WorldWideScience

Sample records for trends regime shifts

  1. Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

    Science.gov (United States)

    Flint, Paul L.

    2013-01-01

    Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.

  2. Integrated trend assessment of ecosystem changes in the Limfjord (Denmark): evidence of a recent regime shift?

    DEFF Research Database (Denmark)

    Tomczak, Maciej Tomasz; Dinesen, Grete E.; Hoffmann, Erik

    2012-01-01

    An integrated ecosystem assessment was carried out for the Limfjord over the period from 1984 to 2008 to describe changes in ecosystem structure and potentially important drivers. The Limfjord is an eutrophic transitional Danish fjord system with the main inflow from the North Sea in the west and...... further showed the regime shift to be driven by a combination of anthropogenic pressures and possible interplay with climatic disturbance......An integrated ecosystem assessment was carried out for the Limfjord over the period from 1984 to 2008 to describe changes in ecosystem structure and potentially important drivers. The Limfjord is an eutrophic transitional Danish fjord system with the main inflow from the North Sea in the west......), jellyfish, common shore crab, starfish and blue mussels. We interpret this change as a regime shift that showed a similar temporal pattern to regime shifts identified in adjacent seas. The observed changes in trophic interactions and food web reorganisation suggested a non-linear regime shift. The analyses...

  3. Integrated ecological and chemical food web accumulation modeling explains PAH temporal trends during regime shifts in a shallow lake.

    Science.gov (United States)

    Kong, Xiangzhen; He, Wei; Qin, Ning; Liu, Wenxiu; Yang, Bin; Yang, Chen; Xu, Fuliu; Mooij, Wolf M; Koelmans, Albert A

    2017-08-01

    Shallow lakes can switch suddenly from a turbid situation with high concentrations of phytoplankton and other suspended solids to a vegetated state with clear water, and vice versa. These alternative stable states may have a substantial impact on the fate of hydrophobic organic compounds (HOCs). Models that are fit to simulate impacts from these complex interactions are scarce. We developed a contaminant fate model which is linked to an ecosystem model (PCLake) for shallow lakes. This integrated model was successful in simulating long-term dynamics (1953-2012) of representative polycyclic aromatic hydrocarbons (PAHs) in the main biotic and abiotic components in a large shallow lake (Chaohu in China), which has undergone regime shifts in this period. Historical records from sediment cores were used to evaluate the model. The model revealed that regime shifts in shallow lakes had a strong impact on the fate of less hydrophobic compounds due to the large storage capacity of macrophytes, which accumulated up to 55.6% of phenanthrene in the clear state. The abrupt disappearance of macrophytes after the regime shift resulted in a sudden change in phenanthrene distribution, as the sediment became the major sink. For more hydrophobic compounds such as benzo(a)pyrene, the modeled impact of the regime shift was negligible for the whole environment, yet large for biotic compartments. This study is the first to provide a full mechanistic analysis of the impact of regime shifts on the fate of PAHs in a real lake ecosystem. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Stochastic dynamical models for ecological regime shifts

    DEFF Research Database (Denmark)

    Møller, Jan Kloppenborg; Carstensen, Jacob; Madsen, Henrik

    the physical and biological knowledge of the system, and nonlinearities introduced here can generate regime shifts or enhance the probability of regime shifts in the case of stochastic models, typically characterized by a threshold value for the known driver. A simple model for light competition between...... definition and stability of regimes become less subtle. Ecological regime shifts and their modeling must be viewed in a probabilistic manner, particularly if such model results are to be used in ecosystem management....

  5. Multiscale regime shifts and planetary boundaries

    NARCIS (Netherlands)

    Hughes, T.P.; Carpenter, S.; Rockstrom, J.; Scheffer, M.; Walker, B.

    2013-01-01

    Life on Earth has repeatedly displayed abrupt and massive changes in the past, and there is no reason to expect that comparable planetary-scale regime shifts will not continue in the future. Different lines of evidence indicate that regime shifts occur when the climate or biosphere transgresses a

  6. Ecosystem regime shifts disrupt trophic structure.

    Science.gov (United States)

    Hempson, Tessa N; Graham, Nicholas A J; MacNeil, M Aaron; Hoey, Andrew S; Wilson, Shaun K

    2018-01-01

    Regime shifts between alternative stable ecosystem states are becoming commonplace due to the combined effects of local stressors and global climate change. Alternative states are characterized as substantially different in form and function from pre-disturbance states, disrupting the delivery of ecosystem services and functions. On coral reefs, regime shifts are typically characterized by a change in the benthic composition from coral to macroalgal dominance. Such fundamental shifts in the benthos are anticipated to impact associated fish communities that are reliant on the reef for food and shelter, yet there is limited understanding of how regime shifts propagate through the fish community over time, relative to initial or recovery conditions. This study addresses this knowledge gap using long-term data of coral reef regime shifts and recovery on Seychelles reefs following the 1998 mass bleaching event. It shows how trophic structure of the reef fish community becomes increasingly dissimilar between alternative reef ecosystem states (regime-shifted vs. recovering) with time since disturbance. Regime-shifted reefs developed a concave trophic structure, with increased biomass in base trophic levels as herbivorous species benefitted from increased algal resources. Mid trophic level species, including specialists such as corallivores, declined with loss of coral habitat, while biomass was retained in upper trophic levels by large-bodied, generalist invertivores. Recovering reefs also experienced an initial decline in mid trophic level biomass, but moved toward a bottom-heavy pyramid shape, with a wide range of feeding groups (e.g., planktivores, corallivores, omnivores) represented at mid trophic levels. Given the importance of coral reef fishes in maintaining the ecological function of coral reef ecosystems and their associated fisheries, understanding the effects of regime shifts on these communities is essential to inform decisions that enhance ecological

  7. Early detection of ecosystem regime shifts

    DEFF Research Database (Denmark)

    Lindegren, Martin; Dakos, Vasilis; Groeger, Joachim P.

    2012-01-01

    methods may have limited utility in ecosystem-based management as they show no or weak potential for early-warning. We therefore propose a multiple method approach for early detection of ecosystem regime shifts in monitoring data that may be useful in informing timely management actions in the face...

  8. Regime Shifts and Resilience in Fisheries Management

    NARCIS (Netherlands)

    Li, Chuan Zhong; Villasante, Sebastian; Zhu, Xueqin

    2016-01-01

    We investigate the role of potential regime shifts in Argentinean hake fishery and the inter-linkage between ecological and economic resilience. We develop a theoretical model incorporated with the hazard function for resource management under alternative conditions, and derive the corrective

  9. Regime shift of snow days in Switzerland

    Science.gov (United States)

    Marty, Christoph

    2008-06-01

    The number of days with a snow depth above a certain threshold is the key factor for winter tourism in an Alpine country like Switzerland. An investigation of 34 long-term stations between 200 and 1800 m asl (above sea level) going back for at least the last 60 years (1948-2007) shows an unprecedented series of low snow winters in the last 20 years. The signal is uniform despite high regional differences. A shift detection analysis revealed a significant step-like decrease in snow days at the end of the 1980's with no clear trend since then. This abrupt change resulted in a loss of 20% to 60% of the total snow days. The stepwise increase of the mean winter temperature at the end of the 1980's and its close correlation with the snow day anomalies corroborate the sensitivity of the mid-latitude winter to the climate change induced temperature increase.

  10. Global regime shift dynamics of catastrophic sea urchin overgrazing

    Science.gov (United States)

    Ling, S. D.; Scheibling, R. E.; Rassweiler, A.; Johnson, C. R.; Shears, N.; Connell, S. D.; Salomon, A. K.; Norderhaug, K. M.; Pérez-Matus, A.; Hernández, J. C.; Clemente, S.; Blamey, L. K.; Hereu, B.; Ballesteros, E.; Sala, E.; Garrabou, J.; Cebrian, E.; Zabala, M.; Fujita, D.; Johnson, L. E.

