Analog-digital simulation of transient-induced logic errors and upset susceptibility of an advanced control system

A simulation study is described which predicts the susceptibility of an advanced control system to electrical transients resulting in logic errors, latched errors, error propagation, and digital upset. The system is based on a custom-designed microprocessor and it incorporates fault-tolerant techniques. The system under test and the method to perform the transient injection experiment are described. Results for 2100 transient injections are analyzed and classified according to charge level, type of error, and location of injection

Numerical Analysis and Wind Tunnel Validation of Droplet Distribution in the Wake of an Unmanned Aerial Spraying System in Forward Flight

Recent developments in agriculture mechanization have generated significant challenges towards sustainable approaches to reduce the environmental footprint and improve food quality. This paper highlights the benefits of using unmanned aerial systems (UASs) for precision spraying applications of pesticides, reducing the environmental risk and waste caused by spray drift. Several unmanned aerial spraying system (UASS) operation parameters and spray system designs are examined to define adequate configurations for specific treatments. A hexarotor DJI Matrice 600 equipped with T-Motor “15 × 5” carbon fiber blades is tested numerically using computational fluid dynamics (CFD) and experimentally in a wind tunnel. These tests assess the aerodynamic interaction between the wake of an advancing multicopter and the fine droplets generated by atomizers traditionally used in agricultural applications. The aim of this research is twofold. First, we analyze the effects of parameters such as flight speed (0, 2, and 3 m·s (Formula presented.)), nozzle type (hollowcone and fan), and injection pressure (2–3 bar) on spray distribution. In the second phase, we use data from the experimental campaign to validate numerical tools for the simulation of rotor–droplet interactions necessary to predict spray’s ground footprint and to plan a precise guidance algorithm to achieve on-target deposition and reduce the well-known droplet drift problem

Stem cells and their role in pituitary tumorigenesis

The presence of adult pituitary stem cells (PSCs) has been described in murine systems by comprehensive cellular profiling and genetic lineage tracing experiments. PSCs are thought to maintain multipotent capacity throughout life and give rise to all hormone-producing cell lineages, playing a role in pituitary gland homeostasis. Additionally, PSCs have been proposed to play a role in pituitary tumorigenesis, in both adenomas and adamantinomatous craniopharyngiomas. In this manuscript, we discuss the different approaches used to demonstrate the presence of PSCs in the murine adult pituitary, from marker analyses to genetic tracing. In addition, we review the published literature suggesting the existence of tumor stem cells in mouse and human pituitary tumors. Finally, we discuss the potential role of PSCs in pituitary tumorigenesis in the context of current models of carcinogenesis and present evidence showing that in contrast to pituitary adenoma, which follows a classical cancer stem cell paradigm, a novel mechanism has been revealed for paracrine, non-cell autonomous tumor initiation in adamantinomatous craniopharyngioma, a benign but clinically aggressive pediatric tumor

Experimental and numerical analysis of hovering multicopter performance in low-Reynolds number conditions

Unmanned Aircraft Systems (UAS) are state of the art in the aerospace industry and are involved in many operations. Although initially developed for military purposes, commercial applications of small- scale UAS, such as multicopters, are abundant today. Accurate engineering tools are required to assess the performance of these vehicles and optimize power consumption. The thrust and power curves of the rotors used by small-scale UAS are essential elements in designing efficient aircraft. The scarcity of experimental data and sufficiently accurate prediction models to evaluate rotor aerodynamic performance in the flight envelope are primary limitations in UAS science. In addition, for small-scale rotors at usual rotation rates, chord-based Reynolds numbers are typically smaller than 100,000, a flow regime in which performance tends to degrade. In this paper, experimental data on small-scale multicopter propulsion systems are presented and combined with a Computational Fluid Dynamics (CFD) model to describe the aerodynamics of these vehicles in low Reynolds numbers conditions. We use the STAR-CCM+ software to perform CFD simulations adopting both a dynamic-grid, time-accurate analysis and a static-grid, steady- state technique that solves the Navier-Stokes equations in a suitable framework. Comparing numerical simulation results on a conventional UAS propeller with related experimental data suggests that the proposed approach can correctly describe the thrust and torque coefficients in the range of Reynolds numbers characterizing the UAS flight envelope

Actin dynamics coupled to clathrin-coated vesicle formation at the trans-Golgi network

In diverse species, actin assembly facilitates clathrin-coated vesicle (CCV) formation during endocytosis. This role might be an adaptation specific to the unique environment at the cell cortex, or it might be fundamental, facilitating CCV formation on different membranes. Proteins of the Sla2p/Hip1R family bind to actin and clathrin at endocytic sites in yeast and mammals. We hypothesized that Hip1R might also coordinate actin assembly with clathrin budding at the trans-Golgi network (TGN). Using deconvolution and time-lapse microscopy, we showed that Hip1R is present on CCVs emerging from the TGN. These vesicles contain the mannose 6-phosphate receptor involved in targeting proteins to the lysosome, and the actin nucleating Arp2/3 complex. Silencing of Hip1R expression by RNAi resulted in disruption of Golgi organization and accumulation of F-actin structures associated with CCVs on the TGN. Hip1R silencing and actin poisons slowed cathepsin D exit from the TGN. These studies establish roles for Hip1R and actin in CCV budding from the TGN for lysosome biogenesis

