757 research outputs found
Spatial gene drives and pushed genetic waves
Gene drives have the potential to rapidly replace a harmful wild-type allele
with a gene drive allele engineered to have desired functionalities. However,
an accidental or premature release of a gene drive construct to the natural
environment could damage an ecosystem irreversibly. Thus, it is important to
understand the spatiotemporal consequences of the super-Mendelian population
genetics prior to potential applications. Here, we employ a reaction-diffusion
model for sexually reproducing diploid organisms to study how a locally
introduced gene drive allele spreads to replace the wild-type allele, even
though it possesses a selective disadvantage . Using methods developed by
N. Barton and collaborators, we show that socially responsible gene drives
require , a rather narrow range. In this "pushed wave" regime, the
spatial spreading of gene drives will be initiated only when the initial
frequency distribution is above a threshold profile called "critical
propagule", which acts as a safeguard against accidental release. We also study
how the spatial spread of the pushed wave can be stopped by making gene drives
uniquely vulnerable ("sensitizing drive") in a way that is harmless for a
wild-type allele. Finally, we show that appropriately sensitized drives in two
dimensions can be stopped even by imperfect barriers perforated by a series of
gaps
Covering properties in countable products, II
summary:In this paper, we discuss covering properties in countable products of Čech-scattered spaces and prove the following: (1) If is a perfect subparacompact space and is a countable collection of subparacompact Čech-scattered spaces, then the product is subparacompact and (2) If is a countable collection of metacompact Čech-scattered spaces, then the product is metacompact
CORNN: Convex optimization of recurrent neural networks for rapid inference of neural dynamics
Advances in optical and electrophysiological recording technologies have made
it possible to record the dynamics of thousands of neurons, opening up new
possibilities for interpreting and controlling large neural populations in
behaving animals. A promising way to extract computational principles from
these large datasets is to train data-constrained recurrent neural networks
(dRNNs). Performing this training in real-time could open doors for research
techniques and medical applications to model and control interventions at
single-cell resolution and drive desired forms of animal behavior. However,
existing training algorithms for dRNNs are inefficient and have limited
scalability, making it a challenge to analyze large neural recordings even in
offline scenarios. To address these issues, we introduce a training method
termed Convex Optimization of Recurrent Neural Networks (CORNN). In studies of
simulated recordings, CORNN attained training speeds ~100-fold faster than
traditional optimization approaches while maintaining or enhancing modeling
accuracy. We further validated CORNN on simulations with thousands of cells
that performed simple computations such as those of a 3-bit flip-flop or the
execution of a timed response. Finally, we showed that CORNN can robustly
reproduce network dynamics and underlying attractor structures despite
mismatches between generator and inference models, severe subsampling of
observed neurons, or mismatches in neural time-scales. Overall, by training
dRNNs with millions of parameters in subminute processing times on a standard
computer, CORNN constitutes a first step towards real-time network reproduction
constrained on large-scale neural recordings and a powerful computational tool
for advancing the understanding of neural computation.Comment: Accepted at NeurIPS 202
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