Berry phases and zero-modes in toroidal topological insulator

An effective Hamiltonian describing the surface states of a toroidal topological insulator is obtained, and it is shown to support both bound-states and charged zero-modes. Actually, the spin connection induced by the toroidal curvature can be viewed as an position-dependent effective vector potential, which ultimately yields the zero-modes whose wave-functions harmonically oscillate around the toroidal surface. In addition, two distinct Berry phases are predicted to take place by the virtue of the toroidal topology.Comment: New version, accepted for publication in EPJB, 6 pages, 1 figur

Towards robotic process automation implementation: an end-to-end perspective

Purpose: Robotic process automation (RPA) seeks to automate business processes, using software robots that interact with systems through their user interface, improving efficiency and reducing costs. However, some critical steps, such as identifying processes suitable for RPA automation, can have a tremendous impact in organizations if a wrong process is selected. Therefore, the purpose of this paper is to provide an approach for analyzing RPA development in business organizations. Design/methodology/approach: This research presents a cohesive literature review about RPA, in order to identify RPA main concepts, which should be reported and considered in all RPA case studies. A model connecting the main elicited RPA concepts is presented as well as its evaluation and applicability grounded of past RPA case study (CS) analysis, using design science research. Findings: The results from this research show that most of the RPA main concepts gathered in the literature review are not reported in the selected RPA CSs. Originality/value: As RPA is a recent topic, literature lacks a synthetization of RPA main topics. This research aims to fill the gap on that, by identifying and synthesize the main topics related to RPA and proposing a model that connects the main RPA concepts, which can be used by researchers as a schema for conducting and writing RPA case studies.info:eu-repo/semantics/acceptedVersio

The role of entrepreneurship on the foundations of dynamic capabilities

This work investigates the antecedents and consequences of dynamic capabilities using data from Portuguese and Brazilian firms. Specifically the influence of entrepreneurship as an opportunity sensing base, the effect on human resources (HR) capability to reach those opportunities, and finally knowledge management (KM) consequences on firm performance. Using a two-country questionnaire, four organisational capabilities are examined, and the link to value creation is established: entrepreneurship capabilities, knowledge management, human resources management capabilities and strategic decision flexibility. The main objective of this research is the operationalisation of a stream of thought on dynamic capabilities. To analyse our model, we have chosen to apply a path analytic technique. This multivariate analysis methodology is regularly used for empirically examining sets of relationships represented in the form of linear causal models, and allows the direct, indirect and total effects. We present the operationalisation of an aggregate construct in this field thus contributing to develop empirical research of dynamic capabilities. Measures were adapted to reflect dynamic decision making. The results show that dynamic capabilities are a complex set of capacities conjugated in sensing, seizing, and reconfiguring processes. Managerial implications for these two countries are discussed.info:eu-repo/semantics/acceptedVersio

Avaliação de fungicidas no controle do mal-das-folhas (Microcyclus ulei) da seringueira, em viveiro.

Objetivando o controle do mal-das-folhas (Microcyclus ulei) da seringueira, foram avaliados, em viveiro, os fungicidas Triadimefon, Carbendazim, Triforine, Dithianon, Tridemorph, nos intervalos de sete a catorze dias. Constatou-se que os fungicidas Triadimefon e Triforine, nas doses e intervalos testados, foram os tratamentos mais eficazes. Carbendazim e Dithianon apresentaram um baixo nivel de eficiencia. Tridemorph foi toxico nas doses utilizadas

Avaliação de fungicidas sistêmicos e protetores e suas misturas, no controle de Microcyclus ulei.

Determinou-se o efeito dos fungicidas sistemicos Triadimefon, Triforine, Benomil e Tiofanato metilico e dos protetores Mancozeb e Clorotalonil aplicados isoladamente ou em mistura (sistemico + protetor) no controle do mal-das-folhas (Microcyclus ulei) da seringueira. Efetuaram-se dois experimentos (em viveiro e em seringal adulto), sendo a aplicacao dos fungicidas feita semanalmente com pulverizador costal de pressao acumulada e atomizador tratorizado. Triadimefon, Triforine, Mancozeb e Clorotalonil, aplicados isoladamente ou em mistura, em dosagens inferiores as convencionais, controlaram a enfermidade

Disorder Induced Localized States in Graphene

We consider the electronic structure near vacancies in the half-filled honeycomb lattice. It is shown that vacancies induce the formation of localized states. When particle-hole symmetry is broken, localized states become resonances close to the Fermi level. We also study the problem of a finite density of vacancies, obtaining the electronic density of states, and discussing the issue of electronic localization in these systems. Our results also have relevance for the problem of disorder in d-wave superconductors.Comment: Replaced with published version. 4 pages, 4 figures. Fig. 1 was revise

Low bone turnover is associated with plain X-ray vascular calcification in predialysis patients

Background Vascular calcification (VC) is a common finding in chronic kidney disease (CKD) patients and predicts subsequent cardiovascular morbidity and mortality in this population. Vascular calcification is linked to disordered mineral metabolism and has been associated with bone histomorphometry changes in CKD. However, data on predialysis patients is scarce. Methods A cross-sectional study was conducted on a cohort of 56 CKD patients not yet on dialysis, who underwent a transiliac bone biopsy for histomorphometric evaluation after double tetracycline labeling. Patients had no previous exposure to calcium salts, vitamin D agents, steroids or bisphosphonates. Vascular calcification was assessed at the time of biopsy, using Kauppila (plain X-ray of the lateral lumbar spine) and Adragão (plain X-ray of the pelvis and hands) scores. Results Vascular calcification was seen in two-thirds of the cohort. Subjects with VC were more likely to be male and have diabetes, and had significantly higher sclerostin and osteoprotegerin circulating levels than those without VC. The histomorphometric analysis showed that bone formation rate was significantly lower in VC compared to non-VC patients. In the multivariable logistic regression analysis, bone formation rate was independently associated with the presence of VC. Conclusions Vascular calcification is highly prevalent in predialysis patients, especially in those with diabetes. The independent association between bone formation rate and VC provides evidence of an important interaction between bone and vessel in CKD. Our results suggest that low bone turnover is a non-traditional risk factor for cardiovascular disease in predialysis patients