391 research outputs found
A logic for n-dimensional hierarchical refinement
Hierarchical transition systems provide a popular mathematical structure to
represent state-based software applications in which different layers of
abstraction are represented by inter-related state machines. The decomposition
of high level states into inner sub-states, and of their transitions into inner
sub-transitions is common refinement procedure adopted in a number of
specification formalisms.
This paper introduces a hybrid modal logic for k-layered transition systems,
its first-order standard translation, a notion of bisimulation, and a modal
invariance result. Layered and hierarchical notions of refinement are also
discussed in this setting.Comment: In Proceedings Refine'15, arXiv:1606.0134
Refinement by interpretation in {\pi}-institutions
The paper discusses the role of interpretations, understood as multifunctions
that preserve and reflect logical consequence, as refinement witnesses in the
general setting of pi-institutions. This leads to a smooth generalization of
the refinement-by-interpretation approach, recently introduced by the authors
in more specific contexts. As a second, yet related contribution a basis is
provided to build up a refinement calculus of structured specifications in and
across arbitrary pi-institutions.Comment: In Proceedings Refine 2011, arXiv:1106.348
Estabilidade Local em Problemas de Controle Óptimo com duas variáveis de Estado: Uma Extensão do Teorema de Dockner
O presente trabalho procura demonstrar que as condições exigidas por Dockner no teorema 3, mesmo para o caso da sociedade evidenciar impaciência face ao futuro (caso em que r > 0) podem fazer surgir não só os 4 valores próprios apenas com parte real a que o teorema se refere, como também dois pares de complexos conjugados sendo que dois deles têm parte real positiva e dois parte real negativa. Com isso, as trajectórias em direcção ao estado estacionário, quando vistas a partir do Stable Manifold, podem evoluir em forma de espiral convergente (Foco Estável)
Constraints on Dematerialisation and Allocation of Natural Capital along a Sustainable Growth Path
This paper extends the neoclassical growth model with natural capital by introducing two new concepts: allocation of natural capital and materialization. We consider that anthropogenic environmental impact is correlated with the throughput of the economy (materialisation). Materialisation is the material throughput per unit of economic activity. We capture the effect of the reduction of this throughput dematerialisation in the elasticities of materialisation and aggregate environmental impact. In our framework the fraction of natural capital devoted to production does not provide direct environmental services nor does it contribute to ecosystem functioning namely affecting the carrying capacity of natural capital.We analyse an optimal sustainable growth path, in the context of exogenous technological change. Our main conclusion is that the ratio of dematerialisation elasticities must equal the inverse of the share of natural capital in order to assure unbounded economic growth with constant natural capital
The Montado agroforestry system microclimatic specificity in the context of global change
The effects of oak trees on microclimatic
parameters in Quercus rotundifolia Lam. woodland in the
Alentejo, Southern Portugal, are reported. Results show that
oak tree create a marked differentiation in the grass matrix,
between open and undercanopy areas. Compared to open
areas, it presents lower soil moisture beneath the oak canopy,
lower soil temperatures and lower photosynthetically active
radiation (PAR). Soil temperatures outside trees canopy
were generally higher than undercanopy areas, reaching
twice its values during the winter. The decrease of soil water
content is more rapid in areas outside the trees canopy
action, but the replenishment starts early and is faster in
those areas. PAR intercepted by tree canopy is greater than
60%, and affects dramatically herbaceous production.
Different climatic conditions due to the presence of the tree,
associated with greater variability in chemistry environment
undercanopy, if combined with the IPCC forecasts for
Mediterranean region, pose new challenges in the
management of the montado areas
Alumínio extraível e formas de AL na solução de solos derivados de rocha granitica em Portugal
Extractable aluminium (Al) was determined in surface and subsurface horizons of eleven pedons derived from granite occurring in Portugal, under a wide range of precipitation. Five successive extractions with 1 M KCl, 0.5 M CuCl2 and 0.33 M LaCl3 were used. Monomeric (Alm) and organic (Alorg) forms of Al in the soil solution, extracted at field capacity, were also determined. Amounts of extracted Al were greatest with the 0.5 M CuCl2 and lowest with the 1 M KCl. These amounts showed strong positive correlation with soil organic C contents. Soil horizons having high contents (56-80 g kg-1) of organic C showed the highest amount of extractable Al by the 0.5 M CuCl2 (12.2-30.9 cmolc kg-1). Organically bound Al extracted by the 0.5 M CuCl2 and 0.33 M LaCl3 was also highest in these soils (7.6-10.1 and 4.7-8.3 cmolc kg-1, respectively). In contrast, lowest amounts of Al extracted by the 1 M KCl, 0.5 M CuCl2 and 0.33 M LaCl3 (0.9-4.3, 4.1-17.1 and 2.2-7.2 cmolc kg-1, respectively) were observed in horizons containing low organic C content (3-22 g kg-1). Concentrations of total (AlT), monomeric (Alm) and organic (Alorg) Al in the soil solution of studied soils also increased with increasing soil organic C content, but only Alm was significantly correlated with soil organic C content. Solution of soils having low organic C contents (3-6 g kg-1) showed the lowest concentrations of AlT, Alm and Alorg (0.09-1.60, 0.06-0.38 and 0.03-1.29 μg mL-1, respectively). In contrast, the concentrations of AlT (7.1-17.2 μg mL-1), Alm (0.8-0.9 μg mL-1), and Alorg (7.6-16.9 μg mL-1) were much higher in soils containing high amounts of organic C (37-73 g kg-1). In order to monitor the effects of Al in the soil and quality of sub-superficial water, changes in the concentration of monomeric forms of Al and their activities in the soil solution need further stud
Management control systems use in military defense organizations : a levers of control analysis of the Portuguese Armed Forces
Doutoramento em GestãoA nova gestão pública introduziu o managerialismo, obrigando à adoção de sistemas de controle de gestão para apoio à tomada de decisão, implementação da estratégia e comunicação, enquanto a austeridade governamental e stakeholders exigem eficiência, eficácia, sustentabilidade, transparência e prestação de contas do setor público, organizações de Defesa inclusive.
