27 research outputs found

    Progress in the Development of Practical Remote Detection of Icing Conditions

    Get PDF
    The NASA Icing Remote Sensing System (NIRSS) has been under definition and development at NASA Glenn Research Center since 1997. The goal of this development activity is to produce and demonstrate the required sensing and data processing technologies required to accurately remotely detect and measure icing conditions aloft. As part of that effort NASA has teamed with NCAR to develop software to fuse data from multiple instruments into a single detected icing condition product. The multiple instrument approach utilizes a X-band vertical staring radar, a multifrequency microwave, and a lidar ceilometer. The radar data determine cloud boundaries, the radiometer determines the sub-freezing temperature heights and total liquid water content, and the ceilometer refines the lower cloud boundary. Data is post-processed with a LabVIEW program with a resultant supercooled liquid water profile and aircraft hazard depiction. Ground-based, remotely-sensed measurements and in-situ measurements from research aircraft were gathered during the international 2003-2004 Alliance Icing Research Study (AIRS II). Comparisons between the remote sensing system s fused icing product and the aircraft measurements are reviewed here. While there are areas where improvement can be made, the cases examined suggest that the fused sensor remote sensing technique appears to be a valid approach

    Genetic and environmental effects on crop development determining adaptation and yield

    Get PDF
    Slafer, Gustavo Ariel. ICREA - AGROTECNIO - Spain.Kantolic, Adriana Graciela. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Appendino, María Laura. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Tranquilli, Gabriela Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Recursos Naturales. Instituto de Recursos Biológicos. Buenos Aires, Argentina.Miralles, Daniel Julio. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Savin, Roxana. ICREA - AGROTECNIO - Spain.Crop development is a sequence of phenological events controlled by the genetic background and influenced by external factors, which determines changes in the morphology and/or function of organs (Landsberg, 1977). Although development is a continuous process, the ontogeny of a crop is frequently divided into discrete periods, for instance ‘vegetative’, ‘reproductive’ and ‘grain - filling’ phases (Slafer, 2012). Patterns of phenological development largely determine the adaptation of a crop to a certain range of environments. For example, genetic improvement in grain yield of wheat has been associated with shorter time from sowing to anthesis in Mediterranean environments of western Australia (Siddique et al., 1989), whereas no consistent trends in phenology were found where drought is present but not necessarily terminal, including environments of Argentina, Canada and the USA (Slafer and Andrade, 1989, 1993; Slafer et al., 1994a) (Fig. 12.1). Even in agricultural lands of the Mediterranean Basin where wheat has been grown for many centuries, breeding during the last century did not clearly change phenological patterns (Acreche et al., 2008). This chapter focuses on two major morphologically and hysiologically contrasting grain crops: wheat and soybean. For both species, we have an advanced understanding of development and physiology in general. Wheat is a determinate, long-day grass of temperate origin, which is responsive to vernalization. Soybean is a typically indeterminate (but with determinate intermediate variants), short-day grain legume of tropical origin, which is insensitive to vernalization. Comparisons with other species are used to highlight the similarities and differences. The aims of this chapter are to outline the developmental characteristics of grain crops and the links between phenology and yield, to revise the mechanisms of environmental and genetic control of development and to explore the possibilities of improving crop adaptation and yield potential through the fine-tuning of developmental patterns

    Immunomodulatory strategies prevent the development of autoimmune emphysema

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The presence of anti-endothelial cell antibodies and pathogenic T cells may reflect an autoimmune component in the pathogenesis of emphysema. Whether immune modulatory strategies can protect against the development of emphysema is not known.</p> <p>Methods</p> <p>Sprague Dawley rats were immunized with human umbilical vein endothelial cells (HUVEC) to induce autoimmune emphysema and treated with intrathymic HUVEC-injection and pristane. Measurements of alveolar airspace enlargement, cytokine levels, immuno histochemical, western blot analysis, and T cell repertoire of the lung tissue were performed.</p> <p>Results</p> <p>The immunomodulatory strategies protected lungs against cell death as demonstrated by reduced numbers of TUNEL and active caspase-3 positive cells and reduced levels of active caspase-3, when compared with lungs from HUVEC-immunized rats. Immunomodulatory strategies also suppressed anti-endothelial antibody production and preserved CNTF, IL-1alpha and VEGF levels. The immune deviation effects of the intrathymic HUVEC-injection were associated with an expansion of CD4+CD25+Foxp3+ regulatory T cells. Pristane treatment decreased the proportion of T cells expressing receptor beta-chain, Vβ16.1 in the lung tissue.</p> <p>Conclusions</p> <p>Our data demonstrate that interventions classically employed to induce central T cell tolerance (thymic inoculation of antigen) or to activate innate immune responses (pristane treatment) can prevent the development of autoimmune emphysema.</p

