311 research outputs found
Characterization of a succession of small insect viruses in a wild South African population of Nudaurelia cytherea capensis (Lepidoptera: Saturniidae)
The Tetraviridae are a family of small insect RNA viruses first discovered in South Africa some 40 years ago. They consist of one or two single-stranded (+) RNAs encapsidated in an icosahedral capsid of approximately 40 nm in diameter, with T = 4 symmetry. The type members of the two genera within this family, Nudaurelia β virus (NβV) and Nudaurelia ω virus (NωV), infect Nudaurelia cytherea capensis (pine emperor moth) larvae. The absence of N. capensis laboratory colonies and tissue culture cell lines susceptible to virus infection have limited research on the biology of NβV and NωV because the availability of infectious virus is dependent upon sporadic outbreaks in the wild N. capensis populations. In September 2002, dead and dying N. capensis larvae exhibiting symptoms similar to those reported previously in other tetravirus infections were observed in a wild population in a pine forest in the Western Cape province of South Africa. We report here the isolation of three small insect viruses from this population over a period of three years. Transmission electron microscopy and serological characterization indicate that all three are tetra-like virus isolates. One isolate was shown by cDNA sequence analysis to be NβV, which was thought to have been extinct since 1985. The two other isolates are likely new tetraviruses, designated Nudaurelia ψ virus (NψV) and Nudaurelia ζ virus (NζV), which are morphologically and serologically related to NωV and NβV, respectively
Sensitivity analysis of existing exponential empirical formulas for pore pressure distribution inside breakwater core using numerical modeling
A series of numerical experiments were carried out to perform a sensitivity analysis for existing exponential empirical formulas for pore pressure distribution inside the breakwater core. The Forchheimer equation was solved using a CFD modeling (Flow-3D) along with the official license from the Flow Science, Inc. Pore pressure field observations of Zeebrugge breakwater core were used to calibrate the numerical model. Results of sensitivity analysis represented the wave period as an effective parameter on wave-induced pore pressure inside the rubble mound breakwater core and a sensitive parameter for empirical formulas hile other wave parameters like wave height and water depth did not stimulate the formulas sensitivity
A new VME trigger processor for the NA57 experiment
The ALICE experiment will use a trigger concept requiring independent deadtimes for each sub-detector system, and with detector-specific past-future protection. These features are implemented in a new VME-based trigger processor for the NA57 experiment. Monitoring and diagnostic features of the new trigger processor are also described.List of Figures Figure 1:ALICE trigger logic diagram. Figure 2:Layout of the NA57 experiment. Figure 3:Schematic layout of NA57 VME central trigger processor. Figure 4:Example of a trigger definition script. </A
The progestin-only contraceptive medroxyprogesterone acetate, but not norethisterone acetate, enhances HIV-1 Vpr-mediated apoptosis in human CD4+ T cells through the glucocorticoid receptor
The glucocorticoid receptor (GR) regulates several physiological functions, including immune function and apoptosis. The HIV-1 virus accessory protein, viral protein R (Vpr), can modulate the transcriptional response of the GR. Glucocorticoids (GCs) and Vpr have been reported to induce apoptosis in various cells, including T-cells. We have previously shown that the injectable contraceptive, medroxyprogesterone acetate (MPA) is a partial to full agonist for the GR, unlike norethisterone acetate (NET-A). We investigated the functional cross talk between the GR and Vpr in inducing apoptosis in CD4 + T-cells, in the absence and presence of GCs and these progestins, as well as progesterone. By using flow cytometry, we show that, in contrast to NET-A and progesterone, the synthetic GR ligand dexamethasone (Dex), cortisol and MPA induce apoptosis in primary CD4 + T-cells. Furthermore, the C-terminal part of the Vpr peptide, or HIV-1 pseudovirus, together with Dex or MPA further increased the apoptotic phenotype, unlike NET-A and progesterone. By a combination of Western blotting, PCR and the use of receptor- selective agonists, we provide evidence that the GR and the estrogen receptor are the only steroid receptors expressed in peripheral blood mononuclear cells. These results, together with the findings that RU486, a GR antagonist, prevents Dex-, MPA- and Vpr-mediated apoptosis, provide evidence for the first time that GR agonists or partial agonists increase apoptosis in primary CD4 + T-cells via the GR. We show that apoptotic induction involves differential expression of key apoptotic genes by both Vpr and GCs/MPA. This work suggests that contraceptive doses of MPA but not NET-A or physiological doses of progesterone could potentially accelerate depletion of CD4 + T-cells in a GR-dependent fashion in HIV-1 positive women, thereby contributing to immunodeficiency. The results imply that choice of progestin used in contraception may be critical to susceptibility and progression of diseases such as HIV-1
Lunar Surface exploration based on LCNS orbiters and Onboard Sensor observables
