Method to evaluate the efficiency of manual overhead irrigation in citrus rootstock liner production

Brazil produces grafted citrus seedlings in closed screen houses to reduce pest and disease incidence. Irrigation is usually performed by hand using either breaker nozzles or drilled polyvinyl chloride (PVC) pipe wands on garden hoses. Rootstocks are produced in cone-shaped containers filled with soilless potting mix. Since the containers have a small upper diameter, nutrient solution capture is reduced with the potential to cause environmental contamination from inefficient fertigation. This study provides a method to assess the efficiency of manual overhead irrigation systems used in liner production. The method consists of determining both the volume of water applied and volume lost (i.e., directly and by percolation) in order to obtain an estimate of the percentage of water loss, irrigation efficiency, and the drainage fraction. The method was tested in a commercial facility under standard production practices. The method's attributes included simplicity, quick sampling and data collection, and accuracy. The evaluated nursery was found to have low irrigation efficiency (27.14%) and excessive nutrient solution losses (72.86%). Considering an average production of 300,000 liners per year on 20,000 m(2), we determined an annual solution loss of 221.8 m(3) with an average environmental release of 158.9 kg of fertilizer. Therefore, more efficient irrigation systems are necessary for sustainable citrus rootstock liners production.364724735CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES479,394/2006-7; 479,665/2009-5Sem informaçã

Kalman-filter control schemes for fringe tracking. Development and application to VLTI/GRAVITY

The implementation of fringe tracking for optical interferometers is inevitable when optimal exploitation of the instrumental capacities is desired. Fringe tracking allows continuous fringe observation, considerably increasing the sensitivity of the interferometric system. In addition to the correction of atmospheric path-length differences, a decent control algorithm should correct for disturbances introduced by instrumental vibrations, and deal with other errors propagating in the optical trains. We attempt to construct control schemes based on Kalman filters. Kalman filtering is an optimal data processing algorithm for tracking and correcting a system on which observations are performed. As a direct application, control schemes are designed for GRAVITY, a future four-telescope near-infrared beam combiner for the Very Large Telescope Interferometer (VLTI). We base our study on recent work in adaptive-optics control. The technique is to describe perturbations of fringe phases in terms of an a priori model. The model allows us to optimize the tracking of fringes, in that it is adapted to the prevailing perturbations. Since the model is of a parametric nature, a parameter identification needs to be included. Different possibilities exist to generalize to the four-telescope fringe tracking that is useful for GRAVITY. On the basis of a two-telescope Kalman-filtering control algorithm, a set of two properly working control algorithms for four-telescope fringe tracking is constructed. The control schemes are designed to take into account flux problems and low-signal baselines. First simulations of the fringe-tracking process indicate that the defined schemes meet the requirements for GRAVITY and allow us to distinguish in performance. In a future paper, we will compare the performances of classical fringe tracking to our Kalman-filter control.Comment: 17 pages, 8 figures, accepted for publication in A&

Drug Delivery Micropump with Built-In Monitoring

AbstractWe report on the fabrication of the first MEMS micropump including an integrated pressure sensor. The signal of this sensor allows direct insight into the pump's operating dynamics and enables real-time self-monitoring. We demonstrate the changes in the sensor signal under different pumping conditions, including the presence of air in the pumping chamber and a downstream occlusions. Deviations from normal operating conditions create clear and characteristic deviations from the normal signal. These deviations will be exploited to detect extraordinary or faulty pumping conditions during use

Decadal-centennial scale monsoon variations in the Arabian Sea during the Early Holocene

An essential prerequisite for the prediction of future climate change due to anthropogenic input is an understanding of the natural processes that control Earth's climate on timescales comparable to human-lifespan. The Early Holocene period was chosen to study the natural climate variability in a warm interval when solar insolation was at its maximum. The monsoonal system of the Tropics is highly sensitive to seasonal variations in solar insolation, and consequently marine sediments from the region are a potential monitor of past climate change. Here we show that during the Early Holocene period rapid

Hearing without listening: attending to a quiet audiobook

Careful systematic tests of hearing ability may miss the cognitive consequences of sub-optimal hearing when listening in the real world. In Experiment One, sub-optimal hearing is simulated by presenting an audiobook at a quiet but discriminable level over 50 minutes. Recall of facts, words and inferences are assessed and performance compared to another group at a comfortable listening volume. At the quiet intensity, participants are able to detect, discriminate and identify spoken words but do so at a cost to sequential accuracy and fact recall when attention must be sustained over time. To exclude other interpretations, the effects are studied in Experiment Two by comparing recall to the same sentences presented in isolation. Here, the differences disappear. The results demonstrate that the cognitive consequences of listening at low volume arise when sustained attention is demanded over time

Spatiotemporal epidemiology of rabies at an interface between domestic dogs and wildlife in South Africa

We characterized the spatiotemporal epidemiology of rabies from January 2009 through March 2014 across the interface between a wildlife reserve and communal livestock farming area in South Africa. Brain tissue from 344 animals of 28 different species were tested for lyssavirus antigen. Of these, 146 (42.4%) samples tested positive, of which 141 (96.6%) came from dogs. Brain samples of dogs were more likely to test positive for lyssavirus antigen if they were found and destroyed in the reserve, compared to samples originating from dogs outside the reserve (65.3% vs. 45.5%; odds ratio (OR) = 2.26, 95% confidence interval (CI) = 1.27–4.03), despite rabies surveillance outside the reserve being targeted to dogs that have a higher index of suspicion due to clinical or epidemiological evidence of infection. In the reserve, dogs were more likely to test positive for rabies if they were shot further from villages (OR = 1.42, 95% CI 1.18–1.71) and closer to water points (OR = 0.41, 95% CI 0.21–0.81). Our results provide a basis for refinement of existing surveillance and control programs to mitigate the threat of spillover of rabies to wildlife populations.http://www.nature.com/srepam2019Veterinary Tropical Disease

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

Galactic Centre science with an ELT.

10m-class telescopes such as the VLT and the Keck Telescope have allowed tremendous progress on the understanding of environment of Sgr A*, the supermassive black hole at the Galactic Centre. However, these telescopes and associated instrumentation are reaching limitations which can only be overcome with larger apertures. We will summarise the most recent results in this area: star and gas dynamics, the origin of massive stars in the central parsec, the detection of stars on almost relativistic orbits. We will then anticipate the results that two E-ELT projects, MICADO and EAGLE, are expected to allow