Os gestores das organizações militares devem explorar os efeitos preditivos dos sistemas de controle de gestão e enfatizar o uso das alavancas de controle para executar a estratégia, identificar estratégias emergentes, permitindo-lhes gerir, promovendo processos que produzem mudanças, para que a estrutura possa seguir a estratégia para alcançar os resultados esperados.
Esta tese é pioneira na investigação do uso de sistemas de controle de gestão em organizações militares. O nosso objetivo principal é o de compreender o uso dos sistemas de controlo de gestão, consubstanciado na evidência empírica dos dados obtidos das perceções do uso das alavancas de controlo de Simons, para responder à questão de investigação: como os gestores militares fazem uso dos sistemas de controlo de gestão para gerir. São estudadas as associações entre o uso das alavancas de controlo de gestão, características individuais, incerteza, aprendizagem organizacional e atenção dos gestores militares, expandindo os estudos no âmbito da teoria da contingência, da teoria do escalão superior, e do modelo das alavancas de controlo de Simons.
A técnica de investigação é exploratória, sendo usada uma plataforma eletrónica na Internet para questionários como instrumento de recolha de dados junto dos gestores militares. A investigação empírica resulta dos dados de 281 questionários realizados em 2021. Os modelos de equações estruturais, por regressão dos mínimos quadrados parciais, foram calculados por software e efetuada análise avançada de múltiplos grupos.
Os resultados são significativos e relevantes, confirmando a complementaridade e interdependência do uso das alavancas de controlo, conforme literatura. O uso das alavancas de controlo pela amostra revela resultados estaticamente significativos que sugerem a existência de condições para identificar novas estratégias, mas também um desenho deficiente dos sistemas de controle de gestão. Os resultados sugerem ainda que os usos dos sistemas de convicções têm efeitos significativos e positivos na aprendizagem organizacional e na atenção dos gestores, sendo esta última enfatizada por todas as alavancas de controlo.
Em relação aos efeitos de moderação das características individuais, verificamos que os gestores militares mais velhos revelam maiores níveis de uso dos controlos interativos, e os formados em economia ou gestão revelam maior propensão para aceitar os princípios da nova gestão pública. Além disso, o uso de controlos interativos pelos gestores militares mais velhos sugerem efeitos positivos na eficiência da sua atenção. A análise com múltiplos grupos sugere que os efeitos da variável idade são significativos e relevantes como moderadores nos proveitos, apoiando a teoria do escalão superior.
Os resultados da investigação sobre como a demografia dos gestores militares influencia o uso das alavancas de controlo contribuem para expandir a teoria das alavancas de controlo de Simons relativamente ao uso dos Sistemas de Controlo de Gestão pelos gestores de militares, e a teoria do escalão superior de Hambricks. A investigação do uso dos Sistemas de Controlo de Gestão em organizações militares pode recorrer à aproximação metodológica do nosso estudo, bem como das nossas conclusões. Também se identificam duas contribuições para os gestores militares gerir as organizações militares. Ao nível estratégico, os decisores das políticas podem desenvolver regulamentos e orientações para mitigar as ameaças e promover os pontos fortes por nós identificados no uso dos Sistemas de Controlo de Gestão pelos gestores militares. Ao nível operacional, os gestores militares podem moderar as decisões de gestão com base nas conclusões identificadas a fim de melhor compreender os seus subordinados, pares e superiores, incrementando a eficiência da comunicação e dos respetivos processos.The new public management introduced managerialism in public sector organizations, compelling management control systems adoption to support decision-making, strategy implementation and communication, while Governmental austerity and State stakeholders demand public sector efficiency, effectiveness, sustainability, transparency, and accountability, including Defence organizations.
