Discrete Dynamical Systems: A Brief Survey

Dynamical system is a mathematical formalization for any fixed rule that is described in time dependent fashion. The time can be measured by either of the number systems - integers, real numbers, complex numbers. A discrete dynamical system is a dynamical system whose state evolves over a state space in discrete time steps according to a fixed rule. This brief survey paper is concerned with the part of the work done by José Sousa Ramos [2] and some of his research students. We present the general theory of discrete dynamical systems and present results from applications to geometry, graph theory and synchronization

Confirmation of a crisis leadership model and its effectiveness: lessons from the COVID-19 pandemic

Despite the significance of crisis leadership for organizations, especially in the wake of COVID-19, empirical research in this area is still nascent. Therefore, “What attributes make an effective leader during a crisis?” is unclear. Using lessons learned from the COVID-19 pandemic, this study seeks to address this gap in the literature by i) developing and validating a robust multi-dimensional crisis leadership model and ii) measure its effectiveness in handling the crisis. A higher-order measurement model of crisis leadership comprising of seven constructs (compassion and care, openness and communication, resilience and courage, decisiveness, consultation and collaboration, and empowerment) and two structural models to measure its predictive validity (effectiveness in handling the crisis) were proposed based on the review of crisis leadership literature. Next, using data collected through a global survey, the validity of the proposed models, including the relevance/appropriateness of each construct and the predictive power of the crisis leadership model in explaining the organizations’ effectiveness in handling the crisis, were assessed. The second-order confirmatory factor analysis established the existence of a higher-order measurement model for crisis leadership, with each of the seven constructs contributing uniquely and strongly. The structural equation modeling results confirmed the strong predictive power of the crisis leadership model in explaining the organizations’ effectiveness in handling the crisis across its different (beginning, current, and future) phases. The findings show that crisis leadership is multifaceted and requires an all-encompassing effort and provides a road map for organizations looking to develop crisis leadership capabilities for senior managers and leaders

Modeling the input history of programs for improved instruction-memory performance

When a program is loaded into memory for execution, the relative position of its basic blocks is crucial, since loading basic blocks that are unlikely to be executed first places them high in the instruction-memory hierarchy only to be dislodged as the execution goes on. In this paper we study the use of Bayesian networks as models of the input history of a program. The main point is the creation of a probabilistic model that persists as the program is run on different inputs and at each new input refines its own parameters in order to reflect the program's input history more accurately. As the model is thus tuned, it causes basic blocks to be reordered so that, upon arrival of the next input for execution, loading the basic blocks into memory automatically takes into account the input history of the program. We report on extensive experiments, whose results demonstrate the efficacy of the overall approach in progressively lowering the execution times of a program on identical inputs placed randomly in a sequence of varied inputs. We provide results on selected SPEC CINT2000 programs and also evaluate our approach as compared to the gcc level-3 optimization and to Pettis-Hansen reordering

Optical and Near Infrared Study of the Cepheus E outflow, a very low excitation object

We present images and spectra of the Cepheus E (Cep E) region at both optical and infrared wavelengths. Only the brightest region of the southern lobe of the Cep E outflow reveals optical emission, suggesting that the extinction close to the outflow source plays an important r\^ole in the observed difference between the optical and IR morphologies. Cep E is a unique object since it provides a link between the spectroscopic properties of the optical Herbig-Haro (HH) objects and those of deeply embedded outflows.Comment: Accepted Astron. J., 8 files: paper, tables plus 6 figure

Key performance indicators for improving a CRM implementation

This document analyses the main pros and cons factors in the implementation and configuration of instances of a Customer Relationship Management tool (CRM) in a company, with the purpose of understanding if the establishment of key performance indicators (KPIs) could help achieving a higher success rate in its implantation on a new business.info:eu-repo/semantics/acceptedVersio

Clinical, histological and prognostic features of a novel nail-bed lesion of cats: 41 cases

There is a distinct subset of lesions arising on the digits of cats, located at or close to the nail-bed epithelium, which are typically composed of proliferative fibroblast-like cells, multinucleate giant cells and areas of osseous metaplasia, but currently there is no published literature detailing the clinical or histological features of these lesions. This study identified 41 such cases from two large commercial diagnostic laboratories and assessed various histological and clinical features; 22 cases had additional follow-up data available

Fungal nanotechnology

Due to the outbreak of infectious diseases caused by different pathogenic microorganisms and the development of drug resistance, nanoscale materials have emerged up as novel antimicrobial agents and the well known activity of silver ions and silver-based compounds has promoted research in this field. For this reason, there is an essential need to develop environmentally benign procedures for synthesis of silver nanoparticles for commercialization purposes. In this study, silver nanoparticles were synthesised extracellularly from silver nitrate using the fungi supplied by Micoteca da Universidade do Minho (MUM) fungal culture collection, and the morphology of the nanoparticles was characterised The potential to manipulate key parameters, which control growth and other cellular activities, to achieve an optimised production of nanoparticles were also investigated. In addition, a preliminary study was performed to assess the anti-fungal silver nanoparticles activity against bacteria

Ulcerated Infantile Hemangioma of the Intergluteal Cleft Treated with Topical Timolol

Dados recentes revelam resultados promissores com a utilização de beta-bloqueante tópico no tratamento dos hemangiomas infantis ulcerados. Os autores descrevem o caso clínico de uma lactente pré-termo de 6 meses de idade com um hemangioma infantil ulcerado do sulco interglúteo tratado com bom resultado clínico com timolol tópico

Adubação nitrogenada e posição de amostragem em sistema silvipastoril.

Resumo: O experimento foi desenvolvido para avaliar a produtividade e a morfologia da Brachiaria brizantha cv. Marandu adubada com uréia e sulfato de amônio e em função da posição de amostragem. Foi adotado o esquema de parcelas subdivididas no espaço, sendo a parcela principal constituída por fonte de adubo nitrogenado e a subparcela constituída pela posição de amostragem da braquiária no sub-bosque do sistema silvipastoril no delineamento em blocos casualizados com seis repetições. A adubação nitrogenada e a posição de amostragem podem influenciar a produtividade e a relação F/C da braquiária em sistema silvipastoril. [Nitrogen fertilization and position sampling in silvopastoral system]. Abstract: The experiment was carried to evaluate the yield and morphology of Brachiaria brizantha cv. Marandu fertilized with urea and ammonium sulfate, and depending on the sampling position. A split plot arrangement, with six replicates in the randomized block design, was utilized. The main plot consists of a source of nitrogen fertilizer and sub-plots sampling position of pasture in understory of silvopastoral system. Nitrogen fertilization and sampling position can influence productivity and leaf lamina:stem ratio of Brachiaria in silvopastoral system