Results 71 to 80 of about 878,195 (332)
Spinor algebra and null solutions of the wave equation
, 2010 In this paper we exploit the ideas and formalisms of twistor theory, to show how, on Minkowski space, given a null solution of the wave equation, there are precisely two null directions in $\ker df$, at least one of which is a shear-free ray ...
Baird P. +4 more
core +2 more sources
Null spaces of correlation matrices
Linear Algebra and its Applications, 2003 It is an interesting problem to determine those \(n\times n\) correlation matrices that annihilate a given \(k\)-dimensional subspace of \(\mathbb{R}^n\). (A correlation matrix is real positive definite symmetric with all diagonal elements equal to 1). The solution is known when \(k=n-1\) or \(n-2\). The authors give the complete solution when \(k=n-3\)
Barrett, Wayne, Pierce, Stephen
openaire +2 more sources
Functional Connectivity Linked to Cognitive Recovery After Minor Stroke
Annals of Clinical and Translational Neurology, EarlyView.ABSTRACT Objective Patients with minor stroke exhibit slowed processing speed and generalized alterations in functional connectivity involving frontoparietal cortex (FPC). The pattern of connectivity evolves over time. In this study, we examine the relationship of functional connectivity patterns to cognitive performance, to determine ...
Vrishab Commuri +7 more
wiley +1 more source
On the space of null geodesics of a spacetime: the compact case, Engel geometry and retrievability [PDF]
, 2021 Adrià Marín-Salvador, Roberto Rubio
openalex +1 more source
Annals of Clinical and Translational Neurology, EarlyView.ABSTRACT Objective Super‐Refractory Status Epilepticus (SRSE) is a rare, life‐threatening neurological emergency with unclear etiology in many cases. Mitochondrial dysfunction, often due to disease‐causing genetic variants, is increasingly recognized as a cause, with each gene producing distinct pathophysiological mechanisms.
Pouria Mohammadi +2 more
wiley +1 more source
, 2014 We define and investigate a quantisation of null hypersurfaces in the context of loop quantum gravity on a fixed graph. The main tool we use is the parametrisation of the theory in terms of twistors, which has already proved useful in discussing the ...
Speziale, Simone, Zhang, Mingyi
core +3 more sources
Annals of Clinical and Translational Neurology, EarlyView.ABSTRACT Objective To investigate the value of constructing models based on habitat radiomics and pathomics for predicting the risk of progression in high‐grade gliomas. Methods This study conducted a retrospective analysis of preoperative magnetic resonance (MR) images and pathological sections from 72 patients diagnosed with high‐grade gliomas (52 ...
Yuchen Zhu +14 more
wiley +1 more source
Inverse Kinematics and Control of a 7-DOF Redundant Manipulator Based on the Closed-Loop Algorithm
International Journal of Advanced Robotic Systems, 2011 Closed-loop inverse kinematics (CLIK) algorithm mostly resolves the redundancy at the velocity level. In this paper we extend the CLIK algorithm to the acceleration level to meet some applications that require the joint accelerations.
Jingguo Wang +2 more
doaj
Impact of Asymptomatic Intracranial Hemorrhage on Outcome After Endovascular Stroke Treatment
Annals of Clinical and Translational Neurology, EarlyView.ABSTRACT Background Endovascular treatment (EVT) achieves high rates of recanalization in acute large‐vessel occlusion (LVO) stroke, but functional recovery remains heterogeneous. While symptomatic intracranial hemorrhage (sICH) has been well studied, the prognostic impact of asymptomatic intracranial hemorrhage (aICH) after EVT is less certain ...
Shihai Yang +22 more
wiley +1 more source
Null‐space cognitive precoding for heterogeneous networks
IET Communications, 2014 Small‐cells are considered as an effective solution to increase capacity and offload traffic from, the current macro‐cell cellular system. Owing to the difficulty and costs involved in acquiring new spectrum licenses, small‐cells are expected to coexist with their respective macro‐cells, in the same spectrum.
Castanheira, Daniel +2 more
openaire +2 more sources