70 research outputs found
Revisiting Existing Classification Approaches for Building Materials Based on Hyperspectral Data
Pollution emissions into the drainage basin have direct impact on surface water quality. These emissions result from human activities that turn into pollution loads when they reach the water bodies, as point or diffuse sources. Their pollution potential depends on the characteristics and quantity of the transported materials. The estimation of pollution loads can assist decision-making in basin management. Knowledge about the potential pollution sources allows for a prioritization of pollution control policies to achieve the desired water quality. Consequently, it helps avoiding problems such as eutrophication of water bodies. The focus of the research described in this study is related to phosphorus emissions into river basins. The study area is the upper Iguazu basin that lies in the northeast region of the State of Paranå, Brazil, covering about 2,965 km² and around 4 million inhabitants live concentrated on just 16% of its area. The MoRE (Modeling of Regionalized Emissions) model was used to estimate phosphorus emissions. MoRE is a model that uses empirical approaches to model processes in analytical units, capable of using spatially distributed parameters, covering both, emissions from point sources as well as non-point sources. In order to model the processes, the basin was divided into 152 analytical units with an average size of 20 km². Available data was organized in a GIS environment. Using e.g. layers of precipitation, the Digital Terrain Model from a 1:10000 scale map as well as soils and land cover, which were derived from remote sensing imagery. Further data is used, such as point pollution discharges and statistical socio-economic data. The model shows that one of the main pollution sources in the upper Iguazu basin is the domestic sewage that enters the river as point source (effluents of treatment stations) and/or as diffuse pollution, caused by failures of sanitary sewer systems or clandestine sewer discharges, accounting for about 56% of the emissions. Second significant shares of emissions come from direct runoff or groundwater, being responsible for 32% of the total emissions. Finally, agricultural erosion and industry pathways represent 12% of emissions. This study shows that MoRE is capable of producing valid emission calculation on a relatively reduced input data basis
SHIMM as an atmospheric profiler on the Nickel Telescope
Optimal atmospheric conditions are beneficial for detecting exoplanets via
high contrast imaging (HCI), as speckles from adaptive optics' (AO's) residuals
can make it difficult to identify exoplanets. While AO systems greatly improve
our image quality, having access to real-time estimates of atmospheric
conditions could also help astronomers use their telescope time more
efficiently in the search for exoplanets as well as aid in the data reduction
process. The Shack-Hartmann Imaging Motion Monitor (SHIMM) is an atmospheric
profiler that utilizes a Shack-Hartmann wavefront sensor to create spot images
of a single star in order to reconstruct important atmospheric parameters such
as the Fried parameter (), profile and coherence time. Due to its
simplicity, the SHIMM can be directly used on a telescope to get in situ
measurements while observing. We present our implementation of the Nickel-SHIMM
design for the one meter Nickel Telescope at Lick Observatory. We utilize an
HCIPy simulation of turbulence propagating across a telescope aperture to
verify the SHIMM data reduction pipeline as we begin on-sky testing. We also
used on-sky data from the AO system on the Shane Telescope to further validate
our analysis, finding that both our simulation and data reduction pipeline are
consistent with previously determined results for the Fried parameter at the
Lick Observatory. Finally, we present first light results from commissioning of
the Nickel-SHIMM.Comment: Conference Proceedings for 2023 SPIE Optics and Photonics, Techniques
and Instrumentation for Detection of Exoplanets X
Artificially designed pathogens â a diagnostic option for future military deployments
Diagnostic microbial isolates of bio-safety levels 3 and 4 are difficult to handle in medical field camps under military deployment settings. International transport of such isolates is challenging due to restrictions by the International Air Transport Association. An alternative option might be inactivation and sequencing of the pathogen at the deployment site with subsequent sequence-based revitalization in well-equipped laboratories in the home country for further scientific assessment. A literature review was written based on a PubMed search. First described for poliovirus in 2002, de novo synthesis of pathogens based on their sequence information has become a well-established procedure in science. Successful syntheses have been demonstrated for both viruses and prokaryotes. However, the technology is not yet available for routine diagnostic purposes. Due to the potential utility of diagnostic sequencing and sequence-based de novo synthesis of pathogens, it seems worthwhile to establish the technology for diagnostic purposes over the intermediate term. This is particularly true for resource-restricted deployment settings, where safe handling of harmful pathogens cannot always be guaranteed. peerReviewed
Document type: Articl
Crop Scouting Basics
With planting wrapping up and crops beginning to emerge, now is the time to start scouting fields regularly throughout the growing season for any potential issues. Scouting fields and monitoring crops throughout the growing season can help you make more informed management decisions and stay on top of potential issues that may come up during the growing season. Even if some issues cannot be fixed, regular scouting can help us better understand what happened in the field and make adjustments to reduce issues in the future. This article will discuss the basics of crop scouting as well as crop scouting tools and resources
Using the Gerchberg-Saxton algorithm to reconstruct non-modulated pyramid wavefront sensor measurements
Adaptive optics (AO) is a technique to improve the resolution of ground-based
telescopes by correcting, in real-time, optical aberrations due to atmospheric
turbulence and the telescope itself. With the rise of Giant Segmented Mirror
Telescopes (GSMT), AO is needed more than ever to reach the full potential of
these future observatories. One of the main performance drivers of an AO system
is the wavefront sensing operation, consisting of measuring the shape of the
above mentioned optical aberrations. Aims. The non-modulated pyramid wavefront
sensor (nPWFS) is a wavefront sensor with high sensitivity, allowing the limits
of AO systems to be pushed. The high sensitivity comes at the expense of its
dynamic range, which makes it a highly non-linear sensor. We propose here a
novel way to invert nPWFS signals by using the principle of reciprocity of
light propagation and the Gerchberg-Saxton (GS) algorithm. We test the
performance of this reconstructor in two steps: the technique is first
implemented in simulations, where some of its basic properties are studied.
