Throughout mammalian neocortex, layer 5 pyramidal (L5) cells project via the pons to a vast number of cerebellar granule cells (GrCs), forming a fundamental pathway. Yet, it is unknown how neuronal ...dynamics are transformed through the L5→GrC pathway. Here, by directly comparing premotor L5 and GrC activity during a forelimb movement task using dual-site two-photon Ca2+ imaging, we found that in expert mice, L5 and GrC dynamics were highly similar. L5 cells and GrCs shared a common set of task-encoding activity patterns, possessed similar diversity of responses, and exhibited high correlations comparable to local correlations among L5 cells. Chronic imaging revealed that these dynamics co-emerged in cortex and cerebellum over learning: as behavioral performance improved, initially dissimilar L5 cells and GrCs converged onto a shared, low-dimensional, task-encoding set of neural activity patterns. Thus, a key function of cortico-cerebellar communication is the propagation of shared dynamics that emerge during learning.
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•First simultaneous recordings from neocortex and cerebellum over weeks of learning•Cortical layer 5 and cerebellar granule cells show similar task encoding in experts•Learning increases correlations among initially dissimilar L5 and granule cells•L5 and granule cells converge to similar, low-dimensional, task-encoding activity
Simultaneous recordings of ensembles of individual neurons in the neocortex and cerebellum provide a view of how these two brain regions learn together.
We propose new parameterizations for the border and skewness functions appearing in the description of 3D nucleon structure in the language of generalized parton distributions (GPDs). These ...parameterizations are constructed in a way to fulfill the basic properties of GPDs, like their reduction to parton density functions and elastic form factors. They also rely on the power behavior of GPDs in the
x
→
1
limit and the propounded analyticity property of Mellin moments of GPDs. We evaluate compton form factors (CFFs), the sub-amplitudes of the deeply virtual compton scattering (DVCS) process, at the leading order and leading twist accuracy. We constrain the restricted number of free parameters of these new parameterizations in a global CFF analysis of almost all existing proton DVCS measurements. The fit is performed within the PARTONS framework, being the modern tool for generic GPD studies. A distinctive feature of this CFF fit is the careful propagation of uncertainties based on the replica method. The fit results genuinely permit nucleon tomography and may give some insight into the distribution of forces acting on partons.
Triplet carbenes and triplet molecular oxygen can combine to form singlet carbonyl O-oxide Criegee intermediates in an overall spin-allowed transformation. While this reaction runs at the diffusion ...limit in the case of triplet carbenes, singlet carbenes are commonly more reluctant to bind 3O2. In contradiction to this customarily encountered spin selectivity, the σ0π2 singlet ground-state carbene 2H-imidazol-2-ylidene 1 reacts extremely rapidly with 3O2 at temperatures as low as 30 K. The product of this cryogenic reaction is singlet 2H-imidazol-2-one O-oxide 7, an N-heterocyclic Criegee intermediate. The addition reaction becomes possible through the electrophilic activation of dioxygen in the triplet state, in which O2 binding can initially proceed without a barrier. Criegee intermediate 7 exhibits an unprecedented high O–O stretching vibration at 1105 cm–1, which can be explained by a resonance structure with an O2 double bond. Furthermore, 2H-imidazol-2-one 5 and spiro-dioxirane 6 could be identified as the photodecomposition products of the herein-reported carbonyl oxide.
Triplet carbenes and triplet molecular oxygen can combine to form singlet carbonyl
-oxide Criegee intermediates in an overall spin-allowed transformation. While this reaction runs at the diffusion ...limit in the case of triplet carbenes, singlet carbenes are commonly more reluctant to bind
O
. In contradiction to this customarily encountered spin selectivity, the σ
π
singlet ground-state carbene 2
-imidazol-2-ylidene
reacts extremely rapidly with
O
at temperatures as low as 30 K. The product of this cryogenic reaction is singlet 2
-imidazol-2-one
-oxide
, an N-heterocyclic Criegee intermediate. The addition reaction becomes possible through the electrophilic activation of dioxygen in the triplet state, in which O
binding can initially proceed without a barrier. Criegee intermediate
exhibits an unprecedented high O-O stretching vibration at 1105 cm
, which can be explained by a resonance structure with an O
double bond. Furthermore, 2
-imidazol-2-one
and spiro-dioxirane
could be identified as the photodecomposition products of the herein-reported carbonyl oxide.
