Graded identities of block-triangular matrices

Let $F$ be an infinite field and $UT(d_1,\dots, d_n)$ be the algebra of upper block-triangular matrices over $F$. In this paper we describe a basis for the $G$-graded polynomial identities of $UT(d_1,\dots, d_n)$, with an elementary grading induced by an $n$-tuple of elements of a group $G$ such that the neutral component corresponds to the diagonal of $UT(d_1,\dots,d_n)$. In particular, we prove that the monomial identities of such algebra follow from the ones of degree up to $2n-1$. Our results generalize for infinite fields of arbitrary characteristic, previous results in the literature which were obtained for fields of characteristic zero and for particular $G$-gradings. In the characteristic zero case we also generalize results for the algebra $UT(d_1,\dots, d_n)\otimes C$ with a tensor product grading, where $C$ is a color commutative algebra generating the variety of all color commutative algebras.Comment: 24 pages and 39 references. We have added section 5 in the text about tensor products by color commutative superalgebra

Citizens’ Freedom to Choose Representatives: Ballot Structure, Proportionality and “Fragmented” Parliaments

The analysis of the political consequences of electoral laws has emphasized how individual characteristics of the electoral system (electoral formulas, district magnitude, ballot structure) affect the degree of parliament “fragmentation” and proportionality. This paper argues that the personal attributes of representatives are also an important consequence of electoral laws, and that they are in part determined by citizens’ freedom to choose representatives. We clarify this concept and develop an index of citizens’ freedom to choose members of parliament as a function of the ballot structure, district size and electoral formulae. Using data from twenty nine countries, we find that neither proportionality nor the effective number of parties is significantly affected by voters’ freedom of choice. This result has important normative implications for electoral reform.Ballot structure; Electoral index; Freedom to choose; Personal vote.

Operational risk management: the basel II

This work shows the operational risk management and the importance of implementing an appropriate structure of risk management. In order to contextualize the issue was addressed the concept of risk and operational risk and the various risk categories and made the frame in the various Basel Accords. It focused on Basel II that has innovated dealing with operational risk, hitherto forgotten. In this context it was discussed the various risk assessment methods: basic, standard and advanced. The theme is organized so that there is a common thread that culminates in risk management presenting the guidelines of the BIS in this regard and a model of a risk management framework.N/

Effect of dithiocarbamate thiram on Wistar rat growth plate and articular cartilage

Avaliou-se o efeito do tirame, ditiocarbamato largamente utilizado na agricultura como antifúngico e repelente de roedores, na ossificação endocondral de mamíferos, usando, como modelo, ratos Wistar. Não foram observadas lesões na cartilagem articular, nem nas placas de crescimento, o que pode ser atribuído à dose utilizada e à duração do ensaio. A diminuição da altura da placa de crescimento nos animais aos quais foi administrado o tirame parece traduzir o atraso verificado no crescimento em geral, e não um efeito específico na cartilagem, uma vez que as diferentes zonas da placa epifisária mantiveram as proporções dos animais do grupo-controle. Embora não tenham sido verificados, no presente trabalho, os efeitos registrados para outras espécies nos tecidos cartilaginosos, sugere-se a avaliação dos efeitos crónicos do tirame no crescimento e no desenvolvimento dos ossos longos em mamíferos

Positron emission tomography in the detection of occult primary head and neck carcinoma: a retrospective study

BACKGROUND: The management of cervical lymph node metastases from an unknown primary tumor remains a controversial subject. Recently, Positron Emission Tomography (PET) has proved useful in the detection of these tumors, even after an unsuccessful conventional diagnostic workup. This study was performed to assess the role of PET in the detection of occult primary head and neck carcinomas. METHODS: A retrospective analysis of a four year period at a tertiary referral oncology hospital was conducted. RESULTS: Of the 49 patients with cervical metastases of carcinoma from an unknown primary, PET detected a primary in 9 patients and gave 5 false positive and 4 false negative results. Detection rate, sensitivity, specificity and accuracy were of 18.4%, 69.2%, 86.1% and 81.6%, respectively. PET was also of substantial benefit in detecting distant metastatic disease and, thus, altered therapeutic strategies in a significant amount of patients. CONCLUSIONS: Therefore, PET is a valuable tool in the management of patients with occult primary head and neck carcinoma, not only because it provides additional information as to the location of primary tumors, but also due to the fact that it can detect unexpected distant metastase

Dove in the skin cleansing category case study : do private labels represent a threat?

During the past years, the Portuguese retail mass market had been witnessing some changes in the consumers shopping habits. There are several reasons that might explain this fact. One of the main reasons for this phenomenon is the financial crisis, forcing consumers to change some of their habits. Over the years the retail mass market has been changing and adapting to new trends. In general, brands are enlarging their product portfolios in order to face competition and to try to reach every consumer segment – decreasing the product differentiation. Brands are now challenged to stand out in categories where sometimes products’ benefits are very alike. Given the decrease in product differentiation and the Portuguese consumer adaptation to the economic environment, the number of private labels purchased has been increasing. As a consequence, the variation in the perceived quality between NBs and PLBs is decreasing, resulting into the use of price as the deciding factor. Despite the veracity of price being the ultimate deciding factor in some categories (such as food), in the skin cleansing category the same cannot be concluded. As a market leader in the category, Dove represents an example of success in an industry where wining a price war is crucial. This research tries to unveil some of reasons behind this success. Much of the success is due to the nature of each category. This nature will vary according to variables such as risk of purchase, price consciousness and others which will lead to a higher propensity towards national brands.Ao longo dos últimos anos, o mercado de retalho português para as massas tem vindo a presenciar as mudanças nos hábitos de compras dos consumidores. Existem várias razões que podem explicar este facto. Uma das principais razões para este fenómeno é a crise financeira, forçando os consumidores a mudar os seus hábitos. Durante estes anos, o mercado de retalho tem vindo a mudar e a adaptar-se às novas tendências. Num modo geral, as marcas estão a reagir à concorrência ao alargarem os seus portfólios e ao tentarem atingir todos os segmentos – o que resulta numa diminuição de diferenciação de produto. As marcas são agora desafiadas a destacarem-se em categorias onde, por vezes, os benefícios entre produtos são semelhantes. Dada a diminuição na diferenciação de produto e dada a adaptação do consumidor português à conjuntura económica, o número de vendas de marca própria tem vindo a aumentar. Como consequência, a variação na perceção da qualidade entre marcas privadas e marcas próprias está a diminuir, o que leva os consumidores a usarem o preço como fator de decisão. Apesar da veracidade da afirmação de que o preço é o fator decisivo em algumas categorias (como a alimentação), na categoria de skin cleansing o mesmo não poder ser concluído. Como líder de mercado na categoria, Dove representa um exemplo de sucesso numa indústria onde ganhar a guerra de preços é crucial. Este estudo tenta revelar algumas das razões por detrás deste sucesso. Grande parte do sucesso é derivada da natureza de cada categoria. Esta natureza irá variar consoante variáveis como o risk of purchase, price consciousness, entre outras, o que leva a uma maior propensão para a compra de marcas privadas. Palavras-chave: marcas brancas; cuidado pessoal; mercado de retalho; comportamento do consumidor; mercado de massas; limpeza de pele