Das Holprinzip in der Pädiatrie und Neonatologie [The collecting principle in pediatrics and neonatology]

Quality medical care during transport of critically ill pediatric and neonatal patients is only possible if the referring hospital and the regional center cooperate closely. The experience of physicians and nurses involved is of great importance, and the choice of the transporting team should depend on the medical status of the patient and the skills of the physicians and nurses or paramedics. Critically ill children and neonates should be transported by specialized teams. Our statistics from the last 12 years show an increasing number of transports, with the majority of patients being referred from peripheral hospitals.

The Value of Imperfection : the Wabi-Sabi Principle in Aesthetics and Learning

OER-based learning has the potential to overcome many shortcomings and problems of traditional education. It is not hampered by IP restrictions; can depend on collaborative, cumulative, iterative refinement of resources; and the digital form provides unprecedented flexibility with respect to configuration and delivery. The OER community is a progressive group of educators and learners with decades of learning research to draw from, who know that we must prepare learners for an evolving and diverse reality. Despite this OER tends to replicate the unsuccessful characteristics of traditional education. To remedy this we may need to remember the importance of imperfection, mistakes, problems, disagreement, and the incomplete for engaged learning, and relinquish our notions of perfection, acknowledging that learners learn differently and we need diverse learners. We must stretch our perceptions of quality and provide mechanisms for engaging the incredible pool of educators globally to fulfill the promise of inclusive education.

Reversed shoulder arthroplasty baseplate fixed according to the major columns principle

Purpose Cadaveric study at our institution has demonstrated that optimal basaplate fixation of a reversed shoulder arthroplasty (RSA) could be achieved with screws in three major columns. Our aim was to review our early rate of aseptic glenoid loosening in a series of baseplate fixed according to this principle. Material and Methods Between 2005 and 2008, 48 RSA (Aequalis Reversed) were implanted in 48 patients with an average age of 74.4 years (range, 56 to 86 years). There were 37 women and 11 men. Twenty-seven primary RSAs were performed for cuff tear arthropathy, 3 after failed rotator cuff surgery, 6 for failed arthroplasties, 7 for acute fractures and 5 after failed ORIF. All baseplate fixation were done using a nonlocking posterior screw in the spine, a nonlocking anterior screw in the glenoid body, a locking superior screw in the coracoid and a locking inferior screw in the pillar. All patients were reviewed with standardized radiographs. The number of screws were reported. We measured the position of the screws in relation to the scapular spine and the coracoid process in two different views. We defined screw positions as totally, partially or out of the target. Finally we reported glenoid aseptic loosening which was defined as implant subsidence. Results Four patients were lost to follow-up. Thus, 44 shoulders could be reviewed after a mean follow-up of 13 months (range, 6 to 32 months). All baseplates were fixed with 4 screws. Thirty-seven (84%) screws were either partially or totally in the spine. Thus, 7 (16%) scapular spine screws were out of the target. No coracoid screw was out the target. Two (4.5%) patients had glenoid loosening. Both had a scapular spine and a coracoid screw partially in the bone. Conclusion Early aseptic glenoid loosening occurred before the two years follow-up and is most of time related to technical problems and/or insufficient bone stock and bone quality. Our study demonstrate that baseplate fixation according to the three columns principle is a reproducible technique and a valuable way to prevent early glenoid loosening.

Extremal principle of entropy production in the climate system

Paltridge found reasonable values for the most significant climatic variables through maximizing the material transport part of entropy production by using a simple box model. Here, we analyse Paltridge's box model to obtain the energy and the entropy balance equations separately. Derived expressions for global entropy production, which is a function of the radiation field, and even its material transport component, are shown to be different from those used by Paltridge. Plausible climatic states are found at extrema of these parameters. Feasible results are also obtained by minimizing the radiation part of entropy production, in agreement with one of Planck's results, Finally, globally averaged values of the entropy flux of radiation and material entropy production are obtained for two dynamical extreme cases: an earth with uniform temperature, and an earth in radiative equilibrium at each latitudinal point

Evolution: sociality as a driver of unorthodox reproduction.

An unusual reproductive system was discovered in desert ants, in which daughter queens are produced asexually via parthenogenesis, whereas workers develop from hybrid crosses between genetically divergent lineages. The system appears to be doomed to extinction.

Spatio-temporal differentiation and sociality in spiders.

