The spectral characterisation of reduced order models in chemical kinetic systems

The size and complexity of multi-scale problems such as those arising in chemicalkinetics mechanisms has stimulated the search for methods that reduce the numberof species and chemical reactions but retain a desired degree of accuracy. The time-scale characterisation of the multi-scale problem can be carried out on the basis oflocal information such as the Jacobian matrix of the model problem and its relatedeigen-system evaluated at one pointPof the system trajectory. While the originalproblem is usually described by ordinary differential equations (ODEs), the reducedorder model is described by a reduced number of ODEs and a number of algebraicequations (AEs), that might express one or more physical conservation laws (mass,momentum, energy), or the fact that the long-term dynamics evolves within a so-calledSlow Invariant Manifold (SIM). To fully exploit the benefits offered by a reduced ordermodel, it is required that the time scale characterisation of then-dimensional reducedorder model returns an answer consistent and coherent with the time-scale characteri-sation of theN-dimensional original model. This manuscript discusses a procedure forobtaining the time-scale characterisation of the reduced order model in a manner thatis consistent with that of the original problem. While a standard time scale characteri-sation of the (original)N-dimensional original model can be carried out by evaluatingthe eigen-system of the (N×N) Jacobian matrix of the vector field that defines thesystem dynamics, the time-scale characterisation of then-dimensional reduced ordermodel (withn<N) can be carried out by evaluating the eigen-system of a (n×n)con-strainedJacobian matrix,JC, of the reduced vector field that accounts for the role ofthe constraints.info:eu-repo/semantics/publishe

Biologia comparada de Spodoptera cosmioides (Walk.) (Lepidoptera: Noctuidae) em cebola, mamona, soja e feijão Compared biology of Spodoptera cosmioides (Walk.) (Lepidoptera: Noctuidae) in onion, castor oil plant, soybean and bean

Estudou-se a biologia de Spodoptera cosmioides (Walk.) sobre quatro hospedeiros naturais (folhas de cebola, mamona, soja cv. Embrapa 48 e feijão cv. Carioca). Foram avaliados a duração e viabilidade das fases imaturas e do ciclo total, número de ínstares, peso de pupas, razão sexual, porcentagem de deformação de adultos e de adultos não liberados dos invólucros pupais, longevidade de adultos, fecundidade e viabilidade de ovos. Observou-se menor duração e maior viabilidade do período ovo-adulto para mamona e cebola (39,7 dias e 21,7% e 40,5 dias e 21,8%, respectivamente), do que para soja (46,0 dias e 3,9%). O peso pupal foi de 444,6 mg em cebola, 420,0 em feijão, 396,6 em mamona e 298,7 em soja. Constatou-se um predomínio de seis ínstares larvais em folhas de cebola e mamona, ocorrendo também sete para alguns indivíduos, enquanto que em soja predominou a ocorrência de sete, também verificando oito ínstares, indicando uma menor adequação nutricional deste hospedeiro. As fêmeas apresentaram duração da fase pupal significativamente menor do que os machos em todos hospedeiros, fazendo com que a emergência do adulto ocorresse antes dos machos. Em cebola, a longevidade de adultos foi significativamente superior aos demais hospedeiros. A fecundidade foi maior em cebola e mamona (3224 e 3206 ovos/fêmea, respectivamente), enquanto que para soja observou-se 1353 ovos/fêmea. Em folhas de feijão, o desenvolvimento do inseto foi prejudicado por caracteres morfológicos - pilosidade, que promoveram elevada mortalidade na fase larval.<br>The biology of Spodoptera cosmioides (Walk.) was studied on four natural hosts (onion leaves, castor oil plant, soy cv. Embrapa 48 and bean cv. Carioca). The duration and viability of immature phases and total cycle, instar number, pupals weight, sexual ratio, percentage of deformed adults and adults not released of pupal beg, adults' longevity, fecundity and eggs viability were evaluated. It was observed in castor oil plant and onion shorter duration and larger viability of total cycle (39.7 days and 21.7%; 40.5 days and 21.8%, respectively), in contrast of soy (46.0 days and 3.9%). The pupal weight was 444.6 mg on onion, 420.0mg on bean, 396.6mg on castor oil plant and 298.7 mg on soy. Onion and castor oil plant leaves had a predominance of six larval instars, also happening seven for some of them, while in soy the occurrence of seven prevailed, also happening eight instars, indicating less nutritional adaptation of this host. The females had pupal phase significantly smaller than the males in all the hosts, making adults emergency happen before the males. In onion, the longevity of the adults was significantly superior comparing with the other hosts. The fecundity was better on onion and castor oil plant (3224 and 3206 eggs/female, respectively), therefore on soy was observed 1353 eggs/female. In bean leaves, the development of the insect was harmed by morphologic characters, which promoted high mortality in the larval phase