    2015-01-01

    A pronounced, widespread and persistent regime shift among marine ecosystems is observable on temperate rocky reefs as a result of sea urchin overgrazing. Here, we empirically define regime-shift dynamics for this grazing system which transitions between productive macroalgal beds and impoverished urchin barrens. Catastrophic in nature, urchin overgrazing in a well-studied Australian system demonstrates a discontinuous regime shift, which is of particular management concern as recovery of desirable macroalgal beds requires reducing grazers to well below the initial threshold of overgrazing. Generality of this regime-shift dynamic is explored across 13 rocky reef systems (spanning 11 different regions from both hemispheres) by compiling available survey data (totalling 10 901 quadrats surveyed in situ) plus experimental regime-shift responses (observed during a total of 57 in situ manipulations). The emergent and globally coherent pattern shows urchin grazing to cause a discontinuous ‘catastrophic’ regime shift, with hysteresis effect of approximately one order of magnitude in urchin biomass between critical thresholds of overgrazing and recovery. Different life-history traits appear to create asymmetry in the pace of overgrazing versus recovery. Once shifted, strong feedback mechanisms provide resilience for each alternative state thus defining the catastrophic nature of this regime shift. Importantly, human-derived stressors can act to erode resilience of desirable macroalgal beds while strengthening resilience of urchin barrens, thus exacerbating the risk, spatial extent and irreversibility of an unwanted regime shift for marine ecosystems.

  11. Regime shifts and resilience in China's coastal ecosystems.

    Science.gov (United States)

    Zhang, Ke

    2016-02-01

    Regime shift often results in large, abrupt, and persistent changes in the provision of ecosystem services and can therefore have significant impacts on human wellbeing. Understanding regime shifts has profound implications for ecosystem recovery and management. China's coastal ecosystems have experienced substantial deterioration within the past decades, at a scale and speed the world has never seen before. Yet, information about this coastal ecosystem change from a dynamics perspective is quite limited. In this review, I synthesize existing information on coastal ecosystem regime shifts in China and discuss their interactions and cascading effects. The accumulation of regime shifts in China's coastal ecosystems suggests that the desired system resilience has been profoundly eroded, increasing the potential of abrupt shifts to undesirable states at a larger scale, especially given multiple escalating pressures. Policy and management strategies need to incorporate resilience approaches in order to cope with future challenges and avoid major losses in China's coastal ecosystem services.

  12. Regime shifts, resilience and recovery of a cod stock

    DEFF Research Database (Denmark)

    Lindegren, Martin; Diekmann, Rabea; Möllmann, Christian

    2010-01-01

    In the North and Baltic seas Atlantic cod Gadus morhua stocks collapsed as part or one of the major factors inducing large-scale ecosystem regime shifts. Determining the relative contribution of overfishing and climate variability in causing these shifts has proven difficult. While facing similar...

  13. Beta Risk and Regime Shift in Market Volatility

    OpenAIRE

    Don U.A. Galagedera; Roland G. Shami

    2004-01-01

    In this paper, we relate security returns in the thirty securities in the Dow Jones index to regime shifts in the market portfolio (S&P500) volatility. We model market volatility as a multiple-state Markov switching process of order one and estimate non-diversifiable security risk (beta) in the different market volatility regimes. We test the significance of the premium of the beta risk associated with the different market regimes and find evidence of a relationship between security return an...

  14. Do limiting factors at Alaskan treelines shift with climatic regimes?

    International Nuclear Information System (INIS)

    Ohse, B; Jansen, F; Wilmking, M

    2012-01-01

    predictions of continued warming and precipitation increase at northern high latitudes hold true, the growth of Alaskan treeline trees will likely depend on the ratio of temperature and precipitation increase more than on their absolute values, as well as on the interaction of periodic regime shifts with the global warming trend. Once a climatic limitation is lifted, other factors, such as insect outbreaks or interspecific competition, might become limiting to tree growth. (letter)

  15. Prolonged Instability Prior to a Regime Shift | Science ...

    Science.gov (United States)

    Regime shifts are generally defined as the point of ‘abrupt’ change in the state of a system. However, a seemingly abrupt transition can be the product of a system reorganization that has been ongoing much longer than is evident in statistical analysis of a single component of the system. Using both univariate and multivariate statistical methods, we tested a long-term high-resolution paleoecological dataset with a known change in species assemblage for a regime shift. Analysis of this dataset with Fisher Information and multivariate time series modeling showed that there was a∼2000 year period of instability prior to the regime shift. This period of instability and the subsequent regime shift coincide with regional climate change, indicating that the system is undergoing extrinsic forcing. Paleoecological records offer a unique opportunity to test tools for the detection of thresholds and stable-states, and thus to examine the long-term stability of ecosystems over periods of multiple millennia. This manuscript explores various methods of assessing the transition between alternative states in an ecological system described by a long-term high-resolution paleoecological dataset.

  16. Dynamic two state stochastic models for ecological regime shifts

    DEFF Research Database (Denmark)

    Møller, Jan Kloppenborg; Carstensen, Niels Jacob; Madsen, Henrik

    2009-01-01

    of the model illustrates that hysteresis effect and regime shifts can be obtained for a limited range of parameter values only. The effect of multiplicative noise components entering at different levels of the model is presented and discussed. Including noise leads to very different results on the stability...

  17. Early signatures of regime shifts in gene expression dynamics

    Science.gov (United States)

    Pal, Mainak; Pal, Amit Kumar; Ghosh, Sayantari; Bose, Indrani

    2013-06-01

    Recently, a large number of studies have been carried out on the early signatures of sudden regime shifts in systems as diverse as ecosystems, financial markets, population biology and complex diseases. The signatures of regime shifts in gene expression dynamics are less systematically investigated. In this paper, we consider sudden regime shifts in the gene expression dynamics described by a fold-bifurcation model involving bistability and hysteresis. We consider two alternative models, models 1 and 2, of competence development in the bacterial population B. subtilis and determine some early signatures of the regime shifts between competence and noncompetence. We use both deterministic and stochastic formalisms for the purpose of our study. The early signatures studied include the critical slowing down as a transition point is approached, rising variance and the lag-1 autocorrelation function, skewness and a ratio of two mean first passage times. Some of the signatures could provide the experimental basis for distinguishing between bistability and excitability as the correct mechanism for the development of competence.

  18. Early signatures of regime shifts in gene expression dynamics

    International Nuclear Information System (INIS)

    Pal, Mainak; Pal, Amit Kumar; Ghosh, Sayantari; Bose, Indrani

    2013-01-01

    Recently, a large number of studies have been carried out on the early signatures of sudden regime shifts in systems as diverse as ecosystems, financial markets, population biology and complex diseases. The signatures of regime shifts in gene expression dynamics are less systematically investigated. In this paper, we consider sudden regime shifts in the gene expression dynamics described by a fold-bifurcation model involving bistability and hysteresis. We consider two alternative models, models 1 and 2, of competence development in the bacterial population B. subtilis and determine some early signatures of the regime shifts between competence and noncompetence. We use both deterministic and stochastic formalisms for the purpose of our study. The early signatures studied include the critical slowing down as a transition point is approached, rising variance and the lag-1 autocorrelation function, skewness and a ratio of two mean first passage times. Some of the signatures could provide the experimental basis for distinguishing between bistability and excitability as the correct mechanism for the development of competence. (paper)

  19. The legacy of large regime shifts in shallow lakes.

    Science.gov (United States)

    Ramstack Hobbs, Joy M; Hobbs, William O; Edlund, Mark B; Zimmer, Kyle D; Theissen, Kevin M; Hoidal, Natalie; Domine, Leah M; Hanson, Mark A; Herwig, Brian R; Cotner, James B

    2016-12-01

    Ecological shifts in shallow lakes from clear-water macrophyte-dominated to turbid-water phytoplankton-dominated are generally thought of as rapid short-term transitions. Diatom remains in sediment records from shallow lakes in the Prairie Pothole Region of North America provide new evidence that the long-term ecological stability of these lakes is defined by the legacy of large regime shifts. We examine the modern and historical stability of 11 shallow lakes. Currently, four of the lakes are in a clear-water state, three are consistently turbid-water, and four have been observed to change state from year to year (transitional). Lake sediment records spanning the past 150-200 yr suggest that (1) the diatom assemblage is characteristic of either clear or turbid lakes, (2) prior to significant landscape alteration, all of the lakes existed in a regime of a stable clear-water state, (3) lakes that are currently classified as turbid or transitional have experienced one strong regime shift over the past 150-200 yr and have since remained in a regime where turbid-water predominates, and (4) top-down impacts to the lake food-web from fish introductions appear to be the dominant driver of strong regime shifts and not increased nutrient availability. Based on our findings we demonstrate a method that could be used by lake managers to identify lakes that have an ecological history close to the clear-turbid regime threshold; such lakes might more easily be returned to a clear-water state through biomanipulation. The unfortunate reality is that many of these lakes are now part of a managed landscape and will likely require continued intervention. © 2016 by the Ecological Society of America.