Cellulose Nanocrystal Membranes as Excipients for Drug Delivery Systems

In this work, cellulose nanocrystals (CNCs) were obtained from flax fibers by an acid hydrolysis assisted by sonochemistry in order to reduce reaction times. The cavitation inducted during hydrolysis resulted in CNC with uniform shapes, and thus further pretreatments into the cellulose are not required. The obtained CNC exhibited a homogeneous morphology and high crystallinity, as well as typical values for surface charge. Additionally, CNC membranes were developed from CNC solution to evaluation as a drug delivery system by the incorporation of a model drug. The drug delivery studies were carried out using chlorhexidine (CHX) as a drug and the antimicrobial efficiency of the CNC membrane loaded with CHX was examined against Gram-positive bacteria Staphylococcus aureus (S. Aureus). The release of CHX from the CNC membranes is determined by UV-Vis. The obtaining methodology of the membranes proved to be simple, and these early studies showed a potential use in antibiotic drug delivery systems due to the release kinetics and the satisfactory antimicrobial activity.The authors would like to acknowledge the Department of Education, Universities and Investigation of the Basque Government (project IT1008-16), the Federal Agency for Support and Evaluation of Graduate Education (CAPES) through process BEX 8710/14-7, the Mexican Council of Science and Technology (CONACyT) through scholarship 216178 and theBrazilian National Council for Scientific and Technological Development for financial support through CNPq (# 482251/2013-1) for financially supporting this work. The authors also thank Maite Insausti and Oihane Arriortua for their kind help and support with Nanosizer and SGIker of the University of the Basque Country UPV/EHU for technical and human support provided with XRD, NMR and AFM characterizations and Altair Faes of the Regional Center of Oncology of the Federal University of Pelotas (UFPel) for the use of the equipment Eldorado 78

Changes in the simulation of atmospheric instability over the Iberian Peninsula due to the use of 3DVAR data assimilation

The ability of two downscaling experiments to correctly simulate thermodynamic conditions over the Iberian Peninsula (IP) is compared in this paper. To do so, three parameters used to evaluate the unstable conditions in the atmosphere are evaluated: the total totals index (TT), convective available potential energy (CAPE), and convective inhibition (CIN). The Weather and Research Forecasting (WRF) model is used for the simulations. The N experiment is driven by ERA-Interim's initial and boundary conditions. The D experiment has the same configuration as N, but the 3DVAR data assimilation step is additionally run at 00:00, 06:00, 12:00, and 18:00 UTC. Eight radiosondes are available over the IP, and the vertical temperature and moisture profiles from the radiosondes provided by the University of Wyoming and the Integrated Global Radiosonde Archive (IGRA) were used to calculate three parameters commonly used to represent atmospheric instability by our own methodology using the R package aiRthermo. According to the validation, the correlation, standard deviation (SD), and root mean squared error (RMSE) obtained by the D experiment for all the variables at most of the stations are better than those for N. The different methods produce small discrepancies between the values for TT, but these are larger for CAPE and CIN due to the dependency of these quantities on the initial conditions assumed for the calculation of a lifted air parcel. Similar results arise from the seasonal analysis concerning both WRF experiments: N tends to overestimate or underestimate (depending on the parameter) the variability of the reference values of the parameters, but D is able to capture it in most of the seasons. In general, D is able to produce more reliable results due to the more realistic values of dew point temperature and virtual temperature profiles over the IP. The heterogeneity of the studied variables is highlighted in the mean maps over the IP. According to those for D, the unstable air masses are found along the entire Atlantic coast during winter, but in summer they are located particularly over the Mediterranean coast. The convective inhibition is more extended towards inland at 00:00 UTC in those areas. However, high values are also observed near the southeastern corner of the IP (near Murcia) at 12:00 UTC. Finally, no linear relationship between TT, CAPE, or CIN was found, and consequently, CAPE and CIN should be preferred for the study of the instability of the atmosphere as more atmospheric layers are employed during their calculation than for the TT index.</p

Dynamical mass measurements of two protoplanetary discs

ALMA observations of line emission from planet forming discs have demonstrated to be an excellent tool to probe the internal disc kinematics, often revealing subtle effects related to important dynamical processes occurring in them, such as turbulence, or the presence of planets, that can be inferred from pressure bumps perturbing the gas motion, or from detection of the planetary wake. In particular, we have recently shown for the case of the massive disc in Elias 2-27 how one can use such kind of observations to measure deviations from Keplerianity induced by the disc self-gravity, thus constraining the total disc mass with good accuracy and independently on mass conversion factors between the tracer used and the total mass. Here, we refine our methodology and extend it to two additional sources, GM Aur and IM Lup, for which archival line observations are available for both the 12CO and the 13CO line. For IM Lup, we are able to obtain a consistent disc mass of Mdisc=0.1 Msun, implying a disc-star mass ratio of 0.1 (consistent with the observed spiral structure in the continuum emission) and a gas/dust ratio of ~ 65 (consistent with standard assumptions), with a systematic uncertainty by a factor ~2 due to the different methods to extract the rotation curve. For GM Aur, the two lines we use provide slightly inconsistent rotation curves, that cannot be attributed only to a difference in the height of the emitting layer, nor to a vertical temperature stratification. Our best fit disc mass measurement is Mdisc=0.26Msun, implying a disc-star mass ratio of ~0.35 and a gas/dust ratio of ~130... ABRIDGEDComment: 14 pages, 10 figures, MNRAS in pres