Species that differ in their social system, and thus in traits such as group size and dispersal timing, may differ in their use of resources along spatial, temporal, or dietary dimensions. The role of sociality in creating differences in habitat use is best explored by studying closely related species or socially polymorphic species that differ in their social system, but share a common environment. Here we investigate whether five sympatric Anelosimus spider species that range from nearly solitary to highly social differ in their use of space and in their phenology as a function of their social system. By studying these species in Serra do Japi, Brazil, we find that the more social species, which form larger, longer-lived colonies, tend to live inside the forest, where sturdier, longer lasting vegetation is likely to offer better support for their nests. The less social species, which form single-family groups, in contrast, tend to occur on the forest edge where the vegetation is less robust. Within these two microhabitats, species with longer-lived colonies tend to occupy the potentially more stable positions closer to the core of the plants, while those with smaller and shorter-lived colonies build their nests towards the branch tips. The species further separate in their use of common habitat due to differences in the timing of their reproductive season. These patterns of habitat use suggest that the degree of sociality can enable otherwise similar species to differ from one another in ways that may facilitate their co-occurrence in a shared environment, a possibility that deserves further consideration.

Reversed shoulder arthroplasty baseplate fixed according to the three major columns principle

Introduction: Glenoid bone volume and bone quality can render the fixation of a reversed shoulder arthroplasty (RSA) basis plate hazardous. Cadaveric study at our institution has demonstrated that optimal baseplate fixation could be achieved with screws in three major columns. Our aim is to review our early rate of aseptic glenoid loosening in a series of baseplates fixed according to this principle. Methods: Between 2005 and 2008, 48 consecutive RSA (Reversed Aequalis) were implanted in 48 patients with an average age of 74.4 years (range, 56 to 86 years). There were 37 women and 11 men. Twenty-seven primary RSAs were performed for cuff tear arthropathy, 3 after failed rotator cuff surgery, 6 for failed arthroplasties, 7 for acute fractures and 5 after failed ORIF. All baseplate fixations were done using a nonlocking posterior screw in the scapular spine, a nonlocking anterior screw in the glenoid body, a locking superior screw in the coracoid and a locking inferior screw in the pillar. All patients were reviewed with standardized radiographs. We reported the positions of the screws in relation to the scapular spine and the coracoid process in two different views. We defined screw positions as totally, partially or out of the target. Finally, we reported aseptic glenoid loosening which was defined as implant subsidence. Results: Four patients were lost to follow-up. Thus 44 shoulders could be reviewed after a mean follow-up of 16 months (range, 9 to 32 months). Thirty-seven (84%) screws were either partially or totally in the spine. Thus, 7 (16%) scapular spine screws were out of the target. No coracoid screw was out of the target. At final follow-up control, we reported no glenoid loosening. Conclusion: Early glenoid loosening occurred before the two years follow-up and is most of time related to technical problems and/or insufficient glenoid bone stock and bone quality. Our study demonstrate that baseplate fixation of a RSA according to the three columns principle is a reproducible technique and a valuable way to prevent early glenoid loosening.

Firm-Specific Investment, Sticky Prices, and the Taylor Principle

According to the Taylor principle a central bank should adjust the nominal interest rate by more than one-for-one in response to changes in current inflation. Most of the existing literature supports the view that by following this simple recommendation a central bank can avoid being a source of unnecessary fluctuations in economic activity. The present paper shows that this conclusion is not robust with respect to the modelling of capital accumulation. We use our insights to discuss the desirability of alternative interest rate rules. Our results suggest a reinterpretation of monetary policy under Volcker and Greenspan: The empirically plausible characterization of monetary policy can explain the stabilization of macroeconomic outcomes observed in the early eighties for the US economy. The Taylor principle in itself cannot.

Co-evolution between sociality and dispersal: The role of synergistic cooperative benefits.

Explaining the evolution of sociality is challenging because social individuals face disadvantages that must be balanced by intrinsic benefits of living in a group. One potential route towards the evolution of sociality may emerge from the avoidance of dispersal, which can be risky in some environments. Although early studies found that local competition may cancel the benefits of cooperation in viscous populations, subsequent studies have identified conditions, such as the presence of kin recognition or specific demographic conditions, under which altruism will still spread. Most of these studies assume that the costs of cooperating outweigh the direct benefits (strong altruism). In nature, however, many organisms gain synergistic benefits from group living, which may counterbalance even costly altruistic behaviours. Here, we use an individual based model to investigate how dispersal and social behaviour co-evolve when social behaviours result in synergistic benefits that counterbalance the relative cost of altruism to a greater extent than assumed in previous models. When the cost of cooperation is high, selection for sociality responds strongly to the cost of dispersal. In particular, cooperation can begin to spread in a population when higher cooperation levels become correlated with lower dispersal tendencies within individuals. In contrast, less costly social behaviours are less sensitive to the cost of dispersal. In line with previous studies, we find that mechanisms of global population control also affect this relationship: when whole patches (groups) go extinct each generation, selection favours a relatively high dispersal propensity, and social behaviours evolve only when they are not very costly. If random individuals within groups experience mortality each generation to maintain a global carrying capacity, on the other hand, social behaviours spread and dispersal is reduced, even when the latter is not costly.