  20. Body size distributions signal a regime shift in a lake ...

    Science.gov (United States)

    Communities of organisms, from mammals to microorganisms, have discontinuous distributions of body size. This pattern of size structuring is a conservative trait of community organization and is a product of processes that occur at multiple spatial and temporal scales. In this study, we assessed whether body size patterns serve as an indicator of a threshold between alternative regimes. Over the past 7000 years, the biological communities of Foy Lake (Montana,USA) have undergone a major regime shift owing to climate change. We used a palaeoecological record of diatom communities to estimate diatom sizes, and then analysed the discontinuous distribution of organism sizes over time. We used Bayesian classification and regression tree models to determine that all time intervals exhibited aggregations of sizes separated by gaps in the distribution and found a significant change in diatom body size distributions approximately 150 years before the identified ecosystem regime shift. We suggest that discontinuity analysis is a useful addition to the suite of tools for the detection of early warning signals of regime shifts. Communities of organisms from mammals to microorganisms have discontinuous distributions of body size. This pattern of size structuring is a conservative trait of community organization and is a product of processes that occur at discrete spatial and temporal scales within ecosystems. Here, a paleoecological record of diatom community change is use

  1. Decision Making under Ecological Regime Shift: An Experimental Economic Approach

    OpenAIRE

    Kawata, Yukichika

    2011-01-01

    Environmental economics postulates the assumption of homo economicus and presumes that externality occurs as a result of the rational economic activities of economic agents. This paper examines this assumption using an experimental economic approach in the context of regime shift, which has been receiving increasing attention. We observe that when externality does not exist, economic agents (subjects of experimemt) act economically rationally, but when externality exists, economic agents avoi...

  2. Regime Shift Identification of Runoff and Sediment Loads in the Yellow River Basin, China

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2014-10-01

    Full Text Available Runoff and sediment loads have exhibited significant changes over the past six decades in the Yellow River Basin, China. The current study evaluates the changing trends and regime shifts in runoff and sediment loads at both the annual and monthly time scales. The associated spatial and temporal variations are analyzed by a sequential t-test analysis of the regime shifts (STARS approach and the “breaks for additive seasonal and trend” (BFAST model using hydrological data at eight stations from the 1950s to 2011. Both runoff and sediment loads exhibit significant declines (p < 0.05, except in the upper reaches of the river near the Tangnaihai station. The regime shifts detected by the STARS approach are not completely consistent with the results from the BFAST method. In most cases, the regime shifts occurred in 1969 and 1986, due to the construction of large reservoirs. Climate change and other human activities, such as large-scale soil and water conservation measures, can result in abrupt changes in hydrological series at some stations. The trapping effects of reservoirs not only cause regime shifts of runoff and sediment loads, but also adjust their inter-annual and seasonal distributions. Various soil and water conservation measures are responsible for the significant reduction in runoff and sediment loads in the mid-lower reaches of the Yellow River Basin. In addition, water withdrawals from both river runoff and ground water play a critical role in the changing trends in runoff and indirectly alter the sediment loads. The findings provide a good reference for the effective promotion of climate change adaptation, water resources planning and river basin management.

  3. Transformational Change and Regime Shifts in the Circumpolar Arctic

    Directory of Open Access Journals (Sweden)

    Annika E. Nilsson

    2016-11-01

    Full Text Available The Arctic is changing rapidly, and there are many indications that the region is in the midst of transformational change. While some of the focus relates to impacts of climate change, rapid economic development and the potential for shifts in political and social structures in the region have also been in the limelight. This article looks at the circumpolar Arctic as a potential case of a regime shift in a large-scale social–ecological system that includes reinforcing feedbacks. A special focus is placed on governance structures, as these play an important role in social negotiations on the relationship between societies and the environment. While climate change is often portrayed as a driver of social change in the Arctic, it does not appear that the ongoing changes in the biophysical features of the Arctic region have rocked current circumpolar governance structures out of kilter. On the contrary, the ongoing climate-related changes, in particular sea ice decline, appear to have reinforced political commitment to existing legal structures. Major past social regime shifts have mainly been related to access to resources and national identity ideology, with political dynamics reinforced at times by military security considerations.

  4. Shifting balance of thermokarst lake ice regimes across the Arctic Coastal Plain of northern Alaska

    Science.gov (United States)

    Arp, Christopher D.; Jones, Benjamin M.; Lu, Zong; Whitman, Matthew S.

    2012-01-01

    The balance of thermokarst lakes with bedfast- and floating-ice regimes across Arctic lowlands regulates heat storage, permafrost thaw, winter-water supply, and over-wintering aquatic habitat. Using a time-series of late-winter synthetic aperture radar (SAR) imagery to distinguish lake ice regimes in two regions of the Arctic Coastal Plain of northern Alaska from 2003–2011, we found that 18% of the lakes had intermittent ice regimes, varying between bedfast-ice and floating-ice conditions. Comparing this dataset with a radar-based lake classification from 1980 showed that 16% of the bedfast-ice lakes had shifted to floating-ice regimes. A simulated lake ice thinning trend of 1.5 cm/yr since 1978 is believed to be the primary factor driving this form of lake change. The most profound impacts of this regime shift in Arctic lakes may be an increase in the landscape-scale thermal offset created by additional lake heat storage and its role in talik development in otherwise continuous permafrost as well as increases in over-winter aquatic habitat and winter-water supply.

  5. Emerging Trends in Development of International Information Security Regime

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    Elena S. Zinovieva

    2016-01-01

    Full Text Available The article discusses the key trends shaping the international regime on information security. International cooperation in this area at the global level encounters contradictions of state interest. The main actors of the information security are the United States, Russia, China and the EU countries (Britain, France and Germany. The main contradiction is developing between the US on one side and Russia and China on the other. EU countries occupy the middle position, gravitating to that of US. The article proves that international cooperation on information security will reflect the overall logic of the development of international cooperation, which is characterized by a new model of cooperation, with the participation of state and non-state actors, known as multi-stakeholder partnerships and multi-level cooperation. The logic of the formation of an international regime on information security is closest to the logic of the formation of the international non-proliferation regime. It is in the interest of Russia to support the trend towards regionalization of information security regime. Russia can form a regional information security regime in the former Soviet Union on the basis of the CSTO and SCO and potentially on a wider Eurasian space. Such regional regime would give Russia an opportunity to shape the international regime and closely monitor emerging information security issues in the former Soviet Union, and remove the potential threat of "color revolutions".

  6. A Review of the Detection Methods for Climate Regime Shifts

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    Qunqun Liu

    2016-01-01

    Full Text Available An abrupt climate change means that the climate system shifts from a steady state to another steady state. Study on the phenomenon and theory of the abrupt climate change is a new research field of modern climatology, and it is of great significance for the prediction of future climate change. The climate regime shift is one of the most common forms of abrupt climate change, which mainly refers to the statistical significant changes on the variable of climate system at one time scale. These detection methods can be roughly divided into five categories based on different types of abrupt changes, namely, abrupt mean value change, abrupt variance change, abrupt frequency change, abrupt probability density change, and the multivariable analysis. The main research progress of abrupt climate change detection methods is reviewed. What is more, some actual applications of those methods in observational data are provided. With the development of nonlinear science, many new methods have been presented for detecting an abrupt dynamic change in recent years, which is useful supplement for the abrupt change detection methods.

  7. Pre-"peak water" time in the southwest Yukon: when cryospheric changes trigger hydrological regime shifts

    Science.gov (United States)

    Baraer, M.; Chesnokova, A.; Huh, K. I.; Laperriere-Robillard, T.

