Gradualism and Irreversibility.

This paper considers a class of two-player dynamic games in which each player controls a one-dimensional variable which we interpret as a level of cooperation. In the base model, there is an irreversibility constraint stating that this variable can never be reduced, only increased. It otherwise satisfies the usual discounted repeated game assumptions.GAMES ; PUBLIC GOODS ; COOPERATION

The 22-Year Hale Cycle in Cosmic Ray Flux – Evidence for Direct Heliospheric Modulation

Abstract The ability to predict times of greater galactic cosmic ray (GCR) fluxes is important for reducing the hazards caused by these particles to satellite communications, aviation, or astronauts. The 11-year solar-cycle variation in cosmic rays is highly correlated with the strength of the heliospheric magnetic field. Differences in GCR flux during alternate solar cycles yield a 22-year cycle, known as the Hale Cycle, which is thought to be due to different particle drift patterns when the northern solar pole has predominantly positive (denoted as qA>0 cycle) or negative (qA0 cycles than for qA0 and more sharply peaked for qA0 solar cycles, when the difference in GCR flux is most apparent. This suggests that particle drifts may not be the sole mechanism responsible for the Hale Cycle in GCR flux at Earth. However, we also demonstrate that these polarity-dependent heliospheric differences are evident during the space-age but are much less clear in earlier data: using geomagnetic reconstructions, we show that for the period of 1905 – 1965, alternate polarities do not give as significant a difference during the declining phase of the solar cycle. Thus we suggest that the 22-year cycle in cosmic-ray flux is at least partly the result of direct modulation by the heliospheric magnetic field and that this effect may be primarily limited to the grand solar maximum of the space-age

Una primera aproximació a la riquesa específica dels odonats al Parc Natural de la Zona Volcànica de la Garrotxa

Es van detectar 35 espècies d'odonats al Parc Natural de la Zona Volcànica de la Garrotxa (NE península Ibèrica; PNZVG) entre el 2002 i el 2003, dels quals 27 van ser observades als estanys de Can Jordà. Intentem explicar tanta riquesa específica mitjançant una anàlisi de tres factors. Primer, el PNZVG es troba en una cruïlla de dues regions biogeogràfiques, cosa que confereix molta diversitat al Parc Natural i a la comunitat d'odonats que hi viu. Segon, els voltants dels ambients aquàtics del PNZVG són diversos i hi ha una barreja d'hàbitats a prop que satisfà les preferències ecològiques d'un bon grapat d'espècies. Tercer, hi ha una diversitat notable de classes d'hàbitats aquàtics al PNZVG, alguns amb la qualitat de l'aigua molt alta. Es comenta al final que cal entendre el perquè de tanta riquesa específica per tal d'incidir en la gestió i creació d'hàbitat per als odonats al PNZVG i a altres espais protegits.A total of 35 species of odonata (dragonflies and damselflies) were recorded from the Natural Park of the Volcanic Zone of La Garrotxa (NE Iberian Peninsula; PNZVG) in 2002 and 2003, of which 27 were observed at Els Estanys de Can Jordà. Three factors were considered in explaining this species-richness. First, the PNZVG is located at a confluence of biogeographical regions, a fact which ensures that there is great variety in the habitat type in the natural park and therefore in the odonata that fly there. Secondly, the habitat surrounding the wetlands in the natural park is very varied and satisfies the ecological needs of a great variety of species. Lastly, the wetlands themselves in the PNVZG are very varied, and have good water quality. At the end we comment that only by understanding the reasons for such great species-richness can habitat be managed for odonata in the PNVZG and elsewhere.Se detectaron 35 especies de odonata en el Parque Natural de la Zona Volcánica de La Garrotxa (NE península Ibérica; PNZVG) entre 2002 y 2003, de las cuales 27 se observaron en la zona de los estanques de Can Jordà. Este artículo intenta explicar tanta riqueza específica mediante un análisis de tres factores. Primero, el PNZVG se encuentra en un cruce de dos regiones biogeográficas, lo cual implica mucha diversidad natural. Segundo, los entornos de los ambientes acuáticos del PNZVG son diversos y hay una buena representación de diferentes hábitats que satisfacen las preferencias ecológicas de muchas especies. Tercero, dentro de los tipos de hábitat acuático en el parque, hay también una buena diversidad, algunas con una calidad de agua muy alta. Se comenta al final que hay que estudiar esta riqueza específica para influir más en la gestión y la creación de hábitat para los odonata en el parque y otros espacios protegidos