The military organizations managers must explore management control systems predictive effects and emphasize the levers of control use to execute the intended strategy and identify emergent strategies, so managers can manage, promoting processes (ways) that produce changes, so structure (means) may follow strategy to achieve the expected outcomes (ends).
This thesis is the first management control systems use research in military organizations. Our main objective is to study management control systems use in military organizations, and support with empiric data Simons’ levers of control use perceptions, to answer the research question how military managers use management control systems in Armed Forces organizations to manage. We investigate the associations between levers of control use, individual’s roles and characteristics, uncertainty, organizational learning, and management attention, expanding Simons’ levers of control framework and contingency approach studies. The methodological choice follows an exploratory approach using an online survey tool, to collect data through an adapted structured questionnaire, targeting military managers. Our empirical research is based on data from 281 cross-sectional survey participations, in 2021. We use partial least squares structural equation modelling software and advanced multigroup analysis to analyze the data.
We find significant and relevant results of levers of control use complementarity, inter-dependency in support of extant literature. The sample perceived levers of control use identify conditions to pursue new strategies, and a poor management control systems design. Our findings suggest that beliefs systems use have significant and positive effects on organizational learning and management attention, being the latter emphasize by all levers of control.
Regarding the individual characteristics’ moderation effects, we find that older military managers reveal higher levels of interactive controls use, and those with economic or management background are more compliant to new public management principles. Furthermore, older military managers results suggests that interactive controls use positively effects management attention efficiency. The multigroup analysis suggests that age variable effects are significant and relevant moderator on outcomes, supporting the upper echelon theory.
Theoretical contributions of our findings expand Simons’ LOC literature management control systems use research to military organizations management, and upper echelon theory, with the study of how military managers demographics influence LOC use. Military organizations management research in management control systems use can build on this approach and conclusions. On the other hand, two main practical contributions are identified. Policy makers may develop regulations or policies to mitigate threats and promote strengths which we identify in military managers management control systems use. Secondly, military managers can moderate their management decisions based on our conclusions to understand their subordinates, peers, and superiors to increase communication and processes efficiency.info:eu-repo/semantics/publishedVersio
Impact of harvest residues, fertilisers and N-fixing plants on growth and nutritional status of young Eucalyptus globulus plantations under Mediterranean conditions
Growth and nutritional status of young plants
of Eucalyptus were assessed in a field trial, under different
scenarios of harvest residue management and nutrient
availability. Treatments were as follows: incorporation of
harvest residues into the soil by harrowing (I); I with N
fertiliser application (IF); I with leguminous, Lupinus
luteus L., seeding (IL); removal of harvest residues (R); R
with N fertiliser application (RF); R with leguminous
seeding (RL); distribution of harvest residues on the soil
surface (S); S with N fertiliser application (SF). Treatments
were replicated four times in four blocks with a fully
randomised design. Tree growth (height and diameter at
breast height) was measured and understory biomass
destructively recorded. Tree nutritional status was assessed
by foliar analysis (N, Ca, Mg, P, K and leaf area). Significant
differences in growth between I, R and S treatments
were only detected at early stage. Intercropping with
Lupinus decreased tree growth during the early phase, but
after 5 years growth was similar to that measured in the I
and R treatments. Application of fertiliser enhanced tree
growth especially when harvest residues were retained on
the soil surface. Combining incorporation of harvest residues
with fertiliser application (IF) was the best option to
increase tree growth, which was significantly greater than
in the R and S. Initially, leaf N was positively affected by
the leguminous (RL and IL), but, after the first fertiliser
application (1 year after planting), greater N was observed in the IF, RF and SF, the difference decreasing gradually
over the following year
Os Solos da República de Cabo Verde - Considerações Gerais sobre o seu Conhecimento
Identificam-se os principais estudos respeitantes à cartografia e à classificação dos solos da
República de Cabo Verde. A partir desses estudos analisam-se as principais características
morfológicas, físicas e químicas, o enquadramento taxonómico e, de forma muito geral, a
distribuição dos solos de Cabo Verde. Consideram-se as principais lacunas a este respeito e
algumas acções a empreender para aumentar o respectivo conhecimento. Finalmente,
definem-se acções fundamentais a desenvolver para a organização funcional da informação
disponível sobre os solos da República de Cabo Verde, tendo em vista o desenvolvimento
agrário, o ordenamento do território, a gestão dos recursos naturais e a qualidade ambiental.Major studies regarding mapping and classification of soils in Cap Verde territory, published
between 1962 and 1987, are identified. Take into account these studies, the main soil physical
and chemical characteristics are highlighted, as well as their taxonomy and distribution. The
main deficiencies are described and actions to deepen its knowledge are identified. Finally,
crucial actions needed for a functional organization of the available information on Cape Verde
soils are outlined, considering territory management, agrarian development, natural resources
management and conservation and environmental quality
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