    2017-12-01

    Saint-Elias Mountains host numerous cryospheric systems such as glaciers, seasonal and perennial snow cover, permafrost, aufeis, and different forms of buried ice. Those systems are very sensitive to climate changes and exhibit ongoing reduction in extent and/or changes in formation/ablation times. Because they highly influence the hydrological regimes of rivers, cryospheric changes raise concerns about consequences for regional water resources and ecosystems. The present study combines historical data analysis and hydrological modeling in order to estimate how cryospheric changes impact hydrological regimes at eight watersheds of different glacier cover (0- 30%) in the southwest Yukon. Methods combine traditional hydrograph analysis techniques and more advance techniques such as Fast Fourier Transform filters used to isolate significant trends in discharge properties from noise or climatic oscillations. Measured trends in discharge variables are connected to cryospheric changes by using a water balance / peak water model (Baraer et al., 2012), here adapted to the main cryospheric systems that characterize the southwest Yukon.Results show three distinct hydrological regimes for (1) non glacierized, (2) glacierized, and (3) major lakes hosting catchments. The studied glacierized catchments have not passed the "peak water" yet and still exhibit increases in yearly and late summer discharges and a decrease in runoff variability. All watersheds show an increase in winter discharge and a snowmelt-driven shift of yearly peak discharge toward earlier in the season. The study suggests that, in a couple of decades, water resources and dependent ecosystems will face the combined effects of (A) a shift in the contribution trend from declining perennial cryospheric systems and (B) continuing alteration of the contribution from the seasonal cryospheric systems.

  8. Projected Regime Shift in Arctic Cloud and Water Vapor Feedbacks

    Science.gov (United States)

    Chen, Yonghua; Miller, James R.; Francis, Jennifer; Russel, Gary L.

    2011-01-01

    The Arctic climate is changing faster than any other large-scale region on Earth. A variety of positive feedback mechanisms are responsible for the amplification, most of which are linked with changes in snow and ice cover, surface temperature (T(sub s)), atmospheric water vapor (WV), and cloud properties. As greenhouse gases continue to accumulate in the atmosphere, air temperature and water vapor content also increase, leading to a warmer surface and ice loss, which further enhance evaporation and WV. Many details of these interrelated feedbacks are poorly understood, yet are essential for understanding the pace and regional variations in future Arctic change. We use a global climate model (Goddard Institute for Space Studies, Atmosphere-Ocean Model) to examine several components of these feedbacks, how they vary by season, and how they are projected to change through the 21st century. One positive feedback begins with an increase in T(sub s) that produces an increase in WV, which in turn increases the downward longwave flux (DLF) and T(sub s), leading to further evaporation. Another associates the expected increases in cloud cover and optical thickness with increasing DLF and T(sub s). We examine the sensitivities between DLF and other climate variables in these feedbacks and find that they are strongest in the non-summer seasons, leading to the largest amplification in Ts during these months. Later in the 21st century, however, DLF becomes less sensitive to changes in WV and cloud optical thickness, as they cause the atmosphere to emit longwave radiation more nearly as a black body. This regime shift in sensitivity implies that the amplified pace of Arctic change relative to the northern hemisphere could relax in the future.

  9. Interacting Regional-Scale Regime Shifts for Biodiversity and Ecosystem Services

    NARCIS (Netherlands)

    Leadley, P.; Proenca, V.; Fernandez-Manjarres, J.; Pereira, H.M.; Alkemade, J.R.M.; Biggs, R.; Bruley, E.; Cheung, W.; Cooper, D.; Figueiredo, J.; Gilman, E.; Guenette, S.; Hurtt, G.; Mbow, C.; Oberdorff, T.; Revenga, C.; Scharlemann, J.P.W.; Scholes, R.; Smith, M.S.; Sumaila, U.R.; Walpole, M.

    2014-01-01

    Current trajectories of global change may lead to regime shifts at regional scales, driving coupled human-environment systems to highly degraded states in terms of biodiversity, ecosystem services, and human well-being. For business-as-usual socioeconomic development pathways, regime shifts are

  10. Hysteresis, regime shifts, and non-stationarity in aquifer recharge-storage-discharge systems

    Science.gov (United States)

    Klammler, Harald; Jawitz, James; Annable, Michael; Hatfield, Kirk; Rao, Suresh

    2016-04-01

    Based on physical principles and geological information we develop a parsimonious aquifer model for Silver Springs, one of the largest karst springs in Florida. The model structure is linear and time-invariant with recharge, aquifer head (storage) and spring discharge as dynamic variables at the springshed (landscape) scale. Aquifer recharge is the hydrological driver with trends over a range of time scales from seasonal to multi-decadal. The freshwater-saltwater interaction is considered as a dynamic storage mechanism. Model results and observed time series show that aquifer storage causes significant rate-dependent hysteretic behavior between aquifer recharge and discharge. This leads to variable discharge per unit recharge over time scales up to decades, which may be interpreted as a gradual and cyclic regime shift in the aquifer drainage behavior. Based on field observations, we further amend the aquifer model by assuming vegetation growth in the spring run to be inversely proportional to stream velocity and to hinder stream flow. This simple modification introduces non-linearity into the dynamic system, for which we investigate the occurrence of rate-independent hysteresis and of different possible steady states with respective regime shifts between them. Results may contribute towards explaining observed non-stationary behavior potentially due to hydrological regime shifts (e.g., triggered by gradual, long-term changes in recharge or single extreme events) or long-term hysteresis (e.g., caused by aquifer storage). This improved understanding of the springshed hydrologic response dynamics is fundamental for managing the ecological, economic and social aspects at the landscape scale.

  11. Variance as a Leading Indicator of Regime Shift in Ecosystem Services

    Directory of Open Access Journals (Sweden)

    William A. Brock

    2006-12-01

    Full Text Available Many environmental conflicts involve pollutants such as greenhouse gas emissions that are dispersed through space and cause losses of ecosystem services. As pollutant emissions rise in one place, a spatial cascade of declining ecosystem services can spread across a larger landscape because of the dispersion of the pollutant. This paper considers the problem of anticipating such spatial regime shifts by monitoring time series of the pollutant or associated ecosystem services. Using such data, it is possible to construct indicators that rise sharply in advance of regime shifts. Specifically, the maximum eigenvalue of the variance-covariance matrix of the multivariate time series of pollutants and ecosystem services rises prior to the regime shift. No specific knowledge of the mechanisms underlying the regime shift is needed to construct the indicator. Such leading indicators of regime shifts could provide useful signals to management agencies or to investors in ecosystem service markets.

  12. Early signatures of regime shifts in complex dynamical systems

    Indian Academy of Sciences (India)

    2015-02-05

    Feb 5, 2015 ... journal of. February 2015 ... populations, financial markets, complex diseases and gene circuits. ... A recent exhaustive analysis of recorded ecosystem shifts points to an approach- .... The quantitative estimation of these.

  13. Land-use regime shifts: an analytical framework and agenda for future land-use research

    Directory of Open Access Journals (Sweden)

    Navin Ramankutty

    2016-06-01

    Full Text Available A key research frontier in global change research lies in understanding processes of land change to inform predictive models of future land states. We believe that significant advances in the field are hampered by limited attention being paid to critical points of change termed land-use regime shifts. We present an analytical framework for understanding land-use regime shifts. We survey historical events of land change and perform in-depth case studies of soy and shrimp development in Latin America to demonstrate the role of preconditions, triggers, and self-reinforcing processes in driving land-use regime shifts. Whereas the land-use literature demonstrates a good understanding of within-regime dynamics, our understanding of the drivers of land-use regime shifts is limited to ex post facto explications. Theoretical and empirical advances are needed to better understand the dynamics and implications of land-use regime shifts. We draw insights from the regime-shifts literature to propose a research agenda for studying land change.

  14. Anticipating regime shifts in gene expression: The case of an autoactivating positive feedback loop

    Science.gov (United States)

    Sharma, Yogita; Dutta, Partha Sharathi; Gupta, A. K.

    2016-03-01

    Considerable evidence suggests that anticipating sudden shifts from one state to another in bistable dynamical systems is a challenging task; examples include ecosystems, financial markets, and complex diseases. In this paper, we investigate the effects of additive, multiplicative, and cross-correlated stochastic perturbations on determining the regime shifts in a bistable gene regulatory system, which gives rise to two distinct states of low and high concentrations of protein. We obtain the stationary probability density and mean first-passage time of the system. We show that increasing the additive (multiplicative) noise intensity induces a regime shift from a low (high) to a high (low) protein concentration state. However, an increase in the cross-correlation intensity always induces regime shifts from a high to a low protein concentration state. For both bifurcation-induced (often called the tipping point) and noise-induced (called stochastic switching) regime shifts, we further explore the robustness of recently developed critical-down-based early warning signal (EWS) indicators (e.g., rising variance and lag-1 autocorrelation) on our simulated time-series data. We identify that using EWS indicators, prediction of an impending bifurcation-induced regime shift is relatively easier than that of a noise-induced regime shift in the considered system. Moreover, the success of EWS indicators also strongly depends upon the nature of the noise.

