904 research outputs found
Hidden in plain sight:migration routes of the elusive Anadyr bartailed godwit revealed by satellite tracking
Satellite and GPS tracking technology continues to reveal new migration patterns of birds which enables comparative studies of migration strategies and distributional information useful in conservation. Bar-tailed godwits in the East AsianāAustralasian Flyway Limosa lapponica baueri and L. l. menzbieri are known for their long non-stop flights, however these populations are in steep decline. A third subspecies in this flyway, L. l. anadyrensis, breeds in the Anadyr River basin, Chukotka, Russia, and is morphologically distinct from menzbieri and baueri based on comparison of museum specimens collected from breeding areas. However, the non-breeding distribution, migration route and population size of anadyrensis are entirely unknown. Among 24 female bar-tailed godwits tracked in 2015ā2018 from northwest Australia, the main non-breeding area for menzbieri, two birds migrated further east than the rest to breed in the Anadyr River basin, i.e. they belonged to the anadyrensis subspecies. During pre-breeding migration, all birds staged in the Yellow Sea and then flew to the breeding grounds in the eastern Russian Arctic. After breeding, these two birds migrated southwestward to stage in Russia on the Kamchatka Peninsula and on Sakhalin Island en route to the Yellow Sea. This contrasts with the other 22 tracked godwits that followed the previously described route of menzbieri, i.e. they all migrated northwards to stage in the New Siberian Islands before turning south towards the Yellow Sea, and onwards to northwest Australia. Since the Kamchatka Peninsula was not used by any of the tracked menzbieri birds, the 4500 godwits counted in the KhairusovaāBelogolovaya estuary in western Kamchatka may well be anadyrensis. Comparing migration patterns across the three bar-tailed godwits subspecies, the migration strategy of anadyrensis lies between that of menzbieri and baueri. Future investigations combining migration tracks with genomic data could reveal how differences in migration routines are evolved and maintained
ZeroNVS: Zero-Shot 360-Degree View Synthesis from a Single Real Image
We introduce a 3D-aware diffusion model, ZeroNVS, for single-image novel view
synthesis for in-the-wild scenes. While existing methods are designed for
single objects with masked backgrounds, we propose new techniques to address
challenges introduced by in-the-wild multi-object scenes with complex
backgrounds. Specifically, we train a generative prior on a mixture of data
sources that capture object-centric, indoor, and outdoor scenes. To address
issues from data mixture such as depth-scale ambiguity, we propose a novel
camera conditioning parameterization and normalization scheme. Further, we
observe that Score Distillation Sampling (SDS) tends to truncate the
distribution of complex backgrounds during distillation of 360-degree scenes,
and propose "SDS anchoring" to improve the diversity of synthesized novel
views. Our model sets a new state-of-the-art result in LPIPS on the DTU dataset
in the zero-shot setting, even outperforming methods specifically trained on
DTU. We further adapt the challenging Mip-NeRF 360 dataset as a new benchmark
for single-image novel view synthesis, and demonstrate strong performance in
this setting. Our code and data are at http://kylesargent.github.io/zeronvs/Comment: 17 page
Towards Efficient Detection of Small Near-Earth Asteroids Using the Zwicky Transient Facility (ZTF)
We describe ZStreak, a semi-real-time pipeline specialized in detecting
small, fast-moving near-Earth asteroids (NEAs) that is currently operating on
the data from the newly-commissioned Zwicky Transient Facility (ZTF) survey.
Based on a prototype originally developed by Waszczak et al. (2017) for the
Palomar Transient Factory (PTF), the predecessor of ZTF, ZStreak features an
improved machine-learning model that can cope with the data rate
increment between PTF and ZTF. Since its first discovery on 2018 February 5
(2018 CL), ZTF/ZStreak has discovered confirmed new NEAs over a total of
232 observable nights until 2018 December 31. Most of the discoveries are small
NEAs, with diameters less than m. By analyzing the discovery
circumstances, we find that objects having the first to last detection time
interval under 2 hr are at risk of being lost. We will further improve
real-time follow-up capabilities, and work on suppressing false positives using
deep learning.Comment: PASP in pres
Stoichiometry of a regulatory splicing complex revealed by single-molecule analyses
Splicing is regulated by complex interactions of numerous RNA-binding proteins. The molecular mechanisms involved remain elusive, in large part because of ignorance regarding the numbers of proteins in regulatory complexes. Polypyrimidine tract-binding protein (PTB), which regulates tissue-specific splicing, represses exon 3 of Ī±-tropomyosin through distant pyrimidine-rich tracts in the flanking introns. Current models for repression involve either PTB-mediated looping or the propagation of complexes between tracts. To test these models, we used single-molecule approaches to count the number of bound PTB molecules both by counting the number of bleaching steps of GFP molecules linked to PTB within complexes and by analysing their total emissions. Both approaches showed that five or six PTB molecules assemble. Given the domain structures, this suggests that the molecules occupy primarily multiple overlapping potential sites in the polypyrimidine tracts, excluding propagation models. As an alternative to direct looping, we propose that repression involves a multistep process in which PTB binding forms small local loops, creating a platform for recruitment of other proteins that bring these loops into close proximity
Even-Odd Layer-Dependent Anomalous Hall Effect in Topological Magnet MnBi2Te4 Thin Films
A central theme in condensed matter physics is to create and understand the
exotic states of matter by incorporating magnetism into topological materials.
