112 research outputs found
Nonadiabatic losses from radio-frequency-dressed cold-atom traps: beyond the Landau-Zener model
Nonadiabatic decay rates for a radio-frequency-dressed magnetic trap are calculated using Fermiâs golden rule: that is, we examine the probability for a single atom to make transitions out of the dressed trap and into a continuum in the adiabatic limit, where perturbation theory can be applied. This approach can be compared to the semiclassical Landau-Zener theory of a resonant dressed atom trap, and it is found that, when carefully implemented, the Landau-Zener theory overestimates the rate of nonadiabatic spin-flip transitions in the adiabatic limit. This indicates that care is needed when determining requirements on trap Rabi frequency and magnetic-field gradient in practical atom traps
Current surveillance practices for shedding of elephant endotheliotropic herpesviruses in breeding and bachelor Asian elephant Elephas maximus herds in Europe
Elephant endotheliotropic herpesvirus-haemorrhagic disease (EEHV-HD) is the most common cause of death in juvenile captive Asian elephants Elephas maximus. Currently, weekly whole blood screening is recommended for the detection of viraemia, which occurs prior to the development of clinical disease, but there are no recommendations for monitoring viral shedding into the environment. The aims of this study were to evaluate current EEHV shedding surveillance protocols in Asian elephant herds in Europe, as well as to collate and describe existing EEHV shedding data from these herds. Results from a European Association of Zoos and Aquaria Taxon Advisory Group-approved survey revealed that as of January 2021, 42% of breeding institutions had a protocol for screening for EEHV viraemia, while 30% monitored viral shedding. Shedding data were available from 12 institutions, where a total of 2,863 samples had been collected for polymerase chain reaction (PCR) analysis. Overall, 13.9% of all tested samples were positive for EEHV and 48.9% of elephants tested positive for EEHV. EEHV-1 was both the most common genotype detected and the most commonly tested for. Evidence of the presence of EEHV was reported in 12/12 (100%) of breeding herds. Routine monitoring of EEHV shedding is recommended to enable better understanding of the dynamics of EEHV infection and disease
Retention and loss of PIT tags and surgically implanted devices in the Eurasian beaver
Passive integrated transponder devices (PIT tags) are a valuable tool for individual identification of animals. Similarly, the surgical implantation of transmitters and bio-loggers can provide useful data on animal location, physiology, and behavior. However, to avoid unnecessary recapture and related stress of study animals, PIT tags and bio-loggers should function reliably for long periods of time. Here, we evaluated the retention of PIT tags, and of very high frequency (VHF) transmitters and bio-loggers that were either implanted subcutaneously or into the peritoneal cavity of Eurasian beavers (Castor fiber). Over a 21-year period, we implanted PIT tags in 456 individuals and failed to detect a PIT tag at recapture in 30 cases, consisting of 26 individuals (6% of individuals). In all instances, we were still able to identify the individual due to the presence of unique ear tag numbers and tail scars. Moreover, we implanted 6 VHFs, 36 body temperature loggers and 21 heart rate loggers in 28 individuals, and experienced frequent loss of temperature loggers (at least 6 of 23 recaptured beavers) and heart rate loggers (10 of 18 recaptured beavers). No VHFs were lost in 2 recaptured beavers. Possible causes for PIT tag loss (or non-detection) were incorrect implantation, migration of the tag within the body, a foreign body reaction leading to ejection, or malfunctioning of the tag. We speculate that logger loss was related to a foreign body reaction, and that loggers were either rejected through the incision wound or, in the case of temperature loggers, possibly adhered and encapsulated to intestines, and then engulfed by the gastrointestinal tract and ejected. We discuss animal welfare implications and give recommendations for future studies implanting bio-loggers into wildlife.publishedVersio
Retention and loss of PIT tags and surgically implanted devices in the Eurasian beaver
Background Passive integrated transponder devices (PIT tags) are a valuable tool for individual identification of animals. Similarly, the surgical implantation of transmitters and bio-loggers can provide useful data on animal location, physiology and behavior. However, to avoid unnecessary recapture and related stress of study animals, PIT tags and bio-loggers should function reliably for long periods of time. Here, we evaluated the retention of PIT tags, and of very high frequency (VHF) transmitters and bio-loggers that were either implanted subcutaneously or into the peritoneal cavity of Eurasian beavers (Castor fiber). Results Over a 21-year period, we implanted PIT tags in 456 individuals and failed to detect a PIT tag at recapture in 30 cases, consisting of 26 individuals (6% of individuals). In all instances, we were still able to identify the individual due to the presence of unique ear tag numbers and tail scars. Moreover, we implanted 6 VHFs, 36 body temperature loggers