    An experimental investigation of the heat and mass transfer of graupel

    No full text
    The heat and mass transfer of graupel growing in a simulated cloud environment has been investigated experimentally. Rigidly suspended graupel were grown in a wind tunnel airstream under liquid water contents from 0.5 to 3.0 g m-3, velocities from 1.1 to 3.0 m s-1 ambient temperatures from -4.4 to - 20.9°C, cloud droplet median volume radii from 12 to 21 μm and ambient pressures from 100 to 60 kPa. Measurements of the mass, volume, growth height, geometric shape and surface temperature with time were used to calculate the bulk collision efficiency, Nusselt and Sherwood numbers and accretion density. The Lulk collision efficiency and Nusselt number were parametrized in terms of the Stokes parameter and Reynolds number respectively. The density and cone angle were parametrized in terms of the relative graupel-air stream velocity, the cloud droplet median volume radius and the surface temperature. The surface temperature measurements were made remotely with an infrared radiometer to within ± 0.2·c, and represent the first measurements of the surface temperature of growing graupel. The bulk collision efficiency was found to be approximately 30% lower than that for ideal spheres as calculated by Langmuir and Blodgett (1946). The Nusselt number was found to be approximately 50% higher than that for smooth cones. The enhanced heat convection and mass deposition or sublimation is attributed to the roughness of the ice surface. Densities ranged between 0.16 and 0.70 g cm-3 and were between 10 and 30% bwer than those predicted by Heymsfield and Pflaum (1983) for densities lower than 0.4 g cm-3 . The parametrizations of density, cone angle, Nusselt number and bulk collision efficiency represent complete solutions to the heat and mass transfer equations for graupel. Hence the graupel stage of the cold rain process can be fully and accurately incorporated into cloud dynamical models. Such a complete numerical description has not been previously reported.Ph.D

    Retrieval of Cloud Properties and Direct Testing of Cloud and Radiation Parameterizations Using ARM Observations

    No full text
    The problems addressed by this work include cloud optical depth retrieval from satellite and surface data and 3D radiative transfer in dynamical models

    Targeting extracellular vesicle delivery to the lungs by microgel encapsulation

    No full text
    Abstract Extracellular vesicles (EVs) secreted by stem and progenitor cells have significant potential as cell‐free ‘cellular’ therapeutics. Yet, small EVs (<200 nm) are rapidly cleared after systemic administration, mainly by the liver, presenting challenges targeting EVs to a specific organ or tissue. Microencapsulation using natural nano‐porous hydrogels (microgels) has been shown to enhance engraftment and increase the survival of transplanted cells. We sought to encapsulate EVs within microgels to target their delivery to the lung by virtue of their size‐based retention within the pulmonary microcirculation. Mesenchymal stromal cell (MSC) derived EVs were labelled with the lipophilic dye (DiR) and encapsulated within agarose‐gelatin microgels. Endothelial cells and bone marrow derived macrophages were able to take up EVs encapsulated in microgels in vitro, but less efficiently than the uptake of free EVs. Following intrajugular administration, microgel encapsulated EVs were selectively retained within the lungs for 72h, while free EVs were rapidly cleared by the liver. Furthermore, microgel‐loaded EVs demonstrated greater uptake by lung cells, in particular CD45+ immune cells, as assessed by flow cytometry compared to free EVs. Microencapsulation of EVs may be a novel tool for enhancing the targeted delivery of EVs for future therapeutic applications

    Single-cell transcriptomic atlas of lung microvascular regeneration after targeted endothelial cell ablation

    No full text
    We sought to define the mechanism underlying lung microvascular regeneration in a model of severe acute lung injury (ALI) induced by selective lung endothelial cell ablation. Intratracheal instillation of DT in transgenic mice expressing human diphtheria toxin (DT) receptor targeted to ECs resulted in ablation of &gt;70% of lung ECs, producing severe ALI with near complete resolution by 7 days. Using single-cell RNA sequencing, eight distinct endothelial clusters were resolved, including alveolar aerocytes (aCap) ECs expressing apelin at baseline and general capillary (gCap) ECs expressing the apelin receptor. At 3 days post-injury, a novel gCap EC population emerged characterized by de novo expression of apelin, together with the stem cell marker, protein C receptor. These stem-like cells transitioned at 5 days to proliferative endothelial progenitor-like cells, expressing apelin receptor together with the pro-proliferative transcription factor, Foxm1, and were responsible for the rapid replenishment of all depleted EC populations by 7 days post-injury. Treatment with an apelin receptor antagonist prevented ALI resolution and resulted in excessive mortality, consistent with a central role for apelin signaling in EC regeneration and microvascular repair. The lung has a remarkable capacity for microvasculature EC regeneration which is orchestrated by newly emergent apelin-expressing gCap endothelial stem-like cells that give rise to highly proliferative, apelin receptor-positive endothelial progenitors responsible for the regeneration of the lung microvasculature

    Decision Making Regarding Aircraft De-Icing and In-Flight Icing Using the Canadian Airport Nowcasting System (CAN-Now)

    No full text
    The Canadian Airport Nowcasting Project (CAN-Now) has developed an advanced prototype all-season weather forecasting and nowcasting system that can be used at major airports. This system uses numerical model data, pilot reports, ground in-situ sensor observations (precipitation, icing, ceiling, visibility, winds, etc), on-site remote sensing (such as vertically pointing radar and microwave radiometer) and off-site remote sensing (satellite and radar) information to provide detailed nowcasts out to approximately 6 hours. The nowcasts, or short term weather forecasts, should allow decision makers at airports such as pilots, dispatchers, deicing crews, ground personnel or air traffic controllers to make plans with increased margins of safety and improved efficiency. The system is being developed and tested at Toronto Pearson International Airport (CYYZ) and Vancouver International Airport (CYVR). A Situation Chart has been developed to allow users to have a high glance value product which identifies significant weather related problems at the airport. Some new products combining observations and numerical model output into nowcasts are being tested. This talk will describe the uses of the system for decisions regarding aircraft de-icing at the ground and in-flight icing over the airport. Some statistical verifications of forecast products regarding precipitation amount, precipitation type, in-flight icing, etc, will be given
    corecore