208 research outputs found
Spikeformer: A Novel Architecture for Training High-Performance Low-Latency Spiking Neural Network
Spiking neural networks (SNNs) have made great progress on both performance
and efficiency over the last few years,but their unique working pattern makes
it hard to train a high-performance low-latency SNN.Thus the development of
SNNs still lags behind traditional artificial neural networks (ANNs).To
compensate this gap,many extraordinary works have been
proposed.Nevertheless,these works are mainly based on the same kind of network
structure (i.e.CNN) and their performance is worse than their ANN
counterparts,which limits the applications of SNNs.To this end,we propose a
novel Transformer-based SNN,termed "Spikeformer",which outperforms its ANN
counterpart on both static dataset and neuromorphic dataset and may be an
alternative architecture to CNN for training high-performance SNNs.First,to
deal with the problem of "data hungry" and the unstable training period
exhibited in the vanilla model,we design the Convolutional Tokenizer (CT)
module,which improves the accuracy of the original model on DVS-Gesture by more
than 16%.Besides,in order to better incorporate the attention mechanism inside
Transformer and the spatio-temporal information inherent to SNN,we adopt
spatio-temporal attention (STA) instead of spatial-wise or temporal-wise
attention.With our proposed method,we achieve competitive or state-of-the-art
(SOTA) SNN performance on DVS-CIFAR10,DVS-Gesture,and ImageNet datasets with
the least simulation time steps (i.e.low latency).Remarkably,our Spikeformer
outperforms other SNNs on ImageNet by a large margin (i.e.more than 5%) and
even outperforms its ANN counterpart by 3.1% and 2.2% on DVS-Gesture and
ImageNet respectively,indicating that Spikeformer is a promising architecture
for training large-scale SNNs and may be more suitable for SNNs compared to
CNN.We believe that this work shall keep the development of SNNs in step with
ANNs as much as possible.Code will be available
Parental Labor Migration and Time Use of Children Left Behind in Rural China
This study examines the relationship between parental migration and children’s time use within the setting of rural China. Through drawing on two large survey datasets and distinguishing between various forms of migration (father-only migration, mother-only migration, and the migration of both parents), I find that having a migrant parent is associated with more domestic work time among left-behind children, particularly for teenage girls with migrant mothers. When mothers are absent, adolescent daughters tend to step into a parenting role, take on additional domestic responsibilities and household tasks that are normally performed by the mothers. As a result, the gender gap in domestic labor increases and the traditional gendered division of labor becomes reinforced among left-behind children. Overall, this paper sheds light on the gendered implications of parental migration, especially maternal migration.Master of Art
A semi-analytical model for estimating total suspended matter in highly turbid waters
Total suspended matter (TSM) is related to water quality. High TSM concentrations limit underwater light availability, thus affecting the primary productivity of aquatic ecosystems. Accurate estimation of TSM concentrations in various waters with remote sensing technology is particularly challenging, as the concentrations and optical properties vary greatly among different waters. In this research, a semi-analytical model was established for Hangzhou Bay and Lake Taihu for estimating TSM concentration. The model construction proceeded in two steps. 1) Two indices of the model were calculated by deriving absorption and backscattering coefficients of suspended matter (ap(λ) and bbp(λ)) from the reflectance signal using a semi-analytical method. 2) The two indices were then weighted to derive TSM. The performance of the proposed model was tested using in situ reflectance and Geostationary Ocean Color Imager (GOCI) data. The derived TSM based on in situ reflectance and GOCI images both corresponded well with the in situ TSM with low mean relative error (32%, 41%), root mean square error (20.1 mg/L, 43.1 mg/L), and normalized root mean square error (33%, 55%). The model was further used for the slightly turbid Xin’anjiang Reservoir to demonstrate its applicability to derive ap(λ) and bbp(λ) in other water types. The results indicated that the form Rrs −1(λ1) − Rrs −1(λ2) could minimize the effect of CDOM absorption in deriving ap(λ) from the total absorption. The model exploited the different relationships between TSM concentration and multiband reflectance, thus improving the performance and application range in deriving TSM
Cost-effectiveness analysis of atezolizumab in patients with non-small-cell lung cancer ineligible for treatment with a platinum-containing regimen: a United Kingdom health care perspective
