiques, si elles agissent indépendamment ou en synergie et d’évaluer comment ces effets varient selon les pays et au fil du temps.
Méthodes
Nous avons utilisé les données de 217 enquêtes démographiques et santé menées dans 90 pays entre 1986 et 2013. Nous avons utilisé la régression de Poisson modifiée pour évaluer l'impact des infrastructures de l'eau et d'assainissement sur la prévalence de la diarrhée chez les enfants de moins de cinq ans.
Résultats
L'impact de l'eau et de l'assainissement variait dans toutes les enquêtes et l'ajustement pour le statut socioéconomique conduisait ces estimations vers le néant. L'assainissement avait un effet plus important que l'infrastructure de l'eau lorsque toutes les 217 enquêtes ont été poolées. Toutefois, l'impact de l'assainissement a diminué au fil du temps. Basé sur des données d'enquêtes des dix dernières années, nous n'avons vu aucune preuve pour les bénéfices de l'amélioration de l'eau potable ou de l'assainissement seuls, mais nous avons estimé une réduction de 6% pour la combinaison des deux (rapport de prévalence = 0,94; IC95%: 0,91 à 0,98).
Conclusions
Les interventions sur l'eau et l'assainissement devraient être combinées pour maximiser le nombre de cas de maladies diarrhéiques prévenus chez les enfants de moins de cinq ans. Des recherches supplémentaires devraient identifier les sources de variabilité observées entre les pays et dans le temps. Ces enquêtes nationales comportent probablement une erreur importante de mesure dans la catégorisation de l'eau et de l'assainissement, ce qui rend difficile l'interprétation des rôles des autres voies.
Objetivos
Evaluar el efecto conjunto del agua e infraestructura sanitaria, y determinar si son servicios redundantes que previenen los mismos casos de enfermedad diarreica, actúan de forma independiente o actúan de forma sinérgica; y evaluar como dichos efectos varían según el país y a lo largo del tiempo.
Métodos
Hemos utilizado los datos de 217 Censos Demográficos y de Salud realizados en 90 países entre 1986 y 2013. Hemos realizado una regresión de Poisson modificada para evaluar el impacto del agua y de la infraestructura sanitaria sobre la prevalencia de la diarrea en niños menores de cinco años.
Resultados
El impacto del agua y del saneamiento variaba a lo largo de los censos, y el ajustar según el estatus socioeconómico llevaba los resultados a cero. El saneamiento tenía un mayor efecto que la infraestructura para el agua si se agrupaban los 217 censos; sin embargo, el impacto del saneamiento disminuía a lo largo del tiempo. Basado en los datos censales de los últimos diez años, no encontramos evidencia de los beneficios de la mejora del agua para consumo o del saneamiento por sí solos, pero hemos estimado una reducción del 6% de las dos intervenciones combinadas (tasa de prevalencia = 0.94, IC 95% 0.91‐0.98).
Conclusiones
Las intervenciones en el agua o el saneamiento deberían combinarse para maximizar el número de casos de enfermedad diarréica prevenidas en niños menores de cinco años. Estudios futuros deberían identificar las fuentes de variabilidad observada entre países y a lo largo del tiempo. Es posible que los censos nacionales incluyan un error sustancial en la medición de las categorías de agua y saneamiento, lo cual complica la determinación del papel de vías alternativas.
Approximately 20% of oocytes are classified as immature and discarded following intracytoplasmic sperm injection (ICSI) procedures. These oocytes are obtained from gonadotropin-stimulated patients, ...and are routinely removed from the cumulus cells which normally would mature the oocytes. Given the ready access to these human oocytes, they represent a potential resource for both clinical and basic science application. However culture conditions for the maturation of cumulus-free oocytes have not been optimized. We aimed to improve maturation conditions for cumulus-free oocytes via culture with ovarian paracrine/autocrine factors identified by single cell analysis.
Immature human oocytes were matured in vitro via supplementation with ovarian paracrine/autocrine factors that were selected based on expression of ligands in the cumulus cells and their corresponding receptors in oocytes. Matured oocytes were artificially activated to assess developmental competence. Gene expression profiles of parthenotes were compared to IVF/ICSI embryos at morula and blastocyst stages. Following incubation in medium supplemented with ovarian factors (BDNF, IGF-I, estradiol, GDNF, FGF2 and leptin), a greater percentage of oocytes demonstrated nuclear maturation and subsequently, underwent parthenogenesis relative to control. Similarly, cytoplasmic maturation was also improved as indicated by development to blastocyst stage. Parthenogenic blastocysts exhibited mRNA expression profiles similar to those of blastocysts obtained after IVF/ICSI with the exception for MKLP2 and PEG1.
Human cumulus-free oocytes from hormone-stimulated cycles are capable of developing to blastocysts when cultured with ovarian factor supplementation. Our improved IVM culture conditions may be used for obtaining mature oocytes for clinical purposes and/or for derivation of embryonic stem cells following parthenogenesis or nuclear transfer.
The cannabinoid receptor 1 (CB1) is an inhibitory G protein-coupled receptor abundantly expressed in the central nervous system. It has rich pharmacology and largely accounts for the recreational use ...of cannabis. We describe efficient asymmetric syntheses of four photoswitchable Δ
-tetrahydrocannabinol derivatives (azo-THCs) from a central building block 3-Br-THC. Using electrophysiology and a FRET-based cAMP assay, two compounds are identified as potent CB1 agonists that change their effect upon illumination. As such, azo-THCs enable CB1-mediated optical control of inwardly rectifying potassium channels, as well as adenylyl cyclase.
The LIM-domain-binding protein Ldb1 is a key factor in the assembly of transcriptional complexes involving LIM-homeodomain proteins and other transcription factors that regulate animal development. ...We identified Ssdp proteins (previously described as sequence-specific, single-stranded-DNA-binding proteins) as components of Ldb1-associated nuclear complexes in HeLa cells. Ssdp proteins are associated with Ldb1 in a variety of additional mammalian cell types. This association is specific, does not depend on the presence of nucleic acids, and is functionally significant. Genes encoding Ssdp proteins are well conserved in evolution from Drosophila to humans. Whereas the vertebrate Ssdp gene family has several closely related members, the Drosophila Ssdp gene is unique. In Xenopus, Ssdp encoded by Drosophila Ssdp or mouse Ssdp1 mRNA enhances axis induction by Ldb1 in conjunction with the LIM-homeobox gene Xlim1. Furthermore, we were able to demonstrate an interaction between Ssdp and Chip (the fly homolog of Ldb1) in Drosophila wing development. These findings indicate functional conservation of Ssdp as a cofactor of Ldb1 during invertebrate and vertebrate development.
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