4,115 research outputs found
Scaling and memory in the return intervals of energy dissipation rate in three-dimensional fully developed turbulence
We study the statistical properties of return intervals between
successive energy dissipation rates above a certain threshold in
three-dimensional fully developed turbulence. We find that the distribution
function scales with the mean return interval as
except for , where the scaling function
has two power-law regimes. The return intervals are short-term and long-term
correlated and possess multifractal nature. The Hurst index of the return
intervals decays exponentially against , predicting that rare extreme
events with are also long-term correlated with the Hurst index
.Comment: 5 pages, 5 figure
SPeC: A Soft Prompt-Based Calibration on Mitigating Performance Variability in Clinical Notes Summarization
Electronic health records (EHRs) store an extensive array of patient
information, encompassing medical histories, diagnoses, treatments, and test
outcomes. These records are crucial for enabling healthcare providers to make
well-informed decisions regarding patient care. Summarizing clinical notes
further assists healthcare professionals in pinpointing potential health risks
and making better-informed decisions. This process contributes to reducing
errors and enhancing patient outcomes by ensuring providers have access to the
most pertinent and current patient data. Recent research has shown that
incorporating prompts with large language models (LLMs) substantially boosts
the efficacy of summarization tasks. However, we show that this approach also
leads to increased output variance, resulting in notably divergent outputs even
when prompts share similar meanings. To tackle this challenge, we introduce a
model-agnostic Soft Prompt-Based Calibration (SPeC) pipeline that employs soft
prompts to diminish variance while preserving the advantages of prompt-based
summarization. Experimental findings on multiple clinical note tasks and LLMs
indicate that our method not only bolsters performance but also effectively
curbs variance for various LLMs, providing a more uniform and dependable
solution for summarizing vital medical information
Direct vs. indirect optical recombination in Ge films grown on Si substrates
The optical emission spectra from Ge films on Si are markedly different from
their bulk Ge counterparts. Whereas bulk Ge emission is dominated by the
material's indirect gap, the photoluminescence signal from Ge films is mainly
associated with its direct band gap. Using a new class of Ge-on-Si films grown
by a recently introduced CVD approach, we study the direct and indirect
photoluminescence from intrinsic and doped samples and we conclude that the
origin of the discrepancy is the lack of self-absorption in thin Ge films
combined with a deviation from quasi-equilibrium conditions in the conduction
band. The latter is confirmed by a simple model suggesting that the deviation
from quasi-equilibrium is caused by the much shorter recombination lifetime in
the films relative to bulk Ge
Electric field-induced creation and directional motion of domain walls and skyrmion bubbles
Magnetization dynamics driven by an electric field could provide long-term
benefits to information technologies because of its ultralow power consumption.
Meanwhile, the Dzyaloshinskii-Moriya interaction in interfacially asymmetric
multilayers consisting of ferromagnetic and heavy-metal layers can stabilize
topological spin textures, such as chiral domain walls, skyrmions, and skyrmion
bubbles. These topological spin textures can be controlled by an electric
field, and hold promise for building advanced spintronic devices. Here, we
present an experimental and numerical study on the electric field-induced
creation and directional motion of topological spin textures in magnetic
multilayer films and racetracks with thickness gradient and interfacial
Dzyaloshinskii-Moriya interaction at room temperature. We find that the
electric field-induced directional motion of chiral domain wall is accompanied
with the creation of skyrmion bubbles at certain conditions. We also
demonstrate that the electric field variation can induce motion of skyrmion
bubbles. Our findings may provide opportunities for developing skyrmion-based
devices with ultralow power consumption.Comment: 26 pages, 6 figure
Wavelength tunable spectral compression in a dispersion-increasing fiber
Adiabatic soliton spectral compression in a dispersion-increasing fiber is
demonstrated both numerically and experimentally. We show a positively-chirped
pulse provides better spectral compression in a dispersion-increasing fiber
with large anomalous dispersion ramp. An experimental spectral compression
ratio of 15.5 is obtained using 350 fs positively-chirped input pulse centered
at 1.5 um. A 30 nm wavelength tuning ability is experimentally achieved.Comment: 3 pages, 4 figures. Submitted 4/03/201
Motor neuron-derived Thsd7a is essential for zebrafish vascular development via the Notch-dll4 signaling pathway.
BackgroundDevelopment of neural and vascular systems displays astonishing similarities among vertebrates. This parallelism is under a precise control of complex guidance signals and neurovascular interactions. Previously, our group identified a highly conserved neural protein called thrombospondin type I domain containing 7A (THSD7A). Soluble THSD7A promoted and guided endothelial cell migration, tube formation and sprouting. In addition, we showed that thsd7a could be detected in the nervous system and was required for intersegmental vessels (ISV) patterning during zebrafish development. However, the exact origin of THSD7A and its effect on neurovascular interaction remains unclear.ResultsIn this study, we discovered that zebrafish thsd7a was expressed in the primary motor neurons. Knockdown of Thsd7a disrupted normal primary motor neuron formation and ISV sprouting in the Tg(kdr:EGFP/mnx1:TagRFP) double transgenic zebrafish. Interestingly, we found that Thsd7a morphants displayed distinct phenotypes that are very similar to the loss of Notch-delta like 4 (dll4) signaling. Transcript profiling further revealed that expression levels of notch1b and its downstream targets, vegfr2/3 and nrarpb, were down-regulated in the Thsd7a morphants. These data supported that zebrafish Thsd7a could regulate angiogenic sprouting via Notch-dll4 signaling during development.ConclusionsOur results suggested that motor neuron-derived Thsd7a plays a significant role in neurovascular interactions. Thsd7a could regulate ISV angiogenesis via Notch-dll4 signaling. Thus, Thsd7a is a potent angioneurin involved in the development of both neural and vascular systems
Mutual Authentication and Key Exchange Protocols for Roaming Services in Wireless Mobile Networks
Ring-Like Solitons in Plasmonic Fiber Waveguide Composed of Metal-Dielectric Multilayers
We design a plasmonic fiber waveguide (PFW) composed of coaxial cylindrical
metal-dielectric multilayers in nanoscale, and constitute the corresponding
dynamical equations describing the modes of propagation in the PFW with the
Kerr nonlinearity in the dielectric layers. The physics is connected to the
discrete matrix nonlinear Schr\"{o}dinger equations, from which the highly
confined ring-like solitons in scale of subwavelength are found both for the
visible light and the near-infrared light in the self-defocusing condition.
Moreover, the confinement could be further improved when increasing the
intensity of the input light due to the cylindrical symmetry of the PFW, which
means both the width and the radius of the ring are reduced.Comment: 4 figures, submitte
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