Hemoglobin enhances the biological activity of synthetic and natural bacterial (endotoxic) virulence factors: a general principle.

Although hemoglobin (Hb) is mainly present in the cytoplasm of erythrocytes (red blood cells), lower concentrations of pure, cell-free Hb are released permanently into the circulation due to an inherent intravascular hemolytic disruption of erythrocytes. Previously it was shown that the interaction of Hb with bacterial endotoxins (lipopolysaccharides, LPS) results in a significant increase of the biological activity of LPS. There is clear evidence that the enhancement of the biological activity of LPS by Hb is connected with a disaggregation of LPS. From these findings one questions whether the property to enhance the biological activity of endotoxin, in most cases proven by the ability to increase the cytokine (tumor-necrosis-factor-alpha, interleukins) production in human mononuclear cells, is restricted to bacterial endotoxin or is a more general principle in nature. To elucidate this question, we investigated the interaction of various synthetic and natural virulence (pathogenicity) factors with hemoglobin of human or sheep origin. In addition to enterobacterial R-type LPS a synthetic bacterial lipopeptide and synthetic phospholipid-like structures mimicking the lipid A portion of LPS were analysed. Furthermore, we also tested endotoxically inactive LPS and lipid A compounds such as those from Chlamydia trachomatis. We found that the observations made for endotoxically active form of LPS can be generalized for the other synthetic and natural virulence factors: In every case, the cytokine-production induced by them is increased by the addition of Hb. This biological property of Hb is connected with its physical property to convert the aggregate structures of the virulence factors into one with cubic symmetry, accompanied with a considerable reduction of the size and number of the original aggregates.

Firm-specific investment, sticky prices and the Taylor principle

According to the Taylor principle a central bank should adjust the nominal interest rate by more than one-for-one in response to changes in current inflation. Most of the existing literature supports the view that by following this simple recommendation a central bank can avoid being a source of unnecessary fluctuations in economic activity. The present paper shows that this conclusion is not robust with respect to the modelling of capital accumulation. We use our insights to discuss the desirability of alternative interest raterules. Our results suggest a reinterpretation of monetary policy under Volcker and Greenspan: The empirically plausible characterization of monetary policy can explain the stabilization of macroeconomic outcomes observed in the early eighties for the US economy. The Taylor principle in itself cannot.

On the receiver pays principle

This paper extends the theory of network competition betweentelecommunications operators by allowing receivers to derive a surplusfrom receiving calls (call externality) and to affect the volume ofcommunications by hanging up (receiver sovereignty). We investigate theextent to which receiver charges can lead to an internalization of thecalling externality. When the receiver charge and the termination(access) charge are both regulated, there exists an e±cient equilibrium.Effciency requires a termination discount. When reception charges aremarket determined, it is optimal for each operator to set the prices foremission and reception at their off-net costs. For an appropriately chosentermination charge, the symmetric equilibrium is again effcient. Lastly,we show that network-based price discrimination creates strong incentivesfor connectivity breakdowns, even between equal networks.

The second law of thermodynamics and the global climate system : A review of the maximum entropy production principle

The long-term mean properties of the global climate system and those of turbulent fluid systems are reviewed from a thermodynamic viewpoint. Two general expressions are derived for a rate of entropy production due to thermal and viscous dissipation (turbulent dissipation) in a fluid system. It is shown with these expressions that maximum entropy production in the Earth s climate system suggested by Paltridge, as well as maximum transport properties of heat or momentum in a turbulent system suggested by Malkus and Busse, correspond to a state in which the rate of entropy production due to the turbulent dissipation is at a maximum. Entropy production due to absorption of solar radiation in the climate system is found to be irrelevant to the maximized properties associated with turbulence. The hypothesis of maximum entropy production also seems to be applicable to the planetary atmospheres of Mars and Titan and perhaps to mantle convection. Lorenz s conjecture on maximum generation of available potential energy is shown to be akin to this hypothesis with a few minor approximations. A possible mechanism by which turbulent fluid systems adjust themselves to the states of maximum entropy production is presented as a selffeedback mechanism for the generation of available potential energy. These results tend to support the hypothesis of maximum entropy production that underlies a wide variety of nonlinear fluid systems, including our planet as well as other planets and stars