Gradualism and irreversibility

This paper considers a class of two-player dynamic games in which each player controls a one-dimensional variable which we interpret as a level of cooperation. In the base model, there is an irreversibility constraint stating that this variable can never be reduced, only increased. It otherwise satisfies the usual discounted repeated game assumptions. Under certain restrictions on the payoff function, which make the stage game resemble a continuous version of the Prisoners’ Dilemma, we characterize efficient symmetric equilibria, and show that cooperation levels exhibit gradualism and converge, when payoffs are smooth, to a level strictly below the one-shot efficient level: the irreversibility induces a steady-state as well as a dynamic inefficiency. As players become very patient, however, payoffs converge to (though never attain) the efficient level. We also show that a related model in which an irreversibility arises through players choosing an incremental variable, such as investment, can be transformed into the base model with similar results. Applications to a public goods sequential contribution model and a model of capacity reduction in a declining industry are discussed. The analysis is extended to incorporate partial reversibility, asymmetric equilibria, and sequential moves

The handbook of design management

The management of design has emerged as central to the operational and strategic options of any successful organization. The Handbook of Design Management presents a state of the art overview of the subject - its methodologies, current debates, history and future. The Handbook covers the breadth of principles, methods and practices that shape design management across the different design disciplines. These theories and practices reach from the operational to the strategic, from the product to the organization. Bringing together leading international scholars, the Handbook provides a guide to the latest research in the field. It also documents the shifts that have been taking place both in management and in design which have highlighted the value of design thinking and design education to organizations. Presenting the first systematic overview of the subject - and offering a wide range of examples, insights and analysis - the Handbook is an invaluable resource for researchers and students in design and management as well as for design practitioners and professional managers

Solar cycle 24: what is the sun up to?

March 2012 brought the first solar and geomagnetic disturbances of any note during solar cycle 24. But perhaps what was most remarkable about these events was how unremarkable they were compared to others during the space-age, attracting attention only because solar activity had been so quiet. This follows an exceptionally low and long-lived solar cycle minimum, and so the current cycle looks likely to extend a long-term decline in solar activity that started around 1985 and that could even lead to conditions similar to the Maunder minimum within 40 years from now, with implications for solar-terrestrial science and the mitigation of space weather hazards and maybe even for climate in certain regions and seasons

Decadal trends in the diurnal variation of galactic cosmic rays observed using neutron monitor data

The diurnal variation (DV) in galactic cosmic ray (GCR) flux is a widely observed phenomenon in neutron monitor data. The background variation considered primarily in this study is due to the balance between the convection of energetic particles away from the Sun and the inward diffusion of energetic particles along magnetic field lines. However, there are also times of enhanced DV following geomagnetic disturbances caused by coronal mass ejections or corotating interaction regions. In this study we investigate changes in the DV over four solar cycles using ground-based neutron monitors at different magnetic latitudes and longitudes at Earth. We divide all of the hourly neutron monitor data into magnetic polarity cycles to investigate cycle-to-cycle variations in the phase and amplitude of the DV. The results show, in general, a similarity between each of the A  0 cycles, but with a phase change between the two. To investigate this further, we split the neutron monitor data by solar magnetic polarity between times when the dominant polarity was either directed outward (positive) or inward (negative) at the northern solar pole. We find that the maxima and minima of the DV changes by, typically, 1–2 h between the two polarity states for all non-polar neutron monitors. This difference between cycles becomes even larger in amplitude and phase with the removal of periods with enhanced DV caused by solar wind transients. The time difference between polarity cycles is found to vary in a 22-year cycle for both the maximum and minimum times of the DV. The times of the maximum and minimum in the DV do not always vary in the same manner between A > 0 and A  0 cycles. In most cases the change in timing of the maximum /minimum is greatest with the stations' geomagnetic cut-off rigidity shows little variation in the DV phase with latitude. We conclude that the change in the DV with the dominant solar polar polarity is not as simple as a phase change, but rather an asymmetric variation which is sensitive to the neutron monitor's asymptotic viewing direction

Galactic cosmic rays in the heliosphere

Simon R Thomas, Mathew J Owens and Mike Lockwood discuss how neutron monitor counts can help map space weather. This won the 2014 Rishbeth Prize for the best student talk at the Hot Spring MIST Meeting in Bath, April 2014