Diversity improves performance in excitable networks

As few real systems comprise indistinguishable units, diversity is a hallmark of nature. Diversity among interacting units shapes properties of collective behavior such as synchronization and information transmission. However, the benefits of diversity on information processing at the edge of a phase transition, ordinarily assumed to emerge from identical elements, remain largely unexplored. Analyzing a general model of excitable systems with heterogeneous excitability, we find that diversity can greatly enhance optimal performance (by two orders of magnitude) when distinguishing incoming inputs. Heterogeneous systems possess a subset of specialized elements whose capability greatly exceeds that of the nonspecialized elements. Nonetheless, the behavior of the whole network can outperform all subgroups. We also find that diversity can yield multiple percolation, with performance optimized at tricriticality. Our results are robust in specific and more realistic neuronal systems comprising a combination of excitatory and inhibitory units, and indicate that diversity-induced amplification can be harnessed by neuronal systems for evaluating stimulus intensities.Comment: 17 pages, 7 figure

ASAP: An Automatic Algorithm Selection Approach for Planning

Despite the advances made in the last decade in automated planning, no planner out- performs all the others in every known benchmark domain. This observation motivates the idea of selecting different planning algorithms for different domains. Moreover, the planners’ performances are affected by the structure of the search space, which depends on the encoding of the considered domain. In many domains, the performance of a plan- ner can be improved by exploiting additional knowledge, for instance, in the form of macro-operators or entanglements. In this paper we propose ASAP, an automatic Algorithm Selection Approach for Planning that: (i) for a given domain initially learns additional knowledge, in the form of macro-operators and entanglements, which is used for creating different encodings of the given planning domain and problems, and (ii) explores the 2 dimensional space of available algorithms, defined as encodings–planners couples, and then (iii) selects the most promising algorithm for optimising either the runtimes or the quality of the solution plans

Flavored tetraquark spectroscopy

The recent confirmation of the charged charmonium like resonance Z(4430) by the LHCb experiment strongly suggests the existence of QCD multi quark bound states. Some preliminary results about hypothetical flavored tetraquark mesons are reported. Such states are particularly amenable to Lattice QCD studies as their interpolating operators do not overlap with those of ordinary hidden-charm mesons

Coverage of exposed hardware after lower leg fractures with free flaps or pedicled flaps

Abstract. – OBJECTIVE: The placement of osteosynthetic materials in the leg may be complicated by hardware exposure. Successful soft tissue reconstruction often provides a critical means for limb salvage in patients with hardware exposure in the leg. Free flaps are currently considered the standard surgical procedure for soft tissue coverage of the wounds with internal hardware exposure. However, to date, no conclusive literature shows the superiority of a specific type of flap. MATERIALS AND METHODS: The current review compares data from the literature concerning outcomes and complications of free and pedicled flaps for exposed osteosynthetic material preservation in the leg. RESULTS: A total of 81 cases from twelve different articles presenting internal hardware exposure of the leg were analyzed in our study. Thirty-two patients underwent immediate reconstructive surgery with pedicled flaps, while forty-nine patients underwent free flap reconstruction. The overall survival rate for pedicled flaps was 96.77%, while for free flaps it was 97.77%. The overall implant preservation rate was 78.12% for pedicled flaps and 53.33% for free flaps. With reference to postoperative complications, the overall complication rate was 46.87% for pedicled flaps and 10.20% for free flaps. CONCLUSIONS: No significant difference was found in terms of overall flap survival. However, a significant difference was found regarding successful implant preservation (78.12% in the pedicled flap group vs. 53.33% in the free flap group). In particular, the first observation appears to be in contrast with the current trend of considering the free flaps the first choice procedure for soft tissue coverage of the wounds with internal hardware exposure. Nevertheless, a higher occurrence of postoperative complications was observed in the pedicled flap group (46.87% vs. 10.20%). The choice of the most appropriate reconstructive procedure should take into account several issues including the size of the wounds with internal hardware exposure, the possibility of soft tissue coverage with pedicled flaps, the availability of recipient vessels, general conditions of the patients (such as age, diabetes, smoking history), patients’ preference and presence of a microsurgical team. However, according to the results of this review, we believe that pedicled flap reconstruction should be reconsidered as a valid alternative procedure for skin tissue loss with hardware exposure whenever it is possible

