ALBERT

Description: [1]  A one-year dataset spanning March 2011-March 2012 of coincident observations of night time thermospheric zonal neutral winds, equatorial plasma bubble (EPB) velocities, and zonal plasma drifts are used to examine the relationship between the thermosphere and ionosphere near the geomagnetic equator over Peru. Thermospheric neutral winds are determined by using a bi-static Fabry–Perot interferometer (FPI) experiment located at Merihill and Nazca in Peru. The ambient plasma drift velocities were obtained using the incoherent scatter radar at the Jicamarca Radio Observatory in Peru. The EPB zonal velocities were estimated utilizing images of the OI 630.0-nm emission recorded by a narrow-field optical imaging system at the Cerro Tololo Inter-American Observatory in Chile. The joint analysis of these datasets illustrates that the night time and night-to-night variations in the zonal neutral winds, EPB velocities, and plasma drifts are well correlated. This consistent result of the local time variations of the neutral winds with that of EPB and plasma drifts illustrates that the F -region dynamo is, in general, fully activated. However, at times, the magnitude of the EPB velocities and the plasma drifts are different from the neutral winds. It is plausible that such a difference is due either to the effect of polarization electric fields developed inside the EPB or due to the latitudinal gradient of the neutral winds and EPB velocity measurements since the EPB velocities are estimated at a higher latitude, corresponding to an apex altitude of ~400 km, than the wind estimates, which derive from an apex altitude of ~250 km.

Description: Inferring a temporal gene network from a crucial signaling pathway in leukemic cells is a leading problem in oncology. We built a temporal transcriptional network of B-cell receptor (BCR) crosslinking in CLL and healthy B-cells, a critical step to understand the dynamics of BCR gene expression and to understand gene regulation at a system level. CLL cells have defects in apoptosis and the BCR pathway appears crucial in this process, leading to differential signaling and cell response according to the Ig gene mutational status and zap70 expression. We built this network by analysis of the gene expression profile after BCR crosslinking in six mutated (M) and six unmutated (UM) CLL cells and six healthy B-cells. After a pilot study examining multiple time points, total RNA was purified at four time points (60 to 390 min) from stimulated (S) and unstimulated (US) cells, for a total of 170 HU133plus2.0 DNA-chips analyzed. The logarithmic ratio data log(S/US) for each time point and each patient and the linear combination for four time points were analyzed to score expression over time. This temporal clustering discriminates healthy B-cells from CLL-cells, but now also distinguishes two groups of patients, one mainly UM with higher zap70 protein levels. BCR engagement induces different gene expression for this group of aggressive CLL. We built a temporal model of gene expression for these three groups using two iterative steps. The first step is a modified K-means clustering approach using log(S/US) of temporal gene expression. This results in groups of genes with common temporal structure whose expression exhibits significant differences after BCR stimulation. The number of considered genes were then reduced, keeping a small number with the largest increase in expression within each group. Most of these genes are important in BCR transcription including JUN, DUSP1 and NFkB and most first wave genes are transcription factors. The second step is to construct predictive models of gene expression, considering only causal linear predictive models. Specifically the expression of an output gene at each time is predicted using a weighted linear combination of the expression of another gene at past time points. The method groups pairs of genes by common predictive model. While paired genes may reside in different initial clusters, upon convergence they are clustered by which predictive models they use. The procedure first assigns random pairings of genes and then we iterate between two steps, computing the best predictive model using a regularized least squares algorithm emphasizing sparse models and optimal gene pairings using a modified Hungarian bipartite graph matching approach. In practice the method converges in a small number of iterations. To refine and test this model we use RNAi to silence genes in the first wave of transcription after BCR stimulation and study the impact on the model. From the global gene regulatory network, we aim to predict the minimal number of gene to silence to influence the global structure of the BCR regulatory network. Influencing the transcriptional structure of aggressive CLL toward that of indolent CLL and healthy B-cells is a first step to reprogram the transcriptional response of leukemic cells.

Description: The development of detailed simulation models of water reclamation processors based on the ASPEN PLUS simulation program is discussed. Individual models have been developed for vapor compression distillation, vapor phase catalytic ammonia removal, and supercritical water oxidation. These models are used for predicting the process behavior. Particular attention is given to methodology which is used to complete this work, and the insights which are gained by this type of model development.

Description: It is the goal of developers of advanced life support researcher to develop technology that reduces the cost of life support for future space missions and thereby enables missions that are currently infeasible or too expensive. Because the cost of propulsion dominates the cost of hardware emplacement in space and because the mass of a deliverable object controls its propulsive requirements, equivalent system mass (ESM) is used as a means for accounting for mission costs. ESM is typically calculated by adding to the actual mass the equivalent amount of mass that must be added to a mission due to other characteristics of a piece of hardware such as the item s volume or energy requirements. This approach works well for comparing different pieces of hardware when they go to the same location in space. However, different locations in mission space such low Earth orbit, Mars surface, or full trip to Mars and return to low Earth orbit require vastly different amounts of propulsion. Moving an object from Earth surface to the Martian surface and returning it to Earth will require as much as 100 times the propulsion that is required to move the object to low Earth orbit only. This paper presents the case for including the effect that location can have on cost as a part of ESM and suggests a method for achieving this improvement of ESM.

Description: The Heat Melt Compactor (HMC) is designed to sterilize and process wastes produced during space missions. Benefits of the HMC include reduction of biohazards to the crew, reduction in volume of wastes that would otherwise require storage, production of radiation shielding tiles, and recovery of water and other resources. Water reuse is critical onboard spacecrafts; it reduces the need for resupply missions and saves valuable storage space. The main sources of water in HMC batches are food, beverages, shampoo, disinfecting wipes, toothpaste, and diapers. Water reclaimed by the HMC was analyzed for concentrations of Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO2-, Br-, NO3-, PO43-, SO42-, total organic carbon (TOC), total inorganic carbon (TIC), % total solids, and pH. The data are discussed in relation to the current water input characteristics established for the International Space Station Water Processor Assembly system. Batches with higher than average amounts of food produced HMC product water with higher sulfate content, and batches with higher proportions of disinfectant wipes and food yielded HMC product water with higher ammonium concentration. We also compared theoretical chemical composition of HMC product water based on food labels and literature values to experimental results.