Diophantine Approximation and applications in Interference Alignment

This paper is motivated by recent applications of Diophantine approximation in electronics, in particular, in the rapidly developing area of Interference Alignment. Some remarkable advances in this area give substantial credit to the fundamental Khintchine-Groshev Theorem and, in particular, to its far reaching generalisation for submanifolds of a Euclidean space. With a view towards the aforementioned applications, here we introduce and prove quantitative explicit generalisations of the Khintchine-Groshev Theorem for non-degenerate submanifolds of R n. The importance of such quantitative statements is explicitly discussed in Jafar's monograph [12, §4.7.1]

Mechanochemical synthesis of multiferroic yttrium manganite

Multiferroic yttrium manganite (YMnO3) is known as a material that exhibits both ferromagnetic and ferroelectric properties making it interesting for various technological applications. In this work single-phased YMnO3 was prepared for the first time by mechanochemical synthesis in a planetary ball mill. The YMnO3 can be formed directly from the highly activated constituent oxides, Y2O3 and Mn2O3, after 60 min of milling time and subsequently grows during prolonged milling. The cumulative energy introduced into the system during milling for 60 min was 86 kJ/g. X-ray analysis indicates that the as-prepared samples crystallize majority with hexagonal (P63cm) and minorly with orthorhombic (Pnma) YMnO3 structure. The morphology, structure and chemical composition of the powder were investigated by SEM with EDS and TEM. The magnetic properties of the obtained YMnO3 powders were found to change as a function of milling time in a manner consistent with the variation in the nanocomposite microstructure

Information security: Listening to the perspective of organisational insiders

Aligned with the strategy-as-practice research tradition, this article investigates how organisational insiders understand and perceive their surrounding information security practices, how they interpret them, and how they turn such interpretations into strategic actions. The study takes a qualitative case study approach, and participants are employees at the Research & Development department of a multinational original brand manufacturer. The article makes an important contribution to organisational information security management. It addresses the behaviour of organisational insiders – a group whose role in the prevention, response and mitigation of information security incidents is critical. The article identifies a set of organisational insiders’ perceived components of effective information security practices (organisational mission statement; common understanding of information security; awareness of threats; knowledge of information security incidents, routines and policy; relationships between employees; circulation of stories; role of punishment provisions; and training), based on which more successful information security strategies can be developed

Protection of early phase hepatic ischemia-reperfusion injury by cholinergic agonists

BACKGROUND: Cytokine production is critical in ischemia/reperfusion (IR) injury. Acetylcholine binds to macrophages and inhibits cytokine synthesis, through the cholinergic anti-inflammatory pathway. This study examined the role of the cholinergic pathway in cytokine production and hepatic IR- injury. METHODS: Adult male mice underwent 90-min of partial liver ischemia followed by reperfusion. The AChR agonists (1,1-dimethyl-4-phenyl-L-pioperazinium-iodide [DMPP], and nicotine) or saline-vehicle were administered i.p. before ischemia. Plasma cytokine tumor necrosis factor (TNF)-α, macrophage inflammatory protein-2, and Interleukin-6 were measured. Liver injury was assessed by plasma alanine transaminase (ALT) and liver histopathology. RESULTS: A reperfusion time-dependent hepatocellular injury occurred as was indicated by increased plasma-ALT and histopathology. The injury was associated with marked elevation of plasma cytokines/chemokines. Pre-ischemic treatment of mice with DMPP or nicotine significantly decreased plasma-ALT and cytokines after 3 h of reperfusion. After 6 h of reperfusion, the protective effect of DMPP decreased and reached a negligible level by 24 h of reperfusion, despite significantly low levels of plasma cytokines. Histopathology showed markedly diminished hepatocellular injury in DMPP- and nicotine-pretreated mice during the early-phase of hepatic-IR, which reached a level comparable to saline-treated mice at late-phase of IR. CONCLUSION: Pharmacological modulation of the cholinergic pathway provides a means to modulate cytokine production and to delay IR-induced heaptocellular injury

Aplicação da estimulação magnética transcraniana de repetição no tratamento do transtorno obsessivo-compulsivo e outros transtornos de ansiedade

A estimulação magnética transcraniana de repetição (EMTr) vem sendo amplamente investigada como ferramenta terapêutica em transtornos psiquiátricos, especialmente a depressão. Neste trabalho, compilamos as informações provenientes de estudos que investigaram as aplicações da EMTr no tratamento dos transtornos de ansiedade: transtorno do pânico (TP), transtorno de estresse pós-taumático (TEPT), transtorno de ansiedade generalizada (TAG) e especialmente o transtorno obsessivo compulsivo (TOC). Três estudos foram publicados abordando o tratamento do TOC, sendo que utilizaram metodologias e parâmetros de aplicação extremamente diversos, dificultando a obtenção de informações conclusivas sobre a efetividade deste tratamento. Quatro estudos publicados sobre TEPT e EMTr também apresentam dados conflitantes e pouco comparáveis, mas destaca-se publicação recente com desenho duplo-cego e resultados positivos. Quanto ao TP e o TAG, apenas pequenas investigações iniciais foram realizadas. Conclusão: Apesar dos estudos citados, não há dados conclusivos sobre a eficácia terapêutica da EMTr nos transtornos de ansiedade. Isto se dá especialmente devido aos estudos com amostras pequenas e desenho aberto. Portanto, devem ser realizados estudos mais aprofundados para que possamos obter estas respostas.Repetitive transcranial magnetic stimulation (rTMS) have been widely studied as a therapeutic method in psychiatric disorders, specially in major depression. In this paper, we have compiled the information from studies concerning the use of rTMS as a therapeutic tool for anxiety disorders: panic disorder (PD), post-traumattic stress disorder (PTSD), generalized anxiety disorder (GAD) and mainly obsessive-compulsive disorder (OCD).Three studies have been published concerning treatment of OCD with rTMS, but they are very different in their methods and in the application parameters and location, making it difficult to draw any conclusion about the efficacy of rTMS in this cases. Four studies published on PTSD also showed very ambiguous and hardly comparable data, but a recent double-blind study with positive results is discussed. Very few inicial investigations are available concerning PD and GAD. Conclusion: Although many studies are mentioned, thete is no conclusive data about the therapeutic efficacy of rTMS in anxiety disorders. It is mainly due to a large number of open-labelled studies with small sample sizes. Therefore, studies with a deeper approach are needed to provide this answers