and 21 heart rate loggers in 28 individuals, and experienced frequent loss of temperature loggers (at least 6 of 23 recaptured beavers) and heart rate loggers (10 of 18 recaptured beavers). No VHFs were lost in 2 recaptured beavers. Conclusions Possible causes for PIT tag loss (or non-detection) were incorrect implantation, migration of the tag within the body, a foreign body reaction leading to ejection, or malfunctioning of the tag. We speculate that logger loss was related to a foreign body reaction, and that loggers were either rejected through the incision wound or, in the case of temperature loggers, possibly adhered and encapsulated to intestines, and then engulfed by the gastro-intestinal tract and ejected. We discuss animal welfare implications and give recommendations for future studies implanting bio-loggers into wildlife
APLC-Optimization: an apodized pupil Lyot coronagraph design survey toolkit
We present a publicly available software package developed for exploring
apodized pupil Lyot coronagraph (APLC) solutions for various telescope
architectures. In particular, the package optimizes the apodizer component of
the APLC for a given focal-plane mask and Lyot stop geometry to meet a set of
constraints (contrast, bandwidth etc.) on the coronagraph intensity in a given
focal-plane region (i.e. dark zone). The package combines a high-contrast
imaging simulation package HCIPy with a third-party mathematical optimizer
(Gurobi) to compute the linearly optimized binary mask that maximizes
transmission. We provide examples of the application of this toolkit to several
different telescope geometries, including the Gemini Planet Imager (GPI) and
the High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed.
Finally, we summarize the results of a preliminary design survey for the case
of a 6~m aperture off-axis space telescope, as recommended by the 2020 NASA
Decadal Survey, exploring APLC solutions for different segment sizes. We then
use the Pair-based Analytical model for Segmented Telescope Imaging from Space
(PASTIS) to perform a segmented wavefront error tolerancing analysis on these
solutions.Comment: 17 pages, 16 figures, SPIE conferenc
The Lyot project: toward exoplanet imaging and spectroscopy
Among the adaptive optics systems available to astronomers, the US Air Force Advanced Electro-Optical System (AEOS) is unique because it delivers very high order wave front correction. The Lyot Project includes the construction and installation of the worldâs first diffraction-limited, optimized coronagraph that exploits the full astronomical potential of AEOS and represents a critical step toward the long-term goal of directly imaging and studying extrasolar planets (a.k.a. âexoplanetsâ). We provide an update on the Project, whose coronagraph saw first light in March 2004. The coronagraph is operating at least as well as predicted by simulations, and a survey of nearby stars has begun
Dopamine-Induced Conformational Changes in Alpha-Synuclein
Background: Oligomerization and aggregation of α-synuclein molecules play a major role in neuronal dysfunction and loss in Parkinson's disease [1]. However, α-synuclein oligomerization and aggregation have mostly been detected indirectly in cells using detergent extraction methods [2], [3], [4]. A number of in vitro studies showed that dopamine can modulate the aggregation of α-synuclein by inhibiting the formation of or by disaggregating amyloid fibrils [5], [6], [7]. Methodology/Principal Findings: Here, we show that α-synuclein adopts a variety of conformations in primary neuronal cultures using fluorescence lifetime imaging microscopy (FLIM). Importantly, we found that dopamine, but not dopamine agonists, induced conformational changes in α-synuclein which could be prevented by blocking dopamine transport into the cell. Dopamine also induced conformational changes in α-synuclein expressed in neuronal cell lines, and these changes were also associated with alterations in oligomeric/aggregated species. Conclusion/Significance: Our results show, for the first time, a direct effect of dopamine on the conformation of α-synuclein in neurons, which may help explain the increased vulnerability of dopaminergic neurons in Parkinson's disease
The Lyot project: toward exoplanet imaging and spectroscopy
Among the adaptive optics systems available to astronomers, the US Air Force Advanced Electro-Optical System (AEOS) is unique because it delivers very high order wave front correction. The Lyot Project includes the construction and installation of the worldâs first diffraction-limited, optimized coronagraph that exploits the full astronomical potential of AEOS and represents a critical step toward the long-term goal of directly imaging and studying extrasolar planets (a.k.a. âexoplanetsâ). We provide an update on the Project, whose coronagraph saw first light in March 2004. The coronagraph is operating at least as well as predicted by simulations, and a survey of nearby stars has begun
Girls and Boys Born before 28Â Weeks Gestation: Risks of Cognitive, Behavioral, and Neurologic Outcomes at Age 10Â Years
To compare the prevalence of cognitive, neurological, and behavioral outcomes at 10 years of age in 428 girls and 446 boys who were born extremely preterm (EP)
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