Results 1 to 10 of about 42 (42)

Effect of liquid and solid test meals on symptoms and gastric myoelectrical activity in patients with gastroparesis and functional dyspepsia

Neurogastroenterology &Motility, Volume 35, Issue 2, February 2023., 2023
Patients with gastroparesis (GP) and functional dyspepsia (FD) have similar symptoms, but the pathophysiology of symptoms remains uncertain. Results show symptoms and gastric myoelectrical responses after ingestion of solid or liquid test meals are similar and suggests GP and FD are closely related gastric neuromuscular disorders.
Kenneth L. Koch, Mark Van Natta, Henry P. Parkman, Madhusudan Grover, Thomas L. Abell, Richard W. McCallum, Hossam A. Shaltout, Irene Sarosiek, Gianrico Farrugia, Robert J. Shulman, James Tonascia, Laura Miriel, Frank Hamilton, Pankaj J. Pasricha, Gastroparesis Clinical Research Consortium   +14 more
wiley   +1 more source

(α, β)‐Normal Operators in Several Variables

Mathematical Problems in Engineering, Volume 2022, Issue 1, 2022., 2022
We consider an extension of the concept of (α, β)‐normal operators in single variable operator to tuples of operators, similar to those extensions of the concepts of normality to joint normality, hyponormality to joint hyponormality, and quasi‐hyponormality to joint quasi‐hyponormality.
Sid Ahmed Ould Ahmed Mahmoud, Ahmed Himadan Ahmed, Ahmad Sarosh, Maria Patrizia Pera   +3 more
wiley   +1 more source

Spectral Radius Formulas Involving Generalized Aluthge Transform

Journal of Function Spaces, Volume 2022, Issue 1, 2022., 2022
In this paper, we aim to develop formulas of spectral radius for an operator S in terms of generalized Aluthge transform, numerical radius, iterated generalized Aluthge transform, and asymptotic behavior of powers of S. These formulas generalize some of the formulas of spectral radius existing in literature.
Zhiqiang Zhang, Muhammad Saeed Akram, Javariya Hyder, Ghulam Farid, Tao Yan, Muhammed Cinar   +5 more
wiley   +1 more source

Subnormality of Powers of Multivariable Weighted Shifts

Journal of Function Spaces, Volume 2020, Issue 1, 2020., 2020
Given a pair T ≡ (T1, T2) of commuting subnormal Hilbert space operators, the Lifting Problem for Commuting Subnormals (LPCS) asks for necessary and sufficient conditions for the existence of a commuting pair N ≡ (N1, N2) of normal extensions of T1 and T2; in other words, T is a subnormal pair.
Sang Hoon Lee, Woo Young Lee, Jasang Yoon, Nikolai L. Vasilevski   +3 more
wiley   +1 more source

Hyponormality on a Weighted Bergman Space

Journal of Function Spaces, Volume 2020, Issue 1, 2020., 2020
A bounded Hilbert space operator T is hyponormal if T∗T − TT∗ is a positive operator. We consider the hyponormality of Toeplitz operators on a weighted Bergman space. We find a necessary condition for hyponormality in the case of a symbol of the form f+g¯ where f and g are bounded analytic functions on the unit disk.
Houcine Sadraoui, Borhen Halouani, Mubariz T. Garayev, Adel AlShehri, Sivaram K. Narayan   +4 more
wiley   +1 more source

Boundedly Spaced Subsequences and Weak Dynamics

Journal of Function Spaces, Volume 2018, Issue 1, 2018., 2018
Weak supercyclicity is related to weak stability, which leads to the question that asks whether every weakly supercyclic power bounded operator is weakly stable. This is approached here by investigating weak l‐sequential supercyclicity for Hilbert‐space contractions through Nagy–Foliaş–Langer decomposition, thus reducing the problem to the quest of ...
C. S. Kubrusly, P. C. M. Vieira, John R. Akeroyd   +2 more
wiley   +1 more source

On Certain Aspects of the Multidimensional S‐Spectral Theory

Mathematical Problems in Engineering, Volume 2014, Issue 1, 2014., 2014
This paper has two parts. The first one provides the preliminary notions introducing certain general concepts, in order to study, in the second part, the properties of some operator systems which admit spectral residual decompositions, S‐decomposable, S‐spectral, and AS‐scalar systems, and so forth. The results obtained by Frunză, 1975, are generalized,
Cristina Serbanescu, Ioan Bacalu, Kishin Sadarangani   +2 more
wiley   +1 more source

Isomorphic Operators and Functional Equations for the Skew‐Circulant Algebra

Abstract and Applied Analysis, Volume 2014, Issue 1, 2014., 2014
The skew‐circulant matrix has been used in solving ordinary differential equations. We prove that the set of skew‐circulants with complex entries has an idempotent basis. On that basis, a skew‐cyclic group of automorphisms and functional equations on the skew‐circulant algebra is introduced.
Zhaolin Jiang, Tingting Xu, Fuliang Lu, Tongxing Li   +3 more
wiley   +1 more source

On Subscalarity of Some 2 × 2 M‐Hyponormal Operator Matrices

Abstract and Applied Analysis, Volume 2014, Issue 1, 2014., 2014
We provide some conditions for 2 × 2 operator matrices whose diagonal entries are M‐hyponormal operators to be subscalar. As a consequence, we obtain that Weyl type theorem holds for such operator matrices.
Fei Zuo, Junli Shen, Yisheng Song
wiley   +1 more source

On Properties of Class A(n) and n‐Paranormal Operators

Abstract and Applied Analysis, Volume 2014, Issue 1, 2014., 2014
Let n be a positive integer, and an operator T ∈ B(ℋ) is called a class A(n) operator if T1+n2/1+n≥|T|2 and n‐paranormal operator if T1+nx1/1+n≥||Tx|| for every unit vector x ∈ ℋ, which are common generalizations of class A and paranormal, respectively.
Xiaochun Li, Fugen Gao, Changsen Yang
wiley   +1 more source