1,385 research outputs found
The Fiber Optic Reel System: A Compact Deployment Solution for Tethered Live-Telemetry Deep-Sea Robots and Sensors
Tethered deep-sea robots and instrument platforms, such as Remotely Operated Vehicles (ROVs) and vertical-profiling or towed instrument arrays, commonly rely on fiber optics for real-time data transmission. Fiber optic tethers used for these applications are either heavily reinforced load-bearing cables used to support lifting and pulling, or bare optical fibers used in non-load bearing applications. Load-bearing tethers directly scale operations for deep-sea robots as the cable diameter, mass, and length typically require heavy winches and large surface support vessels to operate, and also guide the design of the deep-sea robot itself. In an effort to dramatically reduce the physical scale and operational overhead of tethered live-telemetry deep-sea robots and sensors, we have developed the Fiber Optic Reel System (FOReelS). FOReelS utilizes a customized electric fishing reel outfitted with a proprietary hollow-core braided fiber optic fishing line and mechanical termination assembly (FOFL), which offers an extremely small diameter (750 μm) load-bearing (90 lb/400 N breaking strength) tether to support live high-bandwidth data transmission as well as fiber optic sensing applications. The system incorporates a novel epoxy potted data payload system (DPS) that includes high-definition video, integrated lighting, rechargeable battery power, and gigabit ethernet fiber optic telemetry. In this paper we present the complete FOReelS design and field demonstrations to depths exceeding 780 m using small coastal support vessels of opportunity. FOReelS is likely the smallest form factor live-telemetry deep-sea exploration tool currently in existence, with a broad range of future applications envisioned for oceanographic sensing and communication
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Colloidal gas aphrons separation to obtain polyphenol rich fractions from artichoke agro-industrial discards
Artichoke agro-industrial discards have proved an excellent source of polyphenolic compounds with high antioxidant capacity. The aim of this study was to further separate these bioactive molecules from an ethanolic extract by using Colloidal Gas Aphrons (CGAs) generated from a cationic surfactant, Cetyl trimethylammonium bromide, CTAB (1 mM) and a nonionic one, Tween 20 (10 mM). Total proteins, total sugars, total phenolic content (TPC), antioxidant capacity (AOC) and polyphenolic profile were determined in the crude extracts and CGA fractions. Highest recovery was obtained with the nonionic Tween 20 at CGA to feed volumetric ratio 5 (RE% = 64) whereas the cationic CTAB proved more efficient (RE% = 58) at the highest ratio studied here (ratio 11). Antioxidant capacity followed the same trend as the recovery of polyphenols and highest enrichment in antioxidant activity for each of the surfactants (1.5 for Tween 20 and 1.4 for CTAB) was obtained at those conditions that led to maximum recovery. Highest selectivity was obtained with CTAB. Electrostatic interactions drove the separation with the cationic surfactant whereas with Tween 20 hydrophobic interactions were predominant. Polyphenolic profile of feed and CGAs fractions comprised mainly mono and dicaffeoylquinic acids and a small proportion of flavones. In most of the cases no enrichment of any particular polyphenol was found in CGAs samples. However, with Tween and at ratios 5 and 11 CGAs were enriched in dicaffeoylquinic acid. Future research should focus on assessing if the surfactant could also offer any advantage to the formulation of these polyphenols
Can Authorship Representation Learning Capture Stylistic Features?
Automatically disentangling an author's style from the content of their
writing is a longstanding and possibly insurmountable problem in computational
linguistics. At the same time, the availability of large text corpora furnished
with author labels has recently enabled learning authorship representations in
a purely data-driven manner for authorship attribution, a task that ostensibly
depends to a greater extent on encoding writing style than encoding content.
However, success on this surrogate task does not ensure that such
representations capture writing style since authorship could also be correlated
with other latent variables, such as topic. In an effort to better understand
the nature of the information these representations convey, and specifically to
validate the hypothesis that they chiefly encode writing style, we
systematically probe these representations through a series of targeted
experiments. The results of these experiments suggest that representations
learned for the surrogate authorship prediction task are indeed sensitive to
writing style. As a consequence, authorship representations may be expected to
be robust to certain kinds of data shift, such as topic drift over time.
