Zika virus (ZIKV) transmission through semen donation has never been reported but the risk is supported by the detection of ZIKV in semen and the demonstration of ZIKV sexual transmission. The ...potential impact of ZIKV on assisted reproductive procedures should be evaluated.
We tested longitudinally collected semen samples provided by asymptomatic blood donors who tested positive for ZIKV RNA in plasma during ZIKV outbreaks in Puerto Rico and Florida in 2016.
Five of the 14 (35.7%) asymptomatic blood donors provided semen samples that tested positive for ZIKV RNA, with ZIKV RNA loads ranging from 8.03 × 103 to 2.55 × 106 copies/mL. Plasma collected at the same time as the semen tested negative for ZIKV RNA for most ZIKV RNA-positive semen collections; all corresponding plasma samples tested positive or equivocal for anti-ZIKV IgG antibodies and all except one tested positive for ZIKV IgM antibodies. The rate of detection of ZIKV RNA in semen in asymptomatic donors is not significantly different from the rate previously reported for symptomatic patients.
Our results that show a high percentage of detection of ZIKV RNA in the semen of asymptomatic men confirm that ZIKV is a new threat for reproductive medicine and should have important implications for assisted reproductive technology. We recommend that semen donations from men at risk for ZIKV infection should be tested for ZIKV RNA, regardless of symptoms of ZIKV infection.
Nowadays, state-of-the-art direct visual odometry (VO) methods essentially rely on points to estimate the pose of the camera and reconstruct the environment. Direct Sparse Odometry (DSO) became the ...standard technique and many approaches have been developed from it. However, only recently, two monocular plane-based DSOs have been presented. The first one uses a learning-based plane estimator to generate coarse planes as input for optimization. When these coarse estimates are too far from the minimum, the optimization may fail. Thus, the entire system result is dependent on the quality of the plane predictions and restricted to the training data domain. The second one only detects planes in vertical and horizontal orientation as being more adequate to structured environments. To the best of our knowledge, we propose the first Stereo Plane-based VO inspired by the DSO framework. Differing from the above-mentioned methods, our approach purely uses planes as features in the sliding window optimization and uses a dual quaternion as pose parameterization. The conducted experiments showed that our method presents a similar performance to Stereo DSO, a point-based approach.
Pancreatic cancer is one of the most lethal malignancies, with virtually all patients eventually succumbing to their disease. Mutations in p53 have been documented in >50% of pancreatic cancers. ...Owing to the high incidence of p53 mutations in PanIN 3 lesions and pancreatic tumors, we interrogated the comparative ability of adult pancreatic acinar and ductal cells to respond to oncogenic Kras and mutant Tp53(R172H) using Hnf1b:CreER(T2) and Mist1:CreER(T2) mice. These studies involved co-activation of a membrane-tethered GFP lineage label, allowing for direct visualization and isolation of cells undergoing Kras and mutant p53 activation. Kras activation in Mist1(+) adult acinar cells resulted in brisk PanIN formation, whereas no evidence of pancreatic neoplasia was observed for up to 6 months following Kras activation in Hnf1beta(+) adult ductal cells. In contrast to the lack of response to oncogenic Kras alone, simultaneous activation of Kras and mutant p53 in adult ductal epithelium generated invasive PDAC in 75% of mice as early as 2.5 months after tamoxifen administration. These data demonstrate that pancreatic ductal cells, whereas exhibiting relative resistance to oncogenic Kras alone, can serve as an effective cell of origin for pancreatic ductal adenocarcinoma in the setting of gain-of-function mutations in p53.
This paper presents results from experiments in a large flume on wave and flow attenuation by a full-scale artificial Posidonia oceanica seagrass meadow in shallow water. Wave height and in-canopy ...wave-induced flows were reduced by the meadow under all tested regular and irregular wave conditions, and were affected by seagrass density, submergence and distance from the leading edge. The energy of irregular waves was reduced at all components of the spectra, but reduction was greater at the peak spectral frequency. Energy dissipation factors were largest for waves with small orbital amplitudes and at low wave Reynolds numbers. An empirical model, commonly applied to predict friction factors by rough beds, proved applicable to the P. oceanica bed. However at the lowest Reynolds numbers, under irregular waves, the data deviated significantly from the model. In addition, the wave-induced flow dissipation in the lower canopy increased with increasing wave orbital amplitude and increasing density of the mimics. The analysis of the wave-induced flow spectra confirm this trend: the reduction of flow was greatest at the longer period component of the spectra. Finally, we discuss the implications of these findings for sediment dynamics and the role of P. oceanica beds in protecting the shore from erosion.
► Full scale tests with Posidonia oceanica indicate that the seagrass reduces wave energy and wave-induced flows. ► Energy dissipation factors produced by the submerged canopy decay with wave orbital amplitude. ► Energy dissipation may be predicted by existing empirical formulae and canopy roughness may be estimated. ► In-canopy wave-induced flow reduction increases with increasing wave orbital amplitude and with increasing period of the flow spectra component. ► Effects of plant density, submergence ratios (hs/D) and distance from the leading edge were analysed.
The entrainment phenomenon, by which an oscillator adjusts its natural rhythm to an external periodic signal, has been observed in many natural systems. Recently, attention has focused on which are ...the optimal conditions for achieving entrainment. Here we use a semiconductor laser with optical feedback, operating in the low-frequency fluctuations (LFFs) regime, as a testbed for a controlled entrainment experiment. In the LFF regime the laser intensity displays abrupt spikes, which can be entrained to a weak periodic signal that directly modulates the laser pump current. We compare the performance of three modulation waveforms for producing 1:1 locking (one spike is emitted in each modulation cycle), as well as higher order locking regimes. We characterize the parameter regions where high-quality locking occurs, and those where the laser emits spikes which are not entrained to the external signal. The role of the modulation amplitude and frequency, and the role of the dc value of the laser pump current (that controls the natural spike frequency) in the entrainment quality are discussed.