One prime example is the quantum anomalous Hall (QAH) state. Recently, MnBi2Te4
has been demonstrated to be an intrinsic magnetic topological insulator and the
QAH effect was observed in exfoliated MnBi2Te4 flakes. Here, we used molecular
beam epitaxy (MBE) to grow MnBi2Te4 films with thickness down to 1 septuple
layer (SL) and performed thickness-dependent transport measurements. We
observed a non-square hysteresis loop in the antiferromagnetic state for films
with thickness greater than 2 SL. The hysteresis loop can be separated into two
AH components. Through careful analysis, we demonstrated that one AH component
with the larger coercive field is from the dominant MnBi2Te4 phase, while the
other AH component with the smaller coercive field is from the minor Mn-doped
Bi2Te3 phase in the samples. The extracted AH component of the MnBi2Te4 phase
shows a clear even-odd layer-dependent behavior, a signature of
antiferromagnetic thin films. Our studies reveal insights on how to optimize
the MBE growth conditions to improve the quality of MnBi2Te4 films, in which
the QAH and other exotic states are predicted.Comment: 23 pages, 4 figures, comments are welcom
Using Patchxpress to Screen Blockers of the Cardiac Sodium Channel (Nav1.5) for Effects on Late INA, Peak INA, and Channel Kinetics
A proof-of-concept study on endoscopic ultrasound-guided biopsy of detrusor muscle in porcine bladders
IntroductionConventionally, we rely on transurethral resection of bladder tumour (TURBT) for local staging of muscle-invasive bladder cancer (MIBC). However, the procedure is limited by its staging inaccuracy which may delay the definitive treatment of MIBC.MethodsWe conducted a proof-of concept study on endoscopic ultrasound (EUS)-guided biopsy of detrusor muscle in porcine bladders. Five porcine bladders were used in this experiment. Upon EUS, four layers of tissue including the mucosa (hypoechoic), submucosa (hyperechoic), detrusor muscle (hypoechoic) and serosa (hyperechoic) could be identified.ResultsA total of 37 EUS-guided biopsies were taken from 15 sites (three sites per bladder), and the mean number of biopsies taken from each site was 2.47Ā±0.64. Among the 37 biopsies, 30 of them (81.1%) obtained detrusor muscle in the biopsy specimen. For the per biopsy site analysis, detrusor muscle was obtained in 73.3% if only one biopsy was taken, and 100% if two or more biopsies were taken from the same biopsy site. Overall, detrusor muscle was successfully obtained from all 15 biopsy sites (100%). No bladder perforation was observed throughout all biopsy processes.ConclusionEUS-guided biopsy of the detrusor muscle could be performed during the initial cystoscopy session, thus expediting the histological diagnosis and subsequent treatment of MIBC
Caspase-8 and RIP kinases regulate bacteria-induced innate immune responses and cell death
A number of pathogens cause host cell death upon infection, and Yersinia pestis, infamous for its role in large pandemics such as the Black Death in medieval Europe, induces considerable cytotoxicity. The rapid killing of macrophages induced by Y. pestis, dependent upon type III secretion system effector Yersinia outer protein J (YopJ), is minimally affected by the absence of caspase-1, caspase-11, Fas ligand, and TNF. Caspase-8 is known to mediate apoptotic death in response to infection with several viruses and to regulate programmed necrosis (necroptosis), but its role in bacterially induced cell death is poorly understood. Here we provide genetic evidence for a receptor-interacting protein (RIP) kinase-caspase-8-dependent macrophage apoptotic death pathway after infection with Y. pestis, influenced by Toll-like receptor 4-TIR-domain-containing adapter-inducing interferon-Ī² (TLR4-TRIF). Interestingly, macrophages lacking either RIP1, or caspase-8 and RIP3, also had reduced infection-induced production of IL-1Ī², IL-18, TNF, and IL-6; impaired activation of the transcription factor NF-ĪŗB; and greatly compromised caspase-1 processing. Cleavage of the proform of caspase-1 is associated with triggering inflammasome activity, which leads to the maturation of IL-1Ī² and IL-18, cytokines important to host responses against Y. pestis and many other infectious agents. Our results identify a RIP1-caspase-8/RIP3-dependent caspase-1 activation pathway after Y. pestis challenge. Mice defective in caspase-8 and RIP3 were also highly susceptible to infection and displayed reduced proinflammatory cytokines and myeloid cell death. We propose that caspase-8 and the RIP kinases are key regulators of macrophage cell death, NF-ĪŗB and inflammasome activation, and host resistance after Y. pestis infection
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