  15. Regime shifts and panarchies in regional scale social ...

    Science.gov (United States)

    In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises,

  16. Regime shifts limit the predictability of land-system change

    DEFF Research Database (Denmark)

    Müller, Daniel; Sun, Zhanli; Vongvisouk, Thoumthone

    2014-01-01

    Payment schemes for ecosystem services such as Reducing Emissions from Deforestation and forest Degradation (REDD) rely on the prediction of ‘business-as-usual’ scenarios to ensure that emission reductions from carbon credits are additional. However, land systems often undergo periods of nonlinear...... and abrupt change that invalidate predictions calibrated on past trends. Rapid land-system change can occur when critical thresholds in broad-scale underlying drivers such as commodity prices and climate conditions are crossed or when sudden events such as political change or natural disasters punctuate long...

  17. Assessing water quality trends in catchments with contrasting hydrological regimes

    Science.gov (United States)

    Sherriff, Sophie C.; Shore, Mairead; Mellander, Per-Erik

    2016-04-01

    classes yielded higher flow-weighted SS concentrations as source availability was combined with enhanced transport efficiency of specific pathways. However, discrepancies between monthly rainfall totals and monthly flow-weighted pollutant export are likely due to event scale variability in storm characteristics, lag times and source availability. This methodology was useful to indicate sub-annual water quality trends due to agricultural land use changes in multiple catchments with contrasting hydrological regimes. Consequently, critical periods of pollutant transfer can be targeted to develop sustainable environmental management strategies.

  18. The Regime Shift Associated with the 2004–2008 US Housing Market Bubble

    Science.gov (United States)

    Cheong, Siew Ann

    2016-01-01

    The Subprime Bubble preceding the Subprime Crisis of 2008 was fueled by risky lending practices, manifesting in the form of a large abrupt increase in the proportion of subprime mortgages issued in the US. This event also coincided with critical slowing down signals associated with instability, which served as evidence of a regime shift or phase transition in the US housing market. Here, we show that the US housing market underwent a regime shift between alternate stable states consistent with the observed critical slowing down signals. We modeled this regime shift on a universal transition path and validated the model by estimating when the bubble burst. Additionally, this model reveals loose monetary policy to be a plausible cause of the phase transition, implying that the bubble might have been deflatable by a timely tightening of monetary policy. PMID:27583633

  19. New trends of activity on supporting of non-proliferation regime

    International Nuclear Information System (INIS)

    Issaeva, G.M.; Tyupkina, O.G.

    2002-01-01

    Taking into account the necessity of all possible strengthening of non-proliferation regimes Kazakhstan participates in a number of agreements and associations: Nuclear Non-proliferation Treaty, Comprehensive Test-Ban-Treaty, International Atomic Energy Agency, Nuclear Supplier Group, Missile Technology Control Regime, Conference on Disarmament, etc. The Cooperative Threat Reduction Program (CTR) greatly influenced on the development on non-proliferation regime in Kazakhstan. During initial stage of CTR activity (1993-1995) military projects prevailed. Later (1995-1997) the projects on liquidation of infrastructure for nuclear and bio- weapons were successfully realized. Last years, since 1999, the attention was shifted towards proliferation prevention of hazardous nuclear and biological materials. Recent terrorist acts and world community activity on global safety strengthening underline an urgency of quite new problems that entirely applied to Kazakhstan: monitoring of hazardous materials; enhancement of safety systems of 'risky' facilities and technologies; creation and/or upgrading of safety systems for industry infrastructure. The proposals of these new trends of non-proliferation have been developed. Development of physical protection system for oil and gas industry infrastructure of Kazakhstan based on safety concepts of nuclear facilities; Evaluation of radionuclide contamination and safety of oil and gas facilities of the Caspian region; Counteraction to nuclear materials proliferation; Cooperative approaches in preventing/reducing of illicit trafficking and use of WMD-related explosive materials. Implementation of the project would make of substantial contribution to successful solution of either regional or global safety problem

  20. Regime shifts in demersal assemblages of the Benguela Current Large Marine Ecosystem: a comparative assessment

    DEFF Research Database (Denmark)

    Kirkman, Stephen P.; Yemane, Dawit; Atkinson, Lara J.

    2015-01-01

    Using long‐term survey data, changes in demersal faunal communities in the Benguela Current Large Marine Ecosystem were analysed at community and population levels to provide a comparative overview of the occurrence and timing of regime shifts. For South Africa, the timing of a community‐level sh......Using long‐term survey data, changes in demersal faunal communities in the Benguela Current Large Marine Ecosystem were analysed at community and population levels to provide a comparative overview of the occurrence and timing of regime shifts. For South Africa, the timing of a community...

  1. Catastrophic regime shifts in model ecological communities are true phase transitions

    International Nuclear Information System (INIS)

    Capitán, J A; Cuesta, J A

    2010-01-01

    Ecosystems often undergo abrupt regime shifts in response to gradual external changes. These shifts are theoretically understood as a regime switch between alternative stable states of the ecosystem dynamical response to smooth changes in external conditions. Usual models introduce nonlinearities in the macroscopic dynamics of the ecosystem that lead to different stable attractors among which the shift takes place. Here we propose an alternative explanation of catastrophic regime shifts based on a recent model that pictures ecological communities as systems in continuous fluctuation, according to certain transition probabilities, between different micro-states in the phase space of viable communities. We introduce a spontaneous extinction rate that accounts for gradual changes in external conditions, and upon variations on this control parameter the system undergoes a regime shift with similar features to those previously reported. Under our microscopic viewpoint we recover the main results obtained in previous theoretical and empirical work (anomalous variance, hysteresis cycles, trophic cascades). The model predicts a gradual loss of species in trophic levels from bottom to top near the transition. But more importantly, the spectral analysis of the transition probability matrix allows us to rigorously establish that we are observing the fingerprints, in a finite size system, of a true phase transition driven by background extinctions

  2. Trophic cascades triggered by overfishing reveal possible mechanisms of ecosystem regime shifts.

    Science.gov (United States)

    Daskalov, Georgi M; Grishin, Alexander N; Rodionov, Sergei; Mihneva, Vesselina

    2007-06-19

    Large-scale transitions between alternative states in ecosystems are known as regime shifts. Once described as healthy and dominated by various marine predators, the Black Sea ecosystem by the late 20th century had experienced anthropogenic impacts such as heavy fishing, cultural eutrophication, and invasions by alien species. We studied changes related to these "natural experiments" to reveal the mechanisms of regime shifts. Two major shifts were detected, the first related to a depletion of marine predators and the second to an outburst of the alien comb jelly Mnemiopsis leidyi; both shifts were triggered by intense fishing resulting in system-wide trophic cascades. The complex nature of ecosystem responses to human activities calls for more elaborate approaches than currently provided by traditional environmental and fisheries management. This implies challenging existing practices and implementing explanatory models of ecosystem interactions that can better reconcile conservation and ecosystem management ideals.

  3. The 3000-4000 cal. BP anthropogenic shift in fire regime in the French Pyrenees.

    Science.gov (United States)

    Rius, D.; Vannière, B.; Galop, D.; Richard, H.