The longest path problem is polynomial on cocomparability graphs

The longest path problem is the problem of finding a path of maximum length in a graph. As a generalization of the Hamiltonian path problem, it is NP-complete on general graphs and, in fact, on every class of graphs that the Hamiltonian path problem is NP-complete. Polynomial solutions for the longest path problem have recently been proposed for weighted trees, ptolemaic graphs, bipartite permutation graphs, interval graphs, and some small classes of graphs. Although the Hamiltonian path problem on cocomparability graphs was proved to be polynomial almost two decades ago [9], the complexity status of the longest path problem on cocomparability graphs has remained open until now; actually, the complexity status of the problem has remained open even on the smaller class of permutation graphs. In this paper, we present a polynomial-time algorithm for solving the longest path problem on the class of cocomparability graphs. Our result resolves the open question for the complexity of the problem on such graphs, and since cocomparability graphs form a superclass of both interval and permutation graphs, extends the polynomial solution of the longest path problem on interval graphs [18] and provides polynomial solution to the class of permutation graphs

Molecular effects of the ubiquitous diatom Skeletonema marinoi on the copepods Calanus helgolandicus

We introduces the umodules, a generalisation of the notion of graph module. The theory we develop captures among others undirected graphs, tournaments, digraphs, and $2-$structures. We show that, under some axioms, a unique decomposition tree exists for umodules. Polynomial-time algorithms are provided for: non-trivial umodule test, maximal umodule computation, and decomposition tree computation when the tree exists. Our results unify many known decomposition like modular and bi-join decomposition of graphs, and a new decomposition of tournaments.Comment: Soumis \`a ISAAC 200

Leadership and management in UK medical school curricula

Purpose Although medical leadership and management (MLM) is increasingly being recognised as important to improving healthcare outcomes, little is understood about current training of medical students in MLM skills and behaviours in the UK. The paper aims to discuss these issues. Design/methodology/approach This qualitative study used validated structured interviews with expert faculty members from medical schools across the UK to ascertain MLM framework integration, teaching methods employed, evaluation methods and barriers to improvement. Findings Data were collected from 25 of the 33 UK medical schools (76 per cent response rate), with 23/25 reporting that MLM content is included in their curriculum. More medical schools assessed MLM competencies on admission than at any other time of the curriculum. Only 12 schools had evaluated MLM teaching at the time of data collection. The majority of medical schools reported barriers, including overfilled curricula and reluctance of staff to teach. Whilst 88 per cent of schools planned to increase MLM content over the next two years, there was a lack of consensus on proposed teaching content and methods. Research limitations/implications There is widespread inclusion of MLM in UK medical schools’ curricula, despite the existence of barriers. This study identified substantial heterogeneity in MLM teaching and assessment methods which does not meet students’ desired modes of delivery. Examples of national undergraduate MLM teaching exist worldwide, and lessons can be taken from these. Originality/value This is the first national evaluation of MLM in undergraduate medical school curricula in the UK, highlighting continuing challenges with executing MLM content despite numerous frameworks and international examples of successful execution