The importance for growth of dietary intake of calcium and vitamin D

OBJECTIVE: To investigate the role of dietary calcium and vitamin D in the process of growth and development of children and adolescents, focusing in particular on the prevention and treatment of delayed growth caused by nutritional deficiency. SOURCES: Information was gathered from articles published in the last 2 decades, from searches on the databases SciELO, PubMed and Medline, technical books and publications of international organizations. SUMMARY OF THE FINDINGS: Growth is influenced by intrinsic (genetic and metabolic) and extrinsic factors (environmental factors such as diet, health, hygiene, housing and access to health services). Among the nutritional factors are vitamin and oligoelement deficiencies which may be associated with malnutrition or caused by insufficient absorption. Since calcium is one of the main mineral components of bone tissue, it is essential for adequate bone formation and, considering that vitamin D plays an important role in calcium metabolism, a diet with insufficient quantities of these nutrients can impact on the formation of the skeleton and on the process of growth and development. CONCLUSIONS: In children and adolescents, low intake or low absorption of calcium and vitamin D may limit their statural growth, and it is necessary to supply sufficient quantities of both during the critical growth phases.OBJETIVO: Verificar o papel nutricional do cálcio e da vitamina D no processo de crescimento e desenvolvimento infanto-juvenil, visando, em especial, a prevenção e o tratamento do atraso de crescimento causado por deficiência nutricional. FONTES DOS DADOS: As informações foram coletadas a partir de artigos publicados nas 2 últimas décadas, pesquisados nas bases de dados SciELO, PubMed e MEDLINE, livros técnicos e publicações de organizações internacionais. SÍNTESE DOS DADOS: O crescimento sofre influência de fatores intrínsecos (genéticos e metabólicos) e extrínsecos (fatores ambientais, como alimentação, saúde, higiene, habitação, e o acesso aos serviços de saúde). Entre os fatores nutricionais, destacam-se as deficiências de vitaminas e oligoelementos que podem se associar à desnutrição ou depender da absorção insuficiente dos mesmos. Sendo o cálcio um dos principais componentes do tecido mineral ósseo, este é essencial para uma adequada formação óssea e, considerando que a vitamina D desempenha papel importante no metabolismo do cálcio, uma dieta insuficiente nesses nutrientes pode influenciar a formação do esqueleto e o processo de crescimento e desenvolvimento. CONCLUSÕES: A baixa ingestão ou baixa absorção de cálcio e vitamina D em crianças e adolescentes pode limitar seu desenvolvimento estatural, sendo necessário fornecer quantidades suficientes de ambos na fase crítica do crescimento.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)HCPA Fundo de Incentivo a Pesquisa e Eventos (FIPE)Centro de Endocrinologia e Diabetes do Rio Grande do Sul (CEDERS)Universidade Federal do Rio Grande do SulUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUFRGS Faculdade de Medicina Programa de Pós-Graduação em Ciências Médicas: Endocrinologia e NutriçãoUNIFESP, EPMSciEL

Extremal covariant measurements

We characterize the extremal points of the convex set of quantum measurements that are covariant under a finite-dimensional projective representation of a compact group, with action of the group on the measurement probability space which is generally non-transitive. In this case the POVM density is made of multiple orbits of positive operators, and, in the case of extremal measurements, we provide a bound for the number of orbits and for the rank of POVM elements. Two relevant applications are considered, concerning state discrimination with mutually unbiased bases and the maximization of the mutual information.Comment: 11 pages, no figure

How continuous quantum measurements in finite dimension are actually discrete

We show that in finite dimension a quantum measurement with continuous set of outcomes is always equivalent to a continuous random choice of measurements with only finite outcomes.Comment: 4 pages, 1 figur