Direct measurements of bed shear in the swash zone are presented. The data were obtained using a shear plate in medium and large-scale laboratory bore-driven swash and cover a wide range of bed ...roughness. Data were obtained across the full width of the swash zone and are contrasted with data from the inner surf zone. Estimates of the flow velocities through the full swash cycle were obtained through numerical modelling and calibrated against measured velocity data. The measured stresses and calculated flow velocities were subsequently used to back-calculate instantaneous local skin friction coefficients using the quadratic drag law. The data show rapid temporal variation of the bed shear stress through the leading edge of the uprush, which is typically two–four times greater than the backwash shear stresses at corresponding flow velocity. The measurements indicate strong temporal variation in the skin friction coefficient, particularly in the backwash. The general behaviour of the skin friction coefficient with Reynolds number is consistent with classical theory for certain stages of the swash cycle. A spatial variation in skin friction coefficient is also identified, which is greatest across the surf-swash boundary and likely related to variations in local turbulent intensities. Skin friction coefficients during the uprush are approximately twice those in the backwash at corresponding Reynolds number and cross-shore location. It is suggested that this is a result of the no-slip condition at the tip leading to a continually developing leading edge and boundary layer, into which high velocity fluid and momentum are constantly injected from the flow behind and above the tip region. Finally, the measured stress data are used to determine the asymmetry and cross-shore variation in potential sediment transport predicted by three forms of sediment transport formulae.
This study presents the analysis of the water surface elevation, velocity and suspended sediment concentration measurements obtained at a large wave flume under mobile bed conditions. The wave ...reproduced erosive and accretive conditions, and included monochromatic, short waves perturbed with a free long wave, bichromatic and random conditions. Each tested condition started from a handmade 1/15 slope and lasted for an approximate time period of 2.4h (6 runs of the selected wave condition), to compare the different beach profile developments and, in particular, the events that control sediment transport in the swash and surf zones. All erosive tested conditions produced a shoreline retreat and a bar at the breaking area whose development in time is directly correlated to the length of the breaking area. On the other hand, not all accretive conditions present a shoreward transport, and random conditions do not seem to alter the initial profile. The processed data show the suspended sediment event control produced by the existence or absence of wave–backwash interactions in the swash zone. The existence of these interactions, and their number within the wave group, will be a key parameter in controlling the sediment stirring, water velocity magnitudes and, therefore, the suspended sediment fluxes in the inner surf and outer swash.
•Hydrodynamic and morphodynamic measurements in the surf and swash zone.•Erosive and Accretive series reproducing monochromatic, bichromatic and random series.•Long wave control the number of wave–backwash interactions.•Wave group/short wave periods ratio is important for the sediment fluxes.•Short waves breaking at the shoreline are more efficient to create berms.
New large-scale laboratory data are presented on the influence of long waves, bichromatic wave groups and random waves on sediment transport in the surf and swash zones. Physical model testing was ...performed in the large-scale CIEM wave flume at UPC, Barcelona, as part of the SUSCO (swash zone response under grouping storm conditions) experiment in the Hydralab III program (Vicinanza et al., 2010). Fourteen different wave conditions were used, encompassing monochromatic waves, bichromatic wave groups and random waves. The experiments were designed specifically to compare variations in beach profile evolution between monochromatic waves and unsteady waves with the same mean energy flux. Each test commenced with approximately the same initial profile. The monochromatic conditions were perturbed with free long waves, and then subsequently substituted with bichromatic wave groups with different bandwidth and with random waves with varying groupiness. Beach profile measurements were made at half-hourly and hourly intervals, from which net cross-shore transport rates were calculated for the different wave conditions. Pairs of experiments with slightly different bandwidth or wave grouping show very similar net cross-shore sediment transport patterns, giving high confidence to the data set. Consistent with recent small-scale experiments, the data clearly show that in comparison to monochromatic conditions the bichromatic wave groups reduce onshore transport during accretive conditions and increase offshore transport during erosive conditions. The random waves have a similar influence to the bichromatic wave groups, promoting offshore transport, in comparison to the monochromatic conditions. The data also indicate that the free long waves promote onshore transport, but the conclusions are more tentative as a result of a few errors in the test schedule and modifications to the setup which reduced testing time. The experiments suggest that the inclusion of long wave and wave group sediment transport is important for improved near-shore morphological modeling of cross-shore beach profile evolution, and they provide a very comprehensive and controlled series of tests for evaluating numerical models. It is suggested that the large change in the beach response between monochromatic conditions and wave group conditions is a result of the increased significant and maximum wave heights in the wave groups, as much as the presence of the forced and free long waves induced by the groupiness. The equilibrium state model concept can provide a heuristic explanation of the influence of the wave groups on the bulk beach profile response if their effective relative fall velocity is larger than that of monochromatic waves with the same incident energy flux.
The planning of safe paths is an important issue for autonomous robot systems. The Probabilistic Foam method (PFM) is a planner that guarantees safe paths bounded by a sequence of structures called ...bubbles that provides safe regions. This method performs the planning by covering the free configuration space with bubbles, an approach analogous to a breadth-first search. To improve the propagation process and keep the safety, we present three algorithms based on Probabilistic Foam: Goal-biased Probabilistic Foam (GBPF), Radius-biased Probabilistic Foam (RBPF), and Heuristic-guided Probabilistic Foam (HPF); the last two are proposed in this work. The variant GBPF is fast, HPF finds short paths, and RBPF finds high-clearance paths. Some simulations were performed using four different maps to analyze the behavior and performance of the methods. Besides, the safety was analyzed considering the new propagation strategies.
PDF