    2009-04-01

    Fire is a key disturbing agent in a wide range of ecosystems: boreal biome (Pitkanen, 2000), Mediterranean area (Colombaroli et al., 2008) as well as temperate European mountain zones (Tinner et al., 1999). During the Holocene, climate may control fire regime by both ignition and fire spread-favouring conditions (i.e. composition, structure and moisture of biomass) whereas man may change charcoal accumulation patterns through type and intensity of agro-pastoral activities. In western and Mediterranean Europe, single sites charcoal analysis recorded the anthropogenic forcing over fire regime broadly between the mid and the late-Holocene. Turner et al (2008) showed that climate and fire had been disconnected since 1700 cal. BP in Turkey. In central Swiss, Mean Fire Interval decreased by two times 2000 years ago due to increasing human impact (Stahli et al., 2006). In Italy, climate and man have had a combined influence on fire-hazard since ca 4000 cal. BP (Vannière et al., 2008). In the Pyrenees Mountains, the linkage between agro-pastoral practices and fire could be dated back to ca 4000-3000 cal. BP with a clear succession of a clearance phase (high fire frequency) followed by a quite linear trend throughout Middle Ages and Modern times corresponding to a change in fire use (Vanniere et al., 2001; Galop et al., 2002, Rius et al., in press). The quantification of fire regimes parameters such as frequency with robust methodological tools (Inferred Fire Frequency, Mean Fire Interval) is needed to understand and characterise such shifts. Here we present two sequences from the Lourdes basin (col d'Ech peat bog) and from the occidental Pyrenees (Gabarn peat bog), which cover the last 9000 years with high temporal resolution. The main goals of this study were to (1) assess control factors of fire regime throughout the lateglacial and Holocene (climate and/or man) on the local scale, (2) evidence the local/regional significance of these control factors , (3) discuss the

  4. Critical slowing down associated with regime shifts in the US housing market

    Science.gov (United States)

    Tan, James Peng Lung; Cheong, Siew Siew Ann

    2014-02-01

    Complex systems are described by a large number of variables with strong and nonlinear interactions. Such systems frequently undergo regime shifts. Combining insights from bifurcation theory in nonlinear dynamics and the theory of critical transitions in statistical physics, we know that critical slowing down and critical fluctuations occur close to such regime shifts. In this paper, we show how universal precursors expected from such critical transitions can be used to forecast regime shifts in the US housing market. In the housing permit, volume of homes sold and percentage of homes sold for gain data, we detected strong early warning signals associated with a sequence of coupled regime shifts, starting from a Subprime Mortgage Loans transition in 2003-2004 and ending with the Subprime Crisis in 2007-2008. Weaker signals of critical slowing down were also detected in the US housing market data during the 1997-1998 Asian Financial Crisis and the 2000-2001 Technology Bubble Crisis. Backed by various macroeconomic data, we propose a scenario whereby hot money flowing back into the US during the Asian Financial Crisis fueled the Technology Bubble. When the Technology Bubble collapsed in 2000-2001, the hot money then flowed into the US housing market, triggering the Subprime Mortgage Loans transition in 2003-2004 and an ensuing sequence of transitions. We showed how this sequence of couple transitions unfolded in space and in time over the whole of US.

  5. Modelling regime shifts in the southern Benguela: a frame-based ...

    African Journals Online (AJOL)

    Modelling regime shifts in the southern Benguela: a frame-based approach. MD Smith, A Jarre. Abstract. This study explores the usefulness of a frame-based modelling approach in the southern Benguela upwelling ecosystem, with four frames describing observed small pelagic fish dominance patterns. We modelled the ...

  6. Regime shifts in the marine environment: the scientific basis and political context.

    Science.gov (United States)

    Kraberg, Alexandra C; Wasmund, Norbert; Vanaverbeke, Jan; Schiedek, Doris; Wiltshire, Karen H; Mieszkowska, Nova

    2011-01-01

    Regime shifts in the marine environment have recently received much attention. To date, however, few large-scale meta-analyses have been carried out due to insufficient data coverage and integration between sustained observational datasets because of diverse methodologies used in data collection, recording and archival. Here we review the available data on regime shifts globally, followed by a review of current and planned policies with relevance to regime shifts. We then focus on the North and Baltic Seas, providing examples of existing efforts for data integration in the MarBEF Network of Excellence. Existing gaps in data coverage are identified, and the added value from meta-analyses of multiple datasets demonstrated using examples from the MarBEF integrated data project LargeNet. We discuss whether these efforts are addressing current policy needs and close with recommendations for future integrated data networks to increase our ability to understand, identify and predict recent and future regime shifts. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Probe-controlled soliton frequency shift in the regime of optical event horizon

    DEFF Research Database (Denmark)

    Gu, Jie; Guo, Hairun; Wang, Shaofei

    2015-01-01

    In optical analogy of the event horizon, temporal pulse collision and mutual interactions are mainly between an intense solitary wave (soliton) and a dispersive probe wave. In such a regime, here we numerically investigate the probe-controlled soliton frequency shift as well as the soliton self...

  8. Challenges in the participatory assessment of sustainable management practices in dryland ecosystems under regime shifts

    Science.gov (United States)

    Jucker Riva, Matteo; Schwilch, Gudrun; Liniger, Hanspeter

    2015-04-01

    Regime shifts, defined as a radical and persistent reconfiguration of an ecosystem following a disturbance, have been acknowledged by scientists as a very important aspect of the dynamic of ecosystems. However, their consideration in land management planning remains marginal and limited to specific processes and systems. Current research focuses on mathematical modeling and statistical analysis of spatio-temporal data for specific environmental variables. These methods do not fulfill the needs of land managers, who are confronted with a multitude of processes and pressure types and require clear and simple strategies to prevent regime shift or to increase the resilience of their environment. The EU-FP7 CASCADE project is looking at regime shifts of dryland ecosystems in southern Europe and specifically focuses on rangeland and forest systems which are prone to various land degradation threats. One of the aims of the project is to evaluate the impact of different management practices on the dynamic of the environment in a participatory manner, including a multi-stakeholder evaluation of the state of the environment and of the management potential. To achieve this objective we have organized several stakeholder meetings and we have compiled a review of management practices using the WOCAT methodology, which enables merging scientific and land users knowledge. We highlight here the main challenges we have encountered in applying the notion of regime shift to real world socio-ecological systems and in translating related concepts such as tipping points, stable states, hysteresis and resilience to land managers, using concrete examples from CASCADE study sites. Secondly, we explore the advantages of including land users' knowledge in the scientific understanding of regime shifts. Moreover, we discuss useful alternative concepts and lessons learnt that will allow us to build a participatory method for the assessment of resilient management practices in specific socio

  9. Representing Sudden Shifts in Intensive Dyadic Interaction Data Using Differential Equation Models with Regime Switching.

    Science.gov (United States)

    Chow, Sy-Miin; Ou, Lu; Ciptadi, Arridhana; Prince, Emily B; You, Dongjun; Hunter, Michael D; Rehg, James M; Rozga, Agata; Messinger, Daniel S

    2018-06-01

    A growing number of social scientists have turned to differential equations as a tool for capturing the dynamic interdependence among a system of variables. Current tools for fitting differential equation models do not provide a straightforward mechanism for diagnosing evidence for qualitative shifts in dynamics, nor do they provide ways of identifying the timing and possible determinants of such shifts. In this paper, we discuss regime-switching differential equation models, a novel modeling framework for representing abrupt changes in a system of differential equation models. Estimation was performed by combining the Kim filter (Kim and Nelson State-space models with regime switching: classical and Gibbs-sampling approaches with applications, MIT Press, Cambridge, 1999) and a numerical differential equation solver that can handle both ordinary and stochastic differential equations. The proposed approach was motivated by the need to represent discrete shifts in the movement dynamics of [Formula: see text] mother-infant dyads during the Strange Situation Procedure (SSP), a behavioral assessment where the infant is separated from and reunited with the mother twice. We illustrate the utility of a novel regime-switching differential equation model in representing children's tendency to exhibit shifts between the goal of staying close to their mothers and intermittent interest in moving away from their mothers to explore the room during the SSP. Results from empirical model fitting were supplemented with a Monte Carlo simulation study to evaluate the use of information criterion measures to diagnose sudden shifts in dynamics.

  10. Predicting climate-driven regime shifts versus rebound potential in coral reefs.

    Science.gov (United States)

    Graham, Nicholas A J; Jennings, Simon; MacNeil, M Aaron; Mouillot, David; Wilson, Shaun K

    2015-02-05

    Climate-induced coral bleaching is among the greatest current threats to coral reefs, causing widespread loss of live coral cover. Conditions under which reefs bounce back from bleaching events or shift from coral to algal dominance are unknown, making it difficult to predict and plan for differing reef responses under climate change. Here we document and predict long-term reef responses to a major climate-induced coral bleaching event that caused unprecedented region-wide mortality of Indo-Pacific corals. Following loss of >90% live coral cover, 12 of 21 reefs recovered towards pre-disturbance live coral states, while nine reefs underwent regime shifts to fleshy macroalgae. Functional diversity of associated reef fish communities shifted substantially following bleaching, returning towards pre-disturbance structure on recovering reefs, while becoming progressively altered on regime shifting reefs. We identified threshold values for a range of factors that accurately predicted ecosystem response to the bleaching event. Recovery was favoured when reefs were structurally complex and in deeper water, when density of juvenile corals and herbivorous fishes was relatively high and when nutrient loads were low. Whether reefs were inside no-take marine reserves had no bearing on ecosystem trajectory. Although conditions governing regime shift or recovery dynamics were diverse, pre-disturbance quantification of simple factors such as structural complexity and water depth accurately predicted ecosystem trajectories. These findings foreshadow the likely divergent but predictable outcomes for reef ecosystems in response to climate change, thus guiding improved management and adaptation.

