Alterações fisiológicas do sistema nervoso central de rã pelas toxinas de Cl. perfringens, Cl. oedematiens e Cl. septicum

The authors carried on experiences in order to confirm the neurotoxic theory of gas gangrene explained by Pacheco & Costa, uning preparations of isolated cord-posterior train of Leptodactylus ocellatus as described by OZORIO DE ALMEIDA & Cols. Frogs were intoxicated 3 days before the test with parcially purified toxins of Cl. perfringens, Cl. oedematiens and Cl. septicum. The intoxication produced a shortening of spinal reflexes duration time of such preparations, showing a typical alteration of the reflex activity of the spinal cord.

Periodic orbits near a heteroclinic loop formed by one dimensional orbit and a 2-dimensional manifold: application to the charged collinear 3-body problem

The paper is devoted to the study of a type of differential systems which appear usually in the study of some Hamiltonian systems with 2 degrees of freedom. We prove the existence of infinitely many periodic orbits on each negative energy level. All these periodic orbits pass near the total collision. Finally we apply these results to study the existence of periodic orbits in the charged collinear 3–body problem.

Free and fragmenting filling length

The filling length of an edge-circuit η in the Cayley 2-complex of a finite presentation of a group is the minimal integer length L such that there is a combinatorial null-homotopy of η down to a base point through loops of length at most L. We introduce similar notions in which the full-homotopy is not required to fix a base point, and in which the contracting loop is allowed to bifurcate. We exhibit a group in which the resulting filling invariants exhibit dramatically different behaviour to the standard notion of filling length. We also define the corresponding filling invariants for Riemannian manifolds and translate our results to this setting.

Ação inibidora do gás carbonico sobre as convulsões experimentais: III) experiências na crioepilepsia da rã: mecanismo da ação inibidora do gás carbonico nas convulsões

Neste trabalho descrevemos experiencias destinadas a mostrar a influência do pH nas crises convulsivas por resfriamento da medula espinhal da rã e estudar o mecanismo da ação inibidora do gás carbonico sobre estas conculsões. Verificamos que o CO² não age atravez um abaixamento do pH do sangue ou do meio intercelular. O gás carbonico teria uma ação específica que estaria ligada á sua grande difusibilidade. Essa sua propriedade permitiria que penetrasse ràpidamente no interior de neurônio, abaixando sensìvelmente o pH intracelular, sem que houvesse nítida variação do pH do sangue.

Endogeneizing know-how flows through the nature of R&D investments

In this paper we carefully link knowledge flows to and from a firms innovation process with this firms investment decisions. Three types of investments are considered: investments in applied research, investments in basic research, and investments in intellectual property protection. Only when basic research is performed, can the firm effectively access incoming knowledge flows and these incoming spillovers serve to increase the efficiency of own applied research.. The firm can at the same time influence outgoing knowledge flows, improving appropriability of its innovations, by investing in protection. Our results indicate that firms with small budgets for innovation will not invest in basic research. This occurs in the short run, when the budget for know-how creation is restricted, or in the long-run, when market opportunities are low, when legal protection is not very important, or, when the pool of accessible and relevant external know-how is limited. The ratio! of basic to applied research is non-decreasing in the size of the pool of accessible external know-how, the size and opportunity of the market, and, the effectiveness of intellectual property rights protection. This indicates the existence of economies of scale in basic research due to external market related factors. Empirical evidence from a sample of innovative manufacturing firms in Belgium confirms the economies of scale in basic research as a consequence of the firms capacity to access external knowledge flows and to protect intellectual property, as well as the complementarity between legal and strategic investments.

Generalized property R and the Schoenflies Conjecture

There is a relation between the generalized Property R Conjecture and the Schoenflies Conjecture that suggests a new line of attack on the latter. The new approach gives a quick proof of the genus 2 Schoenflies Conjecture and suffices to prove the genus 3 case, even in the absence of new progress on the generalized Property R Conjecture.

Firm strategies in R&D: cooperation and participation in R&D programs

This paper presents empirical evidence on firms’ decisions to cooperate in R&D and the extent to which government sponsored R&D programs increase cooperation. Using a sample of firms from the Spanish innovation survey we jointly estimate the determinants of firm participation in R&D programs and of choice of cooperation partners. We find that (i) firms participating in national and European programs have different profiles, suggesting program complementarity; (ii) private-private and publicprivate cooperation are associated on average with firms with different characteristics, and (iii) national R&D programs seem to have a positive effect on all types of cooperation, but especially on public-private partnerships.

Who participates in R&D subsidy programs? The case of spanish manufacturing firms.

Empirical evidence on the effectiveness of R&D subsidies to firms has produced mixed results so far. One possible explanation is that firms and project selection rules may be quite heterogeneous both across agencies and across industries, leading to different outcomes in terms of the induced additional private effort. Here we focus on the participation stage. Using a sample of Spanish firms, we test for differences across agencies and industries. Our results suggest that firms in the same industry face different hurdles to participate in different agencies’ programs, that participation patterns may reflect a combination of agency goals, and that patterns differ across high-tech and low-tech industries.

Contribuição ao estudo do gênero Phaenicia (R. D., 1863): (Diptera, Calliphoridae)

The author redescribes four species of Phaenicia refered to Brazil: P. sericata (Meigen), P. pallescens (Shannon), P. mexicana (Macquart) and P. eximia (Wiedemann). A new species, P. japuhybensis from the State of Rio de Janeiro, was also studied.