Then, the GS reconstructor is tested on the Santa Cruz Extreme Adaptive optics
Laboratory (SEAL) testbed located at the University of California Santa Cruz.
This new way to invert the nPWFS measurements allows us to drastically increase
the dynamic range of the reconstruction for the nPWFS, pushing the dynamics
close to a modulated PWFS. The reconstructor is an iterative algorithm
requiring heavy computational burden, which could be an issue for real-time
purposes in its current implementation. However, this new reconstructor could
still be helpful in the case of many wavefront control operations. This
reconstruction technique has also been successfully tested on the Santa Cruz
Extreme AO Laboratory (SEAL) bench where it is now used as the standard way to
invert nPWFS signal
Spherical arena reveals optokinetic response tuning to stimulus location, size, and frequency across entire visual field of larval zebrafish
Many animals have large visual fields, and sensory circuits may sample those regions of visual space most relevant to behaviours such as gaze stabilisation and hunting. Despite this, relatively small displays are often used in vision neuroscience. To sample stimulus locations across most of the visual field, we built a spherical stimulus arena with 14,848 independently controllable LEDs. We measured the optokinetic response gain of immobilised zebrafish larvae to stimuli of different steradian size and visual field locations. We find that the two eyes are less yoked than previously thought and that spatial frequency tuning is similar across visual field positions. However, zebrafish react most strongly to lateral, nearly equatorial stimuli, consistent with previously reported spatial densities of red, green and blue photoreceptors. Upside-down experiments suggest further extra-retinal processing. Our results demonstrate that motion vision circuits in zebrafish are anisotropic, and preferentially monitor areas with putative behavioural relevance
Update on the Preliminary Design of SCALES: the Santa Cruz Array of Lenslets for Exoplanet Spectroscopy
SCALES (Santa Cruz Array of Lenslets for Exoplanet Spectroscopy) is a 2-5
micron high-contrast lenslet integral-field spectrograph (IFS) driven by
exoplanet characterization science requirements and will operate at W. M. Keck
Observatory. Its fully cryogenic optical train uses a custom silicon lenslet
array, selectable coronagraphs, and dispersive prisms to carry out integral
field spectroscopy over a 2.2 arcsec field of view at Keck with low ()
spectral resolution. A small, dedicated section of the lenslet array feeds an
image slicer module that allows for medium spectral resolution (),
which has not been available at the diffraction limit with a coronagraphic
instrument before. Unlike previous IFS exoplanet instruments, SCALES is capable
of characterizing cold exoplanet and brown dwarf atmospheres ( K) at
bandpasses where these bodies emit most of their radiation while capturing
relevant molecular spectral features.Comment: 24 pages, 13 figures, SPIE Astronomical Instruments and Telescopes
2020 conferenc
Mental health related determinants of parenting stress among urban mothers of young children â results from a birth-cohort study in Ghana and CĂ´te dâIvoire
Background There are limited data on the parenting stress (PS) levels in sub-Saharan African mothers and on the association between ante- and postnatal depression and anxiety on PS. Methods A longitudinal birth cohort of 577 women from Ghana and CĂ´te dâIvoire was followed from the 3rd trimester in pregnancy to 2 years postpartum between 2010 and 2013. Depression and anxiety were assessed by the Patient Health Questionnaire depression module (PHQ-9) and the Generalized Anxiety Disorder (GAD-7) at baseline, 3 month, 12 month and 24 month postpartum. PS was measured using the Parenting Stress Index-Short Form (PSI-SF) at 3, 12 and 24 month. The mean total PS score and the subscale scores were compared among depressed vs. non-depressed and among anxious vs. non-anxious mothers at 3, 12 and 24 month postpartum. The proportions of clinical PS (PSI-SF raw scoreâ>â90) in depressed vs. non-depressed and anxious vs. non-anxious mothers were also compared. A generalized estimating equation (GEE) approach was used to estimate population-averaged associations between womenâs depression/anxiety and PS adjusting for age, child sex, womenâs anemia, education, occupation, spouseâs education, and number of sick child visits. Results A total of 577, 531 and 264 women completed the PS assessment at 3 month, 12 month and 24 month postpartum across the two sites and the prevalences of clinical PS at each time point was 33.1%, 24.4% and 14.9% in Ghana and 30.2%, 33.5% and 22.6% in CĂ´te dâIvoire, respectively. At all three time points, the PS scores were significantly higher among depressed mothers vs. non-depressed mothers. In the multivariate regression analyses, antepartum and postpartum depression were consistently associated with PS after adjusting for other variables. Conclusions Parenting stress is frequent and levels are high compared with previous studies from high-income countries. Antepartum and postpartum depression were both associated with PS, while antepartum and postpartum anxiety were not after adjusting for confounders. More quantitative and qualitative data are needed in sub-Saharan African populations to assess the burden of PS and understand associated mechanisms. Should our findings be replicated, it appears prudent to design and subsequently evaluate intervention strategies
Flutriciclamide (18F-GE180) PET:first in human PET study of novel 3rd generation in vivo marker of human translator protein
Neuroinflammation is associated with neurodegenerative disease. PET radioligands targeting the 18-kDa translocator protein (TSPO) have been used as in vivo markers of neuroinflammation, but there is an urgent need for novel probes with improved signal-to-noise ratio. Flutriciclamide (18F-GE180) is a recently developed third-generation TSPO ligand. In this first study, we evaluated the optimum scan duration and kinetic modeling strategies for 18F-GE180 PET in (older) healthy controls
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