  11. Preventing regime shifts on the Colorado Plateau: Application of ecological threshold concepts to land management decision making

    Science.gov (United States)

    Investigating the mechanisms responsible for ecological thresholds is essential to understanding processes leading to ecosystem regime shifts. Dryland ecosystems are especially prone to threshold behavior wherein stressor-mediated alteration of patterns and processes can shift systems to alternative...

  12. Development and current trends in the international nonproliferation regime

    International Nuclear Information System (INIS)

    Sessoms, A.L.

    1984-01-01

    The IAEA and its safeguards system is placed into a historical perspective. A personal perspective on the nonproliferation regime and on the Agency's role in it is then presented. This is done initially by discussing some of the landmark events in the history of the nonproliferation regime. Subsequently some of the history of arms control agreements and of the role of the IAEA are noted. Then political motivations of state and ways the Agency has an impact in the political nonproliferation sphere are addressed

  13. Motional frequency shifts of trapped ions in the Lamb-Dicke regime

    International Nuclear Information System (INIS)

    Lizuain, I.; Muga, J. G.; Eschner, J.

    2007-01-01

    First order Doppler effects are usually ignored in laser driven trapped ions when the recoil frequency is much smaller than the trapping frequency (Lamb-Dicke regime). This means that the central, carrier excitation band is supposed to be unaffected by vibronic transitions in which the vibrational number changes. While this is strictly true in the Lamb-Dicke limit (infinitely tight confinement), the vibronic transitions do play a role in the Lamb-Dicke regime. In this paper we quantify the asymptotic behavior of their effect with respect to the Lamb-Dicke parameter. In particular, we give analytical expressions for the frequency shift, 'pulling' or 'pushing', produced in the carrier absorption band by the vibronic transitions both for Rabi and Ramsey schemes. This shift is shown to be independent of the initial vibrational state

  14. An algorithm for engineering regime shifts in one-dimensional dynamical systems

    Science.gov (United States)

    Tan, James P. L.

    2018-01-01

    Regime shifts are discontinuous transitions between stable attractors hosting a system. They can occur as a result of a loss of stability in an attractor as a bifurcation is approached. In this work, we consider one-dimensional dynamical systems where attractors are stable equilibrium points. Relying on critical slowing down signals related to the stability of an equilibrium point, we present an algorithm for engineering regime shifts such that a system may escape an undesirable attractor into a desirable one. We test the algorithm on synthetic data from a one-dimensional dynamical system with a multitude of stable equilibrium points and also on a model of the population dynamics of spruce budworms in a forest. The algorithm and other ideas discussed here contribute to an important part of the literature on exercising greater control over the sometimes unpredictable nature of nonlinear systems.

  15. Millennial-scale plankton regime shifts in the subtropical North Pacific Ocean.

    Science.gov (United States)

    McMahon, Kelton W; McCarthy, Matthew D; Sherwood, Owen A; Larsen, Thomas; Guilderson, Thomas P

    2015-12-18

    Climate change is predicted to alter marine phytoplankton communities and affect productivity, biogeochemistry, and the efficacy of the biological pump. We reconstructed high-resolution records of changing plankton community composition in the North Pacific Ocean over the past millennium. Amino acid-specific δ(13)C records preserved in long-lived deep-sea corals revealed three major plankton regimes corresponding to Northern Hemisphere climate periods. Non-dinitrogen-fixing cyanobacteria dominated during the Medieval Climate Anomaly (950-1250 Common Era) before giving way to a new regime in which eukaryotic microalgae contributed nearly half of all export production during the Little Ice Age (~1400-1850 Common Era). The third regime, unprecedented in the past millennium, began in the industrial era and is characterized by increasing production by dinitrogen-fixing cyanobacteria. This picoplankton community shift may provide a negative feedback to rising atmospheric carbon dioxide concentrations. Copyright © 2015, American Association for the Advancement of Science.

  16. Evaluating trophic cascades as drivers of regime shifts in different ocean ecosystems

    Science.gov (United States)

    Pershing, Andrew J.; Mills, Katherine E.; Record, Nicholas R.; Stamieszkin, Karen; Wurtzell, Katharine V.; Byron, Carrie J.; Fitzpatrick, Dominic; Golet, Walter J.; Koob, Elise

    2015-01-01

    In ecosystems that are strongly structured by predation, reducing top predator abundance can alter several lower trophic levels—a process known as a trophic cascade. A persistent trophic cascade also fits the definition of a regime shift. Such ‘trophic cascade regime shifts' have been reported in a few pelagic marine systems—notably the Black Sea, Baltic Sea and eastern Scotian Shelf—raising the question of how common this phenomenon is in the marine environment. We provide a general methodology for distinguishing top-down and bottom-up effects and apply this methodology to time series from these three ecosystems. We found evidence for top-down forcing in the Black Sea due primarily to gelatinous zooplankton. Changes in the Baltic Sea are primarily bottom-up, strongly structured by salinity, but top-down forcing related to changes in cod abundance also shapes the ecosystem. Changes in the eastern Scotian Shelf that were originally attributed to declines in groundfish are better explained by changes in stratification. Our review suggests that trophic cascade regime shifts are rare in open ocean ecosystems and that their likelihood increases as the residence time of water in the system increases. Our work challenges the assumption that negative correlation between consecutive trophic levels implies top-down forcing.

  17. Impacts of extensive driftnet fishery and late 1990s climate regime shift on dominant epipelagic nekton in the Transition Region and Subtropical Frontal Zone: Implications for fishery management

    Science.gov (United States)

    Ichii, T.; Nishikawa, H.; Igarashi, H.; Okamura, H.; Mahapatra, K.; Sakai, M.; Wakabayashi, T.; Inagake, D.; Okada, Y.

    2017-01-01

    We investigated the impacts of extensive anthropogenic (high seas driftnet squid fishery) and natural (late 1990s major climate regime shift) events on dominant epipelagic fish, squid, and shark in the central North Pacific Transition Region based on a driftnet survey covering the years 1979-2006. Fishing was conducted by Japan, Korea and Taiwan to target neon flying squid in the period 1979-1992, resulting in a decline in stocks of the target species and non-target species (Pacific pomfret and juvenile blue shark), which were by-catch of this fishery. The catch was found to be at the maximum sustainable yield (MSY) level for neon flying squid, the underfished level for juvenile blue shark, but the overfished level for Pacific pomfret. The MSY of Pacific pomfret indicated that this species is more susceptible to exploitation than previously considered. In response to the late 1990s regime shift, neon flying squid and Pacific saury showed low stock levels in 1999-2002 and 1998-2002, respectively, as a result of reduced productivity in their nursery grounds (the Subtropical Frontal Zone and Kuroshio Extension Bifurcation Region, respectively). On the other hand, Pacific pomfret showed no decreasing trend in stock during the low- and intermediate-productivity regimes because of the high productivity of their main spawning/nursery ground (Transition Zone Chlorophyll Front), which was independent of the regime shifts. Thus, squid and saury appear to be more susceptible to the regime shift than pomfret. We discuss the implications for stock management of the species-specific responses to the fishery and the regime shift.