Collective living systems regularly achieve cooperative emergent functions that individual organisms could not accomplish alone. The rafts of fire ants (Solenopsis invicta) are often studied in this ...context for their ability to create aggregated structures comprised entirely of their own bodies, including tether-like protrusions that facilitate exploration of and escape from flooded environments. While similar protrusions are observed in cytoskeletons and cellular aggregates, they are generally dependent on morphogens or external gradients leaving the isolated role of local interactions poorly understood. Here we demonstrate through an ant-inspired, agent-based numerical model how protrusions in ant rafts may emerge spontaneously due to local interactions. The model is comprised of a condensed structural network of agents that represents the monolayer of interconnected worker ants, which floats on the water and gives ant rafts their form. Experimentally, this layer perpetually contracts, which we capture through the pairwise contraction of all neighboring structural agents at a strain rate of Formula: see text. On top of the structural layer, we model a dispersed, on-lattice layer of motile agents that represents free ants, which walk on top of the floating network. Experimentally, these self-propelled free ants walk with some mean persistence length and speed that we capture through an ant-inspired phenomenological model. Local interactions occur between neighboring free ants within some radius of detection, R, and the persistence length of freely active agents is tuned through a noise parameter, η as introduced by the Vicsek model. Both R and η where fixed to match the experimental trajectories of free ants. Treadmilling of the raft occurs as agents transition between the structural and free layers in accordance with experimental observations. Ultimately, we demonstrate how phases of exploratory protrusion growth may be induced by increased ant activity as characterized by a dimensionless parameter, Formula: see text. These results provide an example in which functional morphogenesis of a living system may emerge purely from local interactions at the constituent length scale, thereby providing a source of inspiration for the development of decentralized, autonomous active matter and swarm robotics.
We extend our model-independent approach for characterising strong gravitational lenses to its most general form to leading order and use the orientation angles of a set of multiple images with ...respect to their connection line(s) in addition to the relative distances between the images, their ellipticities, and time-delays. For two symmetric images that straddle the critical curve, the orientation angle additionally allows us to determine the slope of the critical curve and a second (reduced) flexion coefficient at the critical point on the connection line between the images. It also allows us to drop the symmetry assumption that the axis of largest image extension is orthogonal to the critical curve. For three images almost forming a giant arc, the degree of assumed image symmetry is also reduced to the most general case, describing image configurations for which the source need not be placed on the symmetry axis of the two folds that unite at the cusp. For a given set of multiple images, we set limits on the applicability of our approach, show which information can be obtained in cases of merging images, and analyse the accuracy achievable due to the Taylor expansion of the lensing potential for the fold case on a galaxy cluster scale Navarro-Frenk-White-profile, a fold and cusp case on a galaxy cluster scale singular isothermal ellipse, and compare the generalised approach with our previously published one. The position of the critical points is reconstructed with less than 5′′ deviation for multiple images closer to the critical points than 30% of the (effective) Einstein radius. The slope of the critical curve at a fold and its shape in the vicinity of a cusp deviate less than 20% from the true values for distances of the images to the critical points less than 15% of the (effective) Einstein radius.
This article reviews the recent literature on ex post evaluation of the impacts of the
European Union (EU) Emissions Trading Scheme (ETS) on regulated firms in the industrial
and power sectors. We ...summarize the findings from original research papers concerning
three broadly defined impacts: carbon dioxide emissions, economic performance and
competitiveness, and innovation. We conclude by highlighting gaps in the current
literature and suggesting priorities for future research on this landmark policy. (
JEL: Q52, Q54, Q58)
We hypothesized that different phases of intraoperative hypotension should be differentiated because of different underlying causative mechanisms. We defined post-induction hypotension (PIH; i.e. ...arterial hypotension occurring during the first 20 min after anaesthesia induction) and early intraoperative hypotension (eIOH; i.e. arterial hypotension during the first 30 min of surgery).
In this retrospective study, we included 2037 adult patients who underwent general anaesthesia. Arterial hypotension was defined as a systolic arterial blood pressure (SAP) <90 mm Hg or a need for norepinephrine infusion at > 6 µg min−1 at least once during the phases of PIH and eIOH. Multivariate logistic regression analysis was used to test for association of clinical factors with PIH and eIOH.
Independent variables significantly related to PIH were pre-induction SAP odds ratio (OR) 0.97 (95% confidence interval 0.97–0.98), age OR 1.03 (1.02–1.04), and emergency surgery OR 1.75 (1.20–2.56); P<0.01 each. Pre-induction SAP OR 0.99 (0.98–0.99), P<0.01, age OR 1.02 (1.02–1.03), P<0.01, emergency surgery OR 1.83 (1.28–2.62), P<0.01, supplementary administration of spinal or epidural anaesthetic techniques OR 3.57 (2.41–5.29), P<0.01, male sex OR 1.41 (1.12–1.79), P<0.01, and ASA physical status IV OR 2.18 (1.19–3.99), P=0.01 were significantly related to eIOH.
We identified clinical factors associated with PIH and eIOH. The use of these factors to estimate the risk of PIH and eIOH might allow the avoidance or timely treatment of hypotensive episodes during general anaesthesia.
Products of Criegee intermediate (CI) chemistry were recently detected in radical chain autoxidation reactions involving β-hydroxyperoxy radicals. Here, we demonstrate by means of accurate G4 ...computations that direct scission of the latter to CIs and radical byproducts is thermodynamically highly unfavorable. Instead, the reaction becomes possible through a hydrogen abstraction reaction that could proceed by reversible formation of a dimeric tetroxide and a subsequent 1,6 hydrogen shift of the hydroxy hydrogen.
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