Lunar exploration is a strategic priority to develop and experiment technologies that will pave the way for the future missions to Mars and to other celestial bodies of the Solar System. Robots are expected to prepare the return of humans to the Moon by surveying landing sites, demonstrating in situ resource utilization (ISRU), and expanding our access capabilities to difficult areas, i.e., craters and caves. Succeeding in these challenging tasks requires reliable and efficient navigation and communication capabilities. Therefore, space agencies are encouraging the development of a Lunar Communication and Navigation Service (LCNS) to efficiently support lunar assets. A dedicated LCNS infrastructure would lead to unprecedent advantages in future missions by enabling a constant contact with Earth, even in case of Direct To Earth (DTE) link unavailability, e.g., on the far side of the Moon. To fulfil critical tasks, such as obstacle avoidance, instrument manoeuvring and reaching a precise location on the map, rover near real time positioning is a key requirement. Thus, in our work we investigate a method based on the Extended Kalman Filter (EKF) that implements a multi modal sensor fusion approach to estimate the rover's position and velocity by using observables collected by onboard sensors or provided by a LCNS constellation. We focus on a realistic mission scenario in the Moon's south polar region that includes a robotic vehicle hosting onboard sensors to estimate the travelled distances (Wheel Odometry, WO) and the heading variation (Inertial Measurement Unit, IMU). Furthermore, the LCNS orbiters are supposed to broadcast one-way radio signals that the rover user terminal can detect and exploit, providing GNSS-like functionalities. The rover's localization is accomplished through dead-reckoning during LCNS visibility gaps, by using IMU and WO data and accurate Digital Elevation Models (DEMs) of the lunar surface. Whenever pseudorange and pseudorange rate data are acquired by the rover LCNS terminal, these measurements are processed by the navigation filter in combination with IMU and WO datasets, while optimizing the position, velocity and timing (PVT) computation in terms of integrity, accuracy, and convergence time. The proposed method copes with highly varying LCNS visibility conditions and would significantly improve rover's navigation on the Moon's surface in regions where DTE is not achievable. Moreover, our results confirm that the LCNS would be a valuable source of information to be exploited in combination with onboard sensors to improve the accuracy of the reconstructed rover's traverse
Strangeness enhancement at mid-rapidity in Pb-Pb collisions at 158 GeV/c
, , , and negative particle yields and transverse mass spectra have been measured at central rapidity in Pb-Pb and p-Pb collisions at 158 GeV/. The yields in Pb-Pb interactions % are presented as a function of the collision centrality and compared with those obtained from p-Pb collisions. Strangeness enhancement in Pb-Pb relative to p-Pb collisions increases with the strangeness content of the particle. Going from p-Pb to Pb-Pb, the strange particle yields increase faster than linearly with the number of participants up to , thereafter the increase becomes %linear with . Yields are studied as a function of the number of nucleons participating in the collision , which is estimated with the Glauber model. From p-Pb to Pb-Pb collisions the particle yields per participant increase substantially. The enhancement is more pronounced for multistrange particles, and exceeds an order of magnitude for the . For a number of participants, , greater than , however, all yields per participant appear to be constant
Moon Landing Based on Multi-Sensor Fusion of Lunar Navigation Satellites and Onboard Sensor Observables
Determination of the number of wounded nucleons in Pb+Pb collisions at 158 A GeV/c
The charged particle multiplicity distributions measured by two experiments, WA97 and NA57, in Pb+Pb collisions at 158 A GeV/c have been analyzed in the framework of the wounded nucleon model (WNM). We obtain a good description of the data within the centrality range of our samples. This allows us to make use of the measured multiplicities to estimate the number of wounded nucleons of the collision
Frequency, kinetics and determinants of viable SARS-CoV-2 in bioaerosols from ambulatory COVID-19 patients infected with the Beta, Delta or Omicron variants.
Airborne transmission of SARS-CoV-2 aerosol remains contentious. Importantly, whether cough or breath-generated bioaerosols can harbor viable and replicating virus remains largely unclarified. We performed size-fractionated aerosol sampling (Andersen cascade impactor) and evaluated viral culturability in human cell lines (infectiousness), viral genetics, and host immunity in ambulatory participants with COVID-19. Sixty-one percent (27/44) and 50% (22/44) of participants emitted variant-specific culture-positive aerosols <10μm and <5μm, respectively, for up to 9 days after symptom onset. Aerosol culturability is significantly associated with lower neutralizing antibody titers, and suppression of transcriptomic pathways related to innate immunity and the humoral response. A nasopharyngeal Ct <17 rules-in ~40% of aerosol culture-positives and identifies those who are probably highly infectious. A parsimonious three transcript blood-based biosignature is highly predictive of infectious aerosol generation (PPV > 95%). There is considerable heterogeneity in potential infectiousness i.e., only 29% of participants were probably highly infectious (produced culture-positive aerosols <5μm at ~6 days after symptom onset). These data, which comprehensively confirm variant-specific culturable SARS-CoV-2 in aerosol, inform the targeting of transmission-related interventions and public health containment strategies emphasizing improved ventilation
DRD2/CHRNA5 Interaction on Prefrontal Biology and Physiology during Working Memory
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