Analytic structure of Bloch functions for linear molecular chains

This paper deals with Hamiltonians of the form H=-{\bf \nabla}^2+v(\rr), with v(\rr) periodic along the $z$ direction, $v(x,y,z+b)=v(x,y,z)$. The wavefunctions of $H$ are the well known Bloch functions \psi_{n,\lambda}(\rr), with the fundamental property $\psi_{n,\lambda}(x,y,z+b)=\lambda \psi_{n,\lambda}(x,y,z)$ and $\partial_z\psi_{n,\lambda}(x,y,z+b)=\lambda \partial_z\psi_{n,\lambda}(x,y,z)$. We give the generic analytic structure (i.e. the Riemann surface) of \psi_{n,\lambda}(\rr) and their corresponding energy, $E_n(\lambda)$, as functions of $\lambda$. We show that $E_n(\lambda)$ and $\psi_{n,\lambda}(x,y,z)$ are different branches of two multi-valued analytic functions, $E(\lambda)$ and $\psi_\lambda(x,y,z)$, with an essential singularity at $\lambda=0$ and additional branch points, which are generically of order 1 and 3, respectively. We show where these branch points come from, how they move when we change the potential and how to estimate their location. Based on these results, we give two applications: a compact expression of the Green's function and a discussion of the asymptotic behavior of the density matrix for insulating molecular chains.Comment: 13 pages, 11 figure

Implementation of an enhanced recovery protocol for open and laparoscopic repair of ventral hernia

In the light of introduction of the concept of rapid recovery and the use of miniinvasive methods of treatment of postoperative ventral hernias, laparoscopic herniology attracts more and more attention of practical surgeons. This is due to virtually no wound complications, a reduction of the duration surgery and inpatient stay, which greatly improves social and labor adaptation. Objective. Evaluate the benefits of laparoscopic hernioplasty over the open one in the light of the concept of rapid recovery of ERAS – enhanced recovery after surgery. Materials and methods. For a comparative evaluation in the period from 2015 to 2017, 81 patients with postoperative ventral hernias were examined and surgically treated. According to the methods of hernioplasty, all patients were divided into two groups. The group 1 consisted of 38 (46.91 %) persons who underwent laparoscopic hernioplasty. The group 2 consisted of 43 (53.09 %) persons who underwent "open" allohernioplasty. The multimodal patient management program provided for common elements for both groups aimed at rapid recovery in the postoperative period. Results. The average duration of "open" hernioplasty was (143±25) min, laparoscopic – (98±14) min. The laparoscopic technique of hernioplasty does not require routine drainage of the abdominal cavity. When open allohernioplasty drainage was performed in 72 (69.20 %) cases. 5–6 hours after the surgery, using the "sublay" technique 66 (63.50 %), patients were able to take the vertical position and activate the motor activity within the hospital ward, the rest – during the first day. The postoperative stay in the stanionarium in the group of patients after the "open" hernioplasty was on average (7.98±1.36) days, after the laparoscopic operation – (2.63±1.28) days, respectively. Conclusions. Endovideo-surgical methods for the elimination of primary and postoperative ventral hernias are effective, safe, provide early mobilization of patients and their rapid labor and social adaptation due to a significant smaller number of early and late complications. Restrictions in the use of these treatments are considered to be hernia of a gigantic size, especially postoperative with pronounced joint process and severe concomitant diseases, in which the increase in intraabdominal pressure will be critical and will negatively affect the immediate results of surgical treatment

Gutzwiller density functional theory for correlated electron systems

We develop a new density functional theory (DFT) and formalism for correlated electron systems by taking as reference an interacting electron system that has a ground state wavefunction which obeys exactly the Gutzwiller approximation for all one particle operators. The solution of the many electron problem is mapped onto the self-consistent solution of a set of single particle Schroedinger equations analogous to standard DFT-LDA calculations.Comment: 4 page

Editorial for FGCS Special issue on “Time-critical Applications on Software-defined Infrastructures”