Additionally, our findings may open the door to downstream applications that
require stylistic representations, such as style transfer.Comment: appearing at TACL 202
Quantifying Four Decades of Arid-region Agricultural Development in Arequipa, Peru Using Landsat
The Arequipa Nexus Institute for Food, Energy and the Environment (Nexus Institute) is located in Southwestern Peru, generally bounded by the city of Arequipa to the east, the Majes River to the west, the Pacific Ocean to the south, and the Andes mountains to the north. Though agriculture has been practiced in parts of this cool desert region (MAT~15°C, MA
Thyroid markers and body composition predict LDL-cholesterol change in lean healthy women on a ketogenic diet: experimental support for the lipid energy model
Introduction: There is a large heterogeneity in LDL-cholesterol change among individuals adopting ketogenic diets. Interestingly, lean metabolically healthy individuals seem to be particularly susceptible, with an inverse association between body mass index and LDL-cholesterol change. The lipid energy model proposes that, in lean healthy individuals, carbohydrate restriction upregulates systemic lipid trafficking to meet energy demands. To test if anthropometric and energy metabolism markers predict LDL-cholesterol change during carbohydrate restriction. Methods: Ten lean, healthy, premenopausal women who habitually consumed a ketogenic diet for ≥6 months were engaged in a three-phase crossover study consisting of continued nutritional ketosis, suppression of ketosis with carbohydrate reintroduction, and return to nutritional ketosis. Each phase lasted 21 days. The predictive performance of all available relevant variables was evaluated with the linear mixed-effects models. Results: All body composition metrics, free T3 and total T4, were significantly associated with LDL-cholesterol change. In an interaction model with BMI and free T3, both markers were significant independent and interacting predictors of LDL-cholesterol change. Neither saturated fat, HOMA-IR, leptin, adiponectin, TSH, nor rT3 was associated with LDL-cholesterol changes. Discussion: Among lean, healthy women undergoing carbohydrate restriction, body composition and energy metabolism markers are major drivers of LDL-cholesterol change, not saturated fat, consistent with the lipid energy model
Selective pattern of motor system damage in gamma-synuclein transgenic mice mirrors the respective pathology in amyotrophic lateral sclerosis
AbstractAmyotrophic lateral sclerosis (ALS) is characterised by substantial loss of both upper and lower motor neuron function, with sensory and cognitive systems less affected. Though heritable forms of the disease have been described, the vast majority of cases are sporadic with poorly defined underlying pathogenic mechanisms. Here we demonstrate that the neurological pathology induced in transgenic mice by overexpression of γ-synuclein, a protein not previously associated with ALS, recapitulates key features of the disease, namely selective damage and loss of discrete populations of upper and lower motor neurons and their axons, contrasted by limited effects upon the sensory system
Effect of exogenous xylanase on rumen in vitro gas production and degradability of wheat straw
In Mongolia, the low and seasonal yield of native pastures causes a feed gap between the annual pasture provision and the requirements of grazing ruminants. Therefore, there is a growing need to improve the feeding value of locally available resources such as wheat straw for supplementary feeding. Wheat straw constitutes an important source of roughage for ruminants. It typically contain more than 70% neutral detergent fiber (NDF) on a dry matter (DM) basis, with less than 40% total digestive tract digestibility of the NDF, even under ideal feeding conditions (NRC 2001).The objective of this study was to determine effects of xylanase on in vitro gas production (GP) and in sacco degradability of wheat straw. Rumen fluid was obtained from three Mongolian native goats fitted with permanent rumen cannulas. The trial consisted of five doses (0, 0.5, 1.0, 1.5, 2.0 μL/g of substrate) of a commercial xylanase (Dyadic® xylanase PLUS, Dyadic International, Inc., Jupiter, FL, USA). For the in sacco degradability, different levels of xylanase enzyme were added directly onto 2 g of wheat straw in nylon bags and incubated in the rumen for 3, 6, 12, 24 and 48 h to estimate degradability of wheat straw. Total GP increased (P < 0.001) at all times of incubation at intermediate levels of xylanase. Methane production had a similar pattern at 3 and 12 h of incubation; increased linearly at 24 h of incubation, and was unaffected at 6 and 48 h of incubation. Rumen NH3-N concentration increased linearly at 3 h and the highest values were observed with intermediate enzyme levels. All ruminal volatile fatty acids increased linearly with intermediate levels of the fibrolytic enzyme. The in sacco rate of dry matter degradation decreased linearly (P = 0.020) with increasing enzymes. Intermediate levels of xylanase improved rumen kinetic fermentation and degradability. The outcome of this research indicated that the application of xylanase enzyme could improve in vitro GP fermentation of wheat straw
Orbital Foregrounds for Ultra-Short Duration Transients
Reflections from objects in Earth orbit can produce sub-second, star-like
optical flashes similar to astrophysical transients. Reflections have
historically caused false alarms for transient surveys, but the population has
not been systematically studied. We report event rates for these orbital
flashes using the Evryscope Fast Transient Engine, a low-latency transient
detection pipeline for the Evryscopes. We select single-epoch detections likely
caused by Earth satellites and model the event rate as a function of both
magnitude and sky position. We measure a rate of
sky hour, peaking at , for flashes morphologically
degenerate with real astrophysical signals in surveys like the Evryscopes. Of
these, sky hour are bright enough to be
visible to the naked eye in typical suburban skies with a visual limiting
magnitude of . These measurements place the event rate of orbital
flashes orders of magnitude higher than the combined rate of public alerts from
all active all-sky fast-timescale transient searches, including neutrino,
gravitational-wave, gamma-ray, and radio observatories. Short-timescale orbital
flashes form a dominating foreground for un-triggered searches for fast
transients in low-resolution, wide-angle surveys. However, events like fast
radio bursts (FRBs) with arcminute-scale localization have a low probability
() of coincidence with an orbital flash, allowing optical surveys
to place constraints on their potential optical counterparts in single images.
Upcoming satellite internet constellations, like SpaceX Starlink, are unlikely
to contribute significantly to the population of orbital flashes in normal
operations.Comment: 8 pages, 4 figure
UVUDF: Ultraviolet Imaging of the Hubble Ultradeep Field with Wide-field Camera 3
We present an overview of a 90-orbit Hubble Space Telescope treasury program
to obtain near ultraviolet imaging of the Hubble Ultra Deep Field using the
Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters.
This survey is designed to: (i) Investigate the episode of peak star formation
activity in galaxies at 1<z<2.5; (ii) Probe the evolution of massive galaxies
by resolving sub-galactic units (clumps); (iii) Examine the escape fraction of
ionizing radiation from galaxies at z~2-3; (iv) Greatly improve the reliability
of photometric redshift estimates; and (v) Measure the star formation rate
efficiency of neutral atomic-dominated hydrogen gas at z~1-3. In this overview
paper, we describe the survey details and data reduction challenges, including
both the necessity of specialized calibrations and the effects of charge
transfer inefficiency. We provide a stark demonstration of the effects of
charge transfer inefficiency on resultant data products, which when
uncorrected, result in uncertain photometry, elongation of morphology in the
readout direction, and loss of faint sources far from the readout. We agree
with the STScI recommendation that future UVIS observations that require very
sensitive measurements use the instrument's capability to add background light
through a "post-flash". Preliminary results on number counts of UV-selected
galaxies and morphology of galaxies at z~1 are presented. We find that the
number density of UV dropouts at redshifts 1.7, 2.1, and 2.7 is largely
consistent with the number predicted by published luminosity functions. We also
confirm that the image mosaics have sufficient sensitivity and resolution to
support the analysis of the evolution of star-forming clumps, reaching 28-29th
magnitude depth at 5 sigma in a 0.2 arcsecond radius aperture depending on
filter and observing epoch.Comment: Accepted A
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