Search results for "loop"

Numerical evaluation of NLO multiparton processes

2013

We discuss an algorithm for the numerical evaluation of NLO multiparton processes. We focus hereby on the virtual part of the NLO calculation, i.e. on evaluating the one-loop integration numerically. We employ and extend the ideas of the subtraction method to the virtual part and we use subtraction terms for the soft, collinear and ultraviolet regions, which allows us to evaluate the loop integral numerically in four dimensions. A second ingredient is a method to deform the integration contour of the loop integration into the complex plane. The algorithm is derived on the level of the primitive amplitudes, where we utilise recursive relations to generate the corresponding one-loop off-shell…

Semipredictable dynamical systems

2015

A new class of deterministic dynamical systems, termed semipredictable dynamical systems, is presented. The spatiotemporal evolution of these systems have both predictable and unpredictable traits, as found in natural complex systems. We prove a general result: The dynamics of any deterministic nonlinear cellular automaton (CA) with $p$ possible dynamical states can be decomposed at each instant of time in a superposition of $N$ layers involving $p_{0}$, $p_{1}$,... $p_{N-1}$ dynamical states each, where the $p_{k\in \mathbb{N}}$, $k \in [0, N-1]$ are divisors of $p$. If the divisors coincide with the prime factors of $p$ this decomposition is unique. Conversely, we also prove that $N$ CA w…

NUPR1 works against the metabolic stress-induced autophagy-associated cell death in pancreatic cancer cells.

2013

The incidence of pancreatic adenocarcinoma is increasing with more than 43,000 predicted new cases in the US and 65,000 in Europe this year. Pancreatic cancer patients have a short life expectancy with less than 3–4% 5-y survival, which results in an equivalent incidence and mortality rate. One of the major challenges in pancreatic cancer is the identification of pharmacological approaches that overcome the resistance of this cancer to therapy. Intensive research in the past decades has led to the classification of pancreatic cancers and the identification of the driver key genetic events. Despite the advances in understanding the molecular mechanisms responsible for pancreatic cancer patho…

ultra-short pulse propagation at 160-Gb/s in dispersion managed optical fiber lines

2004

This thesis presents a study on ultra-short pulse propagation at 160-Gb/s in dispersion managed optical fiber lines. In a first part, we describe the experimental design of a SHG-FROG setup able to characterize high repetition rate pulse trains. Secondly, we demonstrate the efficiency of multiple four wave mixing phenomenon for the generation of a 160-GHz pulse train through the compression of a sinusoidal beat-signal. Then, in order to compare the experimental and theoretical results, we present the development of an optical fiber characterization benchtop based on modulational instability. In the last part of this thesis, we built and compare several recirculating loop setups. On the one …

Overview and performance comparison of grid synchronization algorithms

2014

Distributed power generation units are experiencing an impressive growth. Consequently, the amount of energy injected by non-linear loads as power converters is expected to increase. Stability and quality of the overall grid are heavily affected by performances of grid-side converters. In this paper, an overview of grid-synchronization technique is proposed. The grid-side inverter is implemented in MATLAB/Simulink® environment including current control and grid-synchronization section. Both Synchronous Reference Frame (SRF) and Decoupled Double Synchronous Reference Frame (DDSRF) PLL algorithms are implemented. A performance comparison is carried out under ideal and unbalanced utility condi…

The Egan problem on the pull-in range of type 2 PLLs

2021

In 1981, famous engineer William F. Egan conjectured that a higher-order type 2 PLL with an infinite hold-in range also has an infinite pull-in range, and supported his conjecture with some third-order PLL implementations. Although it is known that for the second-order type 2 PLLs the hold-in range and the pull-in range are both infinite, the present paper shows that the Egan conjecture may be not valid in general. We provide an implementation of the third-order type 2 PLL, which has an infinite hold-in range and experiences stable oscillations. This implementation and the Egan conjecture naturally pose a problem, which we will call the Egan problem: to determine a class of type 2 PLLs for …

THE PUBLIC HOSPITAL AS A SYSTEM: FINANCING POLICIES AND THEIR LONG-TERM IMPACT ON THE HEALTH SERVICES PROVIDED

Σκοπός: Οι νέες πολιτικές χρηματοδότησης που υιοθετήθηκαν κατά την περίοδο της οικονομικής ύφεσης συνέβαλαν αναμφισβήτητα στη μείωση των δαπανών του νοσοκομείου, αλλά φαίνεται να είχαν αρνητικό αντίκτυπο για τους ασθενείς και τους εργαζομένους των νοσοκομείων (Economou, Kaitelidou, Karanikolos, & Maresso, 2017; Keramidou & Triantafyllopoulos, 2018; Mitropoulos, Vasileiou, & Mitropoulos, 2018; OECD & European Observatory on Health Systems and Policies, 2019). Η παρούσα ποιοτική μελέτη χρησιμοποιεί τη μέθοδο των δυναμικών συστημάτων (system dynamics) για να αναλύσει και να εξηγήσει τα μακροπρόθεσμα αποτελέσματα των πολιτικών αυτών. Υλικό-Μέθοδος: Δημιουργήθηκε ένα ποιοτικό μον…

Common variants conferring risk of schizophrenia

2009

Schizophrenia is a complex disorder, caused by both genetic and environmental factors and their interactions. Research on pathogenesis has traditionally focused on neurotransmitter systems in the brain, particularly those involving dopamine. Schizophrenia has been considered a separate disease for over a century, but in the absence of clear biological markers, diagnosis has historically been based on signs and symptoms. A fundamental message emerging from genome-wide association studies of copy number variations (CNVs) associated with the disease is that its genetic basis does not necessarily conform to classical nosological disease boundaries. Certain CNVs confer not only high relative ris…

The automated pancreas: A review of technologies and clinical practice

2021

Insulin pumps and glucose sensors are effective in improving diabetes therapy and reducing acute complications. The combination of both devices using an algorithm-driven interoperable controller makes automated insulin delivery (AID) systems possible. Many AID systems have been tested in clinical trials and have proven safety and effectiveness. However, currently, none of these systems are available for routine use in children younger than 6 years in Europe. For continued use, both users and prescribers must have sound knowledge of the features of the individual AID systems. Presently, all systems require various user interactions (e.g. meal announcements) because fully automated systems ar…

A parallel simulated annealing approach to the K shortest loopless paths problem

1997

The k shortest loopless paths problem is a significant combinatorial problem which arises in many contexts. When the size of the networks is very large the exact algorithms fail to find the best solution in a reasonable time. The aim of this paper is to suggest parallel efficient algorithms to obtain a good approximation of the solution to the k shortest loopless paths problem between two arbitrary nodes, when the network size is large. The heuristic used is known in literature as Simulated Annealing. Preliminary tests have been conducted for evaluating the validity of the proposed algorithms. The quality of the obtained results represents a significant base for further experimentations.