Performance requirements in many applications can often be modelled as constraints related to time, for example, the span of data processing for disaster early warning [1], latency in live event broadcasting [2], and jitter during audio/video conferences [3]. These time constraints are often treated either in an “as fast as possible” manner, such as sensitive latencies in high-performance computing or communication tasks, or in a “timeliness” way where tasks have to be finished within a given window in real-time systems, as classified in [4]. To meet the required time constraints, one has to carefully analyse time constraints, engineer and integrate system components, and optimise the scheduling for computing and communication tasks. The development of a time-critical application is thus time-consuming and costly. During the past decades, the infrastructure technologies of computing, storage and networking have made tremendous progress. Besides the capacity and performance of physical devices, the virtualisation technologies offer effective resource management and isolation at different levels, such as Java Virtual Machines at the application level, Dockers at the operating system level, and Virtual Machines at the whole system level. Moreover, the network embedding [5] and software-defined networking [6] provide network-level virtualisation and control that enable a new paradigm of infrastructure, where infrastructure resources can be virtualised, isolated, and dynamically customised based on application needs. The software-defined infrastructures, including Cloud, Fog, Edge, software-defined networking and network function virtualisation, emerge nowadays as new environments for distributed applications with time-critical application requirements, but also face challenges in effectively utilising the advanced infrastructure features in system engineering and dynamic control. This special issue on “time-critical applications and software-defined infrastructures” focuses on practical aspects of the design, development, customisation and performance-oriented operation of such applications for Clouds and other distributed environments

Resilient Distributed MPC Algorithm for Microgrid Energy Management under Uncertainties

This paper proposes a resilient distributed energy management algorithm able to cope with different types of faults in a DC microgrid system. A distributed optimization method allows to solve the energy management problem without sharing any private data with the network and reducing the computational cost for each agent, with respect to the centralised case. A distributed MPC scheme based on distributed optimization is used to cope with uncertainty that characterizes the microgrid operation. In order to be resilient to faults that limit the amount of power available to consumers, we propose to adaptively store an amount of power in the storage systems to support the loads. A soft constraint on the minimum energy stored in each battery is introduced for feasibility and to cope with persistent faults. The effectiveness of the method is proved by extensive simulation results considering faults on three types of components: renewable generator, distribution grid and communication network

Entanglement, subsystem particle numbers and topology in free fermion systems

We study the relationship between bipartite entanglement, subsystem particle number and topology in a half-filled free fermion system. It is proposed that the spin-projected particle numbers can distinguish the quantum spin Hall state from other states, and can be used to establish a new topological index for the system. Furthermore, we apply the new topological invariant to a disordered system and show that a topological phase transition occurs when the disorder strength is increased beyond a critical value. It is also shown that the subsystem particle number fluctuation displays behavior very similar to that of the entanglement entropy. This provides a lower-bound estimation for the entanglement entropy, which can be utilized to obtain an estimate of the entanglement entropy experimentally.Comment: 14 pages, 6 figure

The use of large language models for marketing content translation and transcreation

Aquesta tesi explora l'ús de grans models de llenguatge per a la transcreació de continguts de màrqueting. Amb els ràpids avenços en el processament del llenguatge natural i l'aparició de models de llenguatge potents com ChatGPT i DeepL, hi ha un interès creixent per utilitzar aquests models per automatitzar el procés de transcreació. Aquest estudi pretén investigar els beneficis, els reptes i les aplicacions potencials dels grans models lingüístics en la transcreació de continguts de màrqueting, examinant el seu impacte en l'eficiència, precisió, creativitat i adaptació cultural.Esta tesis explora el uso de grandes modelos lingüísticos para la transcreación de contenidos de marketing. Con los rápidos avances en el procesamiento del lenguaje natural y la aparición de potentes modelos lingüísticos como ChatGPT y DeepL, cada vez hay más interés en utilizar estos modelos para automatizar el proceso de transcreación. Este estudio pretende investigar las ventajas, los retos y las posibles aplicaciones de los grandes modelos lingüísticos en la transcreación de contenidos de marketing, examinando su impacto en la eficiencia, la precisión, la creatividad y la adaptación cultural.This thesis explores the use of large language models for marketing content transcreation. With the rapid advancements in natural language processing and the emergence of powerful language models like ChatGPT and DeepL, there is a growing interest in using these models to automate the transcreation process. This study aims to investigate the benefits, challenges, and potential applications of large language models in marketing content transcreation, examining their impact on efficiency, accuracy, creativity, and cultural adaptation