BackgroundCost-effectiveness of atezolizumab, as a treatment for advanced non-small-cell lung cancer (NSCLC) patients who cannot receive a platinum-containing regimen,was still unknown. Our objective was to evaluate the cost-effectiveness of atezolizumab vs. chemotherapy in this indication from the perspective of UK healthcare system.MethodsFrom the global, randomised, open-label, phase III IPSOS trial, clinical inputs and patient characteristics were obtained. A partitioned survival model with three health states was built: Progression-free survival, progressed disease and death. A lifetime time horizon was applied, with an annual discount rate of 3.5%. Additionally, the willingness-to-pay threshold of £50,000/QALY was utilized. Primary outcomes were quality-adjusted life-year (QALY), costs, and incremental cost-effectiveness ratio (ICER). Sensitivity, scenario, and subgroup analyses were used to assess the reliability of base-case results. Price simulations were carried out in order to provide information for the pricing strategy at specific willingness-to-pay threshold.ResultsIn the base-case analysis, atezolizumab resulted in a gain of 0.28 QALYs and an ICER of £94,873/QALY compared to chemotherapy, demonstrating no cost-effectiveness. Price simulation results revealed that atezolizumab would be preferred at a price lower than £2,215 (a reduction of 41.8%) at the willingness-to-pay threshold of £50,000. Sensitivity, scenario and subgroup analyses revealed these conclusions were generally robust, the model was most sensitive to the price of atezolizumab and subsequent medication. Furthermore, atezolizumab was found to be more cost-effective for patients displaying a positive PD-L1 expression, with an ICER of £72,098/QALY as compared to chemotherapy.ConclusionAtezolizumab is not cost-effective for patients with advanced NSCLC ineligible for platinum-containing regimen, potential price reduction is necessary
Phylogenetic, Expression, and Bioinformatic Analysis of the ABC1
We studied 17 ABC1 genes in Populus trichocarpa, all of which contained an ABC1 domain consisting of about 120 amino acid residues. Most of the ABC1 gene products were located in the mitochondria or chloroplasts. All had a conserved VAVK-like motif and a DFG motif. Phylogenetic analysis grouped the genes into three subgroups. In addition, the chromosomal locations of the genes on the 19 Populus chromosomes were determined. Gene structure was studied through exon/intron organization and the MEME motif finder, while heatmap was used to study the expression diversity using EST libraries. According to the heatmap, PtrABC1P14 was highlighted because of the high expression in tension wood which related to secondary cell wall formation and cellulose synthesis, thus making a contribution to follow-up experiment in wood formation. Promoter cis-element analysis indicated that almost all of the ABC1 genes contained one or two cis-elements related to ABA signal transduction pathway and drought stress. Quantitative real-time PCR was carried out to evaluate the expression of all of the genes under abiotic stress conditions (ABA, CdCl2, high temperature, high salinity, and drought); the results showed that some of the genes were affected by these stresses and confirmed the results of promoter cis-element analysis
PromptStyle: Controllable Style Transfer for Text-to-Speech with Natural Language Descriptions
Style transfer TTS has shown impressive performance in recent years. However,
style control is often restricted to systems built on expressive speech
recordings with discrete style categories. In practical situations, users may
be interested in transferring style by typing text descriptions of desired
styles, without the reference speech in the target style. The text-guided
content generation techniques have drawn wide attention recently. In this work,
we explore the possibility of controllable style transfer with natural language
descriptions. To this end, we propose PromptStyle, a text prompt-guided
cross-speaker style transfer system. Specifically, PromptStyle consists of an
improved VITS and a cross-modal style encoder. The cross-modal style encoder
constructs a shared space of stylistic and semantic representation through a
two-stage training process. Experiments show that PromptStyle can achieve
proper style transfer with text prompts while maintaining relatively high
stability and speaker similarity. Audio samples are available in our demo page
htof::A New Open-source Tool for Analyzing Hipparcos, Gaia, and Future Astrometric Missions
We present htof, an open-source tool for interpreting and fitting the
intermediate astrometric data (IAD) from both the 1997 and 2007 reductions of
Hipparcos, the scanning-law of Gaia, and future missions such as the Nancy
Grace Roman Space Telescope (NGRST). htof solves for the astrometric parameters
of any system for any arbitrary combination of absolute astrometric missions.
In preparation for later Gaia data releases, htof supports arbitrarily
high-order astrometric solutions (e.g. five-, seven-, nine-parameter fits).
Using htof, we find that the IAD of 6617 sources in Hipparcos 2007 might have
been affected by a data corruption issue. htof integrates an ad-hoc correction
that reconciles the IAD of these sources with their published catalog
solutions. We developed htof to study masses and orbital parameters of
sub-stellar companions, and we outline its implementation in one orbit fitting
code (orvara, https://github.com/t-brandt/orvara). We use htof to predict a
range of hypothetical additional planets in the ~Pic system, which could
be detected by coupling NGRST astrometry with Gaia and Hipparcos. htof is pip
installable and available at https://github.com/gmbrandt/htof .Comment: Accepted to AJ. References updated in version 2. The Hipparcos 2007
Re-reduction Java Tool Intermediate Astrometric Data are available at , via
the "zip file" link at https://www.cosmos.esa.int/web/hipparcos/hipparcos-2 :
"...human readable version of the IAD of the Java tool in a zip file
[warning: ~350 MB]...
