Testicular endocrine activity is upregulated by D-Aspartic acid in the green frog Rana esculenta

This study investigated the involvement of D-aspartic acid (D-Asp) in testicular steroidogenesis of the green frog Rana esculenta and its effect on stimulation of thumb pad morphology and glandular activity, a typical testosterone-dependent secondary sexual characteristic in this amphibian species. In the testis, D-Asp concentrations vary significantly during the reproductive cycle: they are low in pre- and post-reproductive periods, but reach peak levels in the reproductive period (140-236 nmol/g wet tissue). Moreover, the concentrations of D-Asp in the testis through the sexual cycle positively match the testosterone levels in the gonad and the plasma. The racemase activity evaluated during the cycle expresses its peak when D-Asp and testosterone levels are highest, that is, during the reproductive period, confirming the synthesis of D-Asp from L-Asp by an aspartate racemase. Short-term in vivo experiments consisting of a single injection of D-Asp (2.0 micro mol/g body weight) demonstrated that this amino acid accumulates significantly in the testis, and after 3 h its uptake is coupled with a testosterone increase in both testis and plasma. Moreover, within 18 h of amino acid administration, the D-Asp concentration in the testis decreased along with the testosterone titer to prestimulation levels. Other amino acids (L-Asp, D-Glu and L-Glu) used instead of D-Asp were ineffective, confirming that the significant increase in testicular testosterone was a specific feature of this amino acid. In long-term experiments, D-Asp had been administered chronically to frogs caught during the three phases of the reproductive cycle, inducing testosterone increase and 17beta-estradiol decrease in the gonad during the pre- and post-reproductive period, and vice versa during the reproductive period

Parametric study of the load-bearing mechanisms in RC beam-grids to resist progressive collapse

Recently, several structural failures demonstrated the disastrous consequences of progressive collapse and raised the awareness of the engineering community. However the low probability of progressive collapse makes it uneconomical to design every building against progressive collapse using conventional design methods. Furthermore in most cases the initiating events of progressive collapses are unknown during the design. As such, consideration of secondary load-carrying mechanisms can be an effective alternative. These mechanisms include compressive arch action (CAA) and tensile catenary action (TCA) in reinforced concrete (RC) beams. Several researchers have investigated the effects of CAA and TCA experimentally and numerically in individual RC beams. However to date limited studies have been carried out to study these mechanisms in RC beam-grids. Hence in this contribution a validated numerical model is developed to study and quantify the individual contributions and development of the different mechanisms in RC beam-grids. Parametric studies are performed in relation to the influence of the aspect ratio of the grid, reinforcement ratio and ultimate reinforcement strain

Transparenz und Evaluierbarkeit des erziehungswissenschaftlichen Publikationsaufkommens. Eine anwendungsorientierte Studie

Der Beitrag stellt Ziele und erste Ergebnisse des DFG-Projekts "Innovative bibliometrische Verfahren zur kontinuierlichen Beobachtung der sozialwissenschaftlichen Forschungsproduktion" vor. Eine Analyse des Publikationsverhaltens von Erziehungswissenschaftlern zeigt die große Bedeutung des Publikationstyps Sammelwerksbeitrag und der Publikationssprache Deutsch, aber auch eine ausgeprägte Heterogenität in der Publikationspraxis von erziehungswissenschaftlichen Institutionen. Skizziert wird schließlich der Vorschlag für einen neuen, dieser Publikationspraxis angemessenen, bibliometrischen Indikator. (DIPF/Autor

Railway traffic disturbance management by means of control strategies applied to operations in the transit system

Railway systems in metropolitan areas support a high density of daily traffic that is exposed to different types of disturbances in the service. An interesting topic in the literature is to obtain action protocols in the presence of contingencies which can affect the system operation, avoiding the propagation of perturbation and minimizing its negative consequences. Assume that, with a small margin of time (e.g. one day), the decision-maker of the transportation network is knowing that a part of the train fleet will become inoperative temporarily along a specific transit line and none additional vehicle will be able to restore the affected services. The decision to be taken in consequence will require to reschedule the existing services by possibly reducing the number of expeditions (line runs). This will affect travellers who regularly use the transit system to get around. Consider that the decision-maker aims to lose the least number of passengers as a consequence of having introduced changes into the transit line. A strategy that could be applied in this context is to remove those line runs which are historically less used by travellers without affecting the remaining services. Another alternative strategy might be to reschedule the timetables of the available units, taking into account the pattern of arrivals of users to the boarding stations and the user behavior during waiting times (announced in situ). The aim of this work consists of assessing the strategy of train rescheduling along the current transportation line when the supply must be reduced in order to reinforce the service of another line, exploited by the same public operator, which has suffered an incidence or emergency.Ministerio de Economía y CompetitividadFondo Europeo de Desarrollo Regiona

Réduction de la luxation de la tête radiale dans le cadre de la maladie exostosante: à propos d’un cas

La luxation de la tête radiale dans le cadre de la maladie exostosante  constitue une complication de déséquilibre de croissance des deux os del'avant bras secondaire à une exostose distale de l'ulna. Le traitement est difficile et controversé par les auteurs. Nous présentons une technique originale pour le traitement de cette entité. Après la correction de l'index radio-cubital inférieur par un allongement progressif de l'ulna, une fixation radio-cubitale inférieure par les fiches distales de l'Orthofix® et un deuxième allongement de l'ulna permet l'abaissement de la tête radiale et sa réduction. La réduction progressive par allongement de l'ulna par la méthode de callotasis constitue une technique séduisante et réalise l'inverse du ce qui passé lors de ralentissement de croissance de l'ulna sous l'effet de l'exostose ulnaire

La nuova industria del costruire

Nel mondo delle costruzioni odierno diventa sempre più difficile rinunciare a quei vantaggi qualitativi e quantitativi che solo un’industrializzazione edilizia avanzata può offrire. Mentre nei campi delle costruzioni commerciali ed industriali questo concetto è già affermato con successo sul mercato, nel campo degli edifici residenziali, tipicamente caratterizzato da una più complessa interazione tra architettura, struttura ed impiantistica, la metodologia tradizionale di costruzione è ancora legata a metodi semiartigianali. L’articolo mostra una soluzione completa per interventi di urbanizzazione complessa caratterizzata da un elevato tasso di industrializzazione. L’ottimizzazione ingegneristica dei componenti e l’innovazione tecnologica delle metodologie di progettazione e di produzione conferiscono ai prodotti edilizi robustezza, velocità di realizzazione ed alta competitività