Search results for "Operator"

Generalized frame operator, lower semiframes, and sequences of translates

2023

Given an arbitrary sequence of elements $\xi =\lbrace \xi _n\rbrace _{n\in \mathbb {N}}$ of a Hilbert space $(\mathcal {H},\langle \cdot ,\cdot \rangle )$, the operator $T_\xi$ is defined as the operator associated to the sesquilinear form $\Omega _\xi (f,g)=\sum _{n\in \mathbb {N}} \langle f , \xi _n\rangle \langle \xi _n , g\rangle$, for $f,g\in \lbrace h\in \mathcal {H}: \sum _{n\in \mathbb {N}}|\langle h , \xi _n\rangle |<^>2<\infty \rbrace$. This operator is in general different from the classical frame operator but possesses some remarkable properties. For instance, $T_\xi$ is always self-adjoint with regard to a particular space, unconditionally defined, and, when xi is a lo…

Modelling of rotations by using matrix solutions of nonlinear wave equations

2007

A family of matrix solutions of nonlinear wave equations is extended and its application to modelling is given. It is shown that a similarity transformation, induced by the matrix solution, is equivalent to the rotation. Matrix solutions are used for modelling helical motions and vortex rings, simultaneous rotations and particles collision, mapping contraction and pulsating spheres. Geometrical interpretation of the doubling of rotation angle in each step of sequential mapping contraction is given. First Published Online: 14 Oct 2010

¿Es necesaria la quimio-radioterapia preoperatoria en todos los pacientes con cáncer del recto localmente avanzado? Análisis de una serie consecutiva…

2013

Antecedentes: actualmente la quimio-radioterapia preoperatoria es el método estándar de tratamiento de los pacientes con cáncer del recto localmente avanzado. Sin embargo, a partir de la estandarización de la técnica de la escisión total del mesorrecto, las recidivas locales se han reducido significativamente y algunos pacientes podrían evitar el sobretratamiento con quimio-radioterapia preoperatoria y su potencial efecto tóxico. El presente estudio ha sido diseñado con el objetivo de evaluar los factores predictivos de recidiva en una serie institucional de pacientes con cáncer rectal estadificado preoperatoriamente con ecografía rectal y/o resonancia magnética como cT2N+ o cT3 y tratados …

Two examples related to conical energies

2022

In a recent article we introduced and studied conical energies. We used them to prove three results: a characterization of rectifiable measures, a characterization of sets with big pieces of Lipschitz graphs, and a sufficient condition for boundedness of nice singular integral operators. In this note we give two examples related to sharpness of these results. One of them is due to Joyce and M\"{o}rters, the other is new and could be of independent interest as an example of a relatively ugly set containing big pieces of Lipschitz graphs.

MR2888559 Muratov, M. A.; Chilin, V. I. (o)-topology in ∗-algebras of locally measurable operators. Ukrainian Math. J. 61 (2009), no. 11, 1798–1808. …

2012

An operatorial approach to stock markets

2009

We propose and discuss some toy models of stock markets using the same operatorial approach adopted in quantum mechanics. Our models are suggested by the discrete nature of the number of shares and of the cash which are exchanged in a real market, and by the existence of conserved quantities, like the total number of shares or some linear combination of cash and shares. The same framework as the one used in the description of a gas of interacting bosons is adopted.

Effectiveness of Leukocyte and Platelet-Rich Fibrin versus Nitrofurazone on Nail Post-Surgery Bleeding and Wound Cicatrization Period Reductions: A R…

2019

Background: Leukocyte and platelet-rich fibrin (L-PRF) may be considered a co-adjuvant intervention that may play a key role in blood coagulation and tissue repair after nail surgeries. The aim of this study was to determine the effectiveness of L-PRF versus nitrofurazone on the post-surgical bleeding and wound cicatrization period in patients with bilateral onychocryptosis during surgeries of chemical matrixectomies with 88% phenol solution. Methods: A randomized single-blind clinical trial was registered with the European Clinical Trials Database (EudraCT) with identification number 2016-002048-18. Twenty healthy participants with bilateral onychocryptosis (n = 40) were recruited and bila…

Can we set quality standards for the centers : minimally invasive surgery vs. open surgery in colorectal cancer resection

2020

Esta comunicación se encuentra disponible en la siguiente URL: https://www.fortunejournals.com/articles/can-we-set-quality-standards-for-the-centers-minimally-invasive-surgery-vs-open-surgery-in-colorectal-cancer-resection.pdf Background: Minimally invasive surgery (MIS) is the standard method for resection of colorectal cancer, but its indications have limitations that are constantly debated. In our study, the center had to meet the following four factors: surgeons should have considerable experience, there should be a high percentage of MIS, a low conversion rate, and good results in the intervention. Methods: Retrospective observational study of a cohort of 948 patients with colorectal c…

La presa in carico dei minori abusanti: ruolo degli operatori e competenze emotive.

2011

Localization of Multi-Class On-Road and Aerial Targets Using mmWave FMCW Radar

2021

mmWave radars play a vital role in autonomous systems, such as unmanned aerial vehicles (UAVs), unmanned surface vehicles (USVs), ground station control and monitoring systems. The challenging task when using mmWave radars is to estimate the accurate angle of arrival (AoA) of the targets, due to the limited number of receivers. In this paper, we present a novel AoA estimation technique, using mmWave FMCW radars operating in the frequency range 77–81 GHz by utilizing the mechanical rotation. Rotating the radar also increases the field of view in both azimuth and elevation. The proposed method estimates the AoA of the targets, using only a single transmitter and receiver. The measurements are…