Isolation, characterization, and genomic analysis of a novel bacteriophage MA9V-1 infecting Chryseobacterium indologenes: a pathogen of Panax notoginseng root rot
Chryseobacterium indologenes is one of the primary causative agents of root rot of Panax notoginseng, which significantly affected plant growth and caused economic losses. With the increasing incidence of antibiotic-resistant bacterial phytopathogens, phage therapy has been garnered renewed attention in treating pathogenic bacteria. However, the therapeutic potential of phage therapy on root rot of P. notoginseng has not been evaluated. In this study, we isolated a novel lytic phage MA9V-1 infecting C. indologenes MA9 from sewage and monitored the formation of clear and round plaques with a diameter of approximately 0.5–1.5 mm. Phage MA9V-1 exhibited rapid absorption (>75% in 8 min), a latency period of 20 min, and a burst size of 10 particles per cell. Transmission electron microscopy indicated that the phage MA9V-1 is a new myovirus hosting C. indologenes MA9. Sequencing of phage genomes revealed that phage MA9V-1 contained a linear double-stranded DNA genome of 213,507 bp with 263 predicted open reading frames, including phage structure, host lysing, and DNA polymerase/helicase but no genes of tRNA, virulence, and antibiotic resistance. Our proteomic tree and genomic analysis revealed that phage MA9V-1 shares identity with Sphingomonas phage PAU and Tenacibaculum phage PTm1; however, they also showed apparent differences. Further systemic evaluation using phage therapy experiments on P. notoginseng suggested that phage MA9V-1 can be a potential candidate for effectively controlling C. indologenes MA9 infection. Thus, we have presented a novel approach to solving root rot in P. notoginseng
orvara::An Efficient Code to Fit Orbits using Radial Velocity, Absolute, and/or Relative Astrometry
We present an open-source Python package, Orbits from Radial Velocity,
Absolute, and/or Relative Astrometry (orvara), to fit Keplerian orbits to any
combination of radial velocity, relative astrometry, and absolute astrometry
data from the Hipparcos-Gaia Catalog of Accelerations. By combining these three
data types, one can measure precise masses and sometimes orbital parameters
even when the observations cover a small fraction of an orbit. orvara achieves
its computational performance with an eccentric anomaly solver five to ten
times faster than commonly used approaches, low-level memory management to
avoid python overheads, and by analytically marginalizing out parallax,
barycenter proper motion, and the instrument-specific radial velocity zero
points. Through its integration with the Hipparcos and Gaia intermediate
astrometry package htof, orvara can properly account for the epoch astrometry
measurements of Hipparcos and the measurement times and scan angles of
individual Gaia epochs. We configure orvara with modifiable .ini configuration
files tailored to any specific stellar or planetary system. We demonstrate
orvara with a case study application to a recently discovered white dwarf/main
sequence (WD/MS) system, HD 159062. By adding absolute astrometry to literature
RV and relative astrometry data, our comprehensive MCMC analysis improves the
precision of HD 159062B's mass by more than an order of magnitude to
. We also derive a low eccentricity and
large semimajor axis, establishing HD 159062AB as a system that did not
experience Roche lobe overflow.Comment: 24 pages, 5 figures, 5 tables. AJ accepted with minor changes. orvara
is available at https://github.com/t-brandt/orvar
Precise Masses and Orbits for Nine Radial Velocity Exoplanets
Radial velocity (RV) surveys have discovered hundreds of exoplanetary systems
but suffer from a fundamental degeneracy between planet mass and orbital
inclination . In this paper we break this degeneracy by combining RVs with
complementary absolute astrometry taken from the Gaia EDR3 version of the
cross-calibrated Hipparcos-Gaia Catalog of Accelerations (HGCA). We use the
Markov Chain Monte Carlo orbit code to simultaneously fit
literature RVs and absolute astrometry from the HGCA. We constrain the orbits,
masses, and inclinations of nine single and massive RV companions orbiting
nearby G and K stars. We confirm the planetary nature of six companions: HD
29021 b (), HD 81040 b
(), HD 87883 b (), HD 98649 b (), HD 106252 b
(), and HD 171238 b
(). We place one companion, HD 196067 b
() on the planet-brown dwarf boundary, and two
companions in the low mass brown dwarf regime: HD 106515 Ab
(), and HD 221420 b
(). The brown dwarf HD 221420 b, with a
semi-major axis of AU, a period of
years, and an eccentricity of
represents a promising target for high-contrast imaging. The RV orbits of HD
87883 b, HD 98649 b, HD 171238 b, and HD 196067 b are not fully constrained yet
because of insufficient RV data. We find two possible inclinations for each of
these orbits due to difficulty in separating prograde from retrograde orbits,
but we expect this will change decisively with future Gaia data releases
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