  18. Recent surface cooling in the Yellow and East China Seas and the associated North Pacific climate regime shift

    Science.gov (United States)

    Kim, Yong Sun; Jang, Chan Joo; Yeh, Sang-Wook

    2018-03-01

    The Yellow and East China Seas (YECS) are widely believed to have experienced robust, basin-scale warming over the last few decades. However, the warming reached a peak in the late 1990s, followed by a significant cooling trend. In this study, we investigated the characteristics of this low-frequency sea surface temperature (SST) variance and its dynamic relationship with large-scale climate variability through cyclostationary orthogonal function analysis for the 1982-2014 period. Both regressed surface winds on the primary mode of the YECS SST and trends in air-sea heat fluxes demonstrate that the intensification of the northerly winds in winter contribute largely to the recent cooling trend by increasing heat loss to the atmosphere. As a localized oceanic response to these winds, the upwind flow seems to bring warm waters and partially counteracts the basin-scale cooling, thus contributing to a weakening of the cooling trend along the central trough of the Yellow Sea. In the context of the large-scale climate variabilities, a strong relationship between the YECS SST variability and Pacific Decadal Oscillation (PDO) became weak considerably during the recent cooling period after the late 1990s as the PDO signals appeared to be confined within the eastern basin of the North Pacific in association with the regime shift. In addition to this decoupling of the YECS SST from the PDO, the intensifying Siberian High pressure system likely caused the enhanced northerly winds, leading to the recent cooling trend. These findings highlight relative roles of the PDO and the Siberian High in shaping the YECS SST variance through the changes in the large-scale atmospheric circulation and attendant oceanic advection.

  19. Regime shifts under forcing of non-stationary attractors: Conceptual model and case studies in hydrologic systems.

    Science.gov (United States)

    Park, Jeryang; Rao, P Suresh C

    2014-11-15

    We present here a conceptual model and analysis of complex systems using hypothetical cases of regime shifts resulting from temporal non-stationarity in attractor strengths, and then present selected published cases to illustrate such regime shifts in hydrologic systems (shallow aquatic ecosystems; water table shifts; soil salinization). Complex systems are dynamic and can exist in two or more stable states (or regimes). Temporal variations in state variables occur in response to fluctuations in external forcing, which are modulated by interactions among internal processes. Combined effects of external forcing and non-stationary strengths of alternative attractors can lead to shifts from original to alternate regimes. In systems with bi-stable states, when the strengths of two competing attractors are constant in time, or are non-stationary but change in a linear fashion, regime shifts are found to be temporally stationary and only controlled by the characteristics of the external forcing. However, when attractor strengths change in time non-linearly or vary stochastically, regime shifts in complex systems are characterized by non-stationary probability density functions (pdfs). We briefly discuss implications and challenges to prediction and management of hydrologic complex systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Volcano-induced regime shifts in millennial tree-ring chronologies from northeastern North America.

    Science.gov (United States)

    Gennaretti, Fabio; Arseneault, Dominique; Nicault, Antoine; Perreault, Luc; Bégin, Yves

    2014-07-15

    Dated records of ice-cap growth from Arctic Canada recently suggested that a succession of strong volcanic eruptions forced an abrupt onset of the Little Ice Age between A.D. 1275 and 1300 [Miller GH, et al. (2012) Geophys Res Lett 39(2):L02708, 10.1029/2011GL050168]. Although this idea is supported by simulation experiments with general circulation models, additional support from field data are limited. In particular, the Northern Hemisphere network of temperature-sensitive millennial tree-ring chronologies, which principally comprises Eurasian sites, suggests that the strongest eruptions only caused cooling episodes lasting less than about 10 y. Here we present a new network of millennial tree-ring chronologies from the taiga of northeastern North America, which fills a wide gap in the network of the Northern Hemisphere's chronologies suitable for temperature reconstructions and supports the hypothesis that volcanoes triggered both the onset and the coldest episode of the Little Ice Age. Following the well-expressed Medieval Climate Anomaly (approximately A.D. 910-1257), which comprised the warmest decades of the last millennium, our tree-ring-based temperature reconstruction displays an abrupt regime shift toward lower average summer temperatures precisely coinciding with a series of 13th century eruptions centered around the 1257 Samalas event and closely preceding ice-cap expansion in Arctic Canada. Furthermore, the successive 1809 (unknown volcano) and 1815 (Tambora) eruptions triggered a subsequent shift to the coldest 40-y period of the last 1100 y. These results confirm that series of large eruptions may cause region-specific regime shifts in the climate system and that the climate of northeastern North America is especially sensitive to volcanic forcing.

  1. Benthic-planktonic coupling, regime shifts, and whole-lake primary production in shallow lakes.

    Science.gov (United States)

    Genkai-Kato, Motomi; Vadeboncoeur, Yvonne; Liboriussen, Lone; Jeppesen, Erik

    2012-03-01

    Alternative stable states in shallow lakes are typically characterized by submerged macrophyte (clear-water state) or phytoplankton (turbid state) dominance. However, a clear-water state may occur in eutrophic lakes even when macrophytes are absent. To test whether sediment algae could cause a regime shift in the absence of macrophytes, we developed a model of benthic (periphyton) and planktonic (phytoplankton) primary production using parameters derived from a shallow macrophyte-free lake that shifted from a turbid to a clear-water state following fish removal (biomanipulation). The model includes a negative feedback effect of periphyton on phosphorus (P) release from sediments. This in turn induces a positive feedback between phytoplankton production and P release. Scenarios incorporating a gradient of external P loading rates revealed that (1) periphyton and phytoplankton both contributed substantially to whole-lake production over a broad range of external P loading in a clear-water state; (2) during the clear-water state, the loss of benthic production was gradually replaced by phytoplankton production, leaving whole-lake production largely unchanged; (3) the responses of lakes to biomanipulation and increased external P loading were both dependent on lake morphometry; and (4) the capacity of periphyton to buffer the effects of increased external P loading and maintain a clear-water state was highly sensitive to relationships between light availability at the sediment surface and the of P release. Our model suggests a mechanism for the persistence of alternative states in shallow macrophyte-free lakes and demonstrates that regime shifts may trigger profound changes in ecosystem structure and function.

  2. Moderate drop in water table increases peatland vulnerability to post-fire regime shift.

    Science.gov (United States)

    Kettridge, N; Turetsky, M R; Sherwood, J H; Thompson, D K; Miller, C A; Benscoter, B W; Flannigan, M D; Wotton, B M; Waddington, J M

    2015-01-27

    Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

  3. Probe-controlled soliton frequency shift in the regime of optical event horizon.

    Science.gov (United States)

    Gu, Jie; Guo, Hairun; Wang, Shaofei; Zeng, Xianglong

    2015-08-24

    In optical analogy of the event horizon, temporal pulse collision and mutual interactions are mainly between an intense solitary wave (soliton) and a dispersive probe wave. In such a regime, here we numerically investigate the probe-controlled soliton frequency shift as well as the soliton self-compression. In particular, in the dispersion landscape with multiple zero dispersion wavelengths, bi-directional soliton spectral tunneling effects is possible. Moreover, we propose a mid-infrared soliton self-compression to the generation of few-cycle ultrashort pulses, in a bulk of quadratic nonlinear crystals in contrast to optical fibers or cubic nonlinear media, which could contribute to the community with a simple and flexible method to experimental implementations.

  4. Beyond the fragmentation threshold hypothesis: regime shifts in biodiversity across fragmented landscapes.

    Directory of Open Access Journals (Sweden)

    Renata Pardini

    Full Text Available Ecological systems are vulnerable to irreversible change when key system properties are pushed over thresholds, resulting in the loss of resilience and the precipitation of a regime shift. Perhaps the most important of such properties in human-modified landscapes is the total amount of remnant native vegetation. In a seminal study Andrén proposed the existence of a fragmentation threshold in the total amount of remnant vegetation, below which landscape-scale connectivity is eroded and local species richness and abundance become dependent on patch size. Despite the fact that species patch-area effects have been a mainstay of conservation science there has yet to be a robust empirical evaluation of this hypothesis. Here we present and test a new conceptual model describing the mechanisms and consequences of biodiversity change in fragmented landscapes, identifying the fragmentation threshold as a first step in a positive feedback mechanism that has the capacity to impair ecological resilience, and drive a regime shift in biodiversity. The model considers that local extinction risk is defined by patch size, and immigration rates by landscape vegetation cover, and that the recovery from local species losses depends upon the landscape species pool. Using a unique dataset on the distribution of non-volant small mammals across replicate landscapes in the Atlantic forest of Brazil, we found strong evidence for our model predictions--that patch-area effects are evident only at intermediate levels of total forest cover, where landscape diversity is still high and opportunities for enhancing biodiversity through local management are greatest. Furthermore, high levels of forest loss can push native biota through an extinction filter, and result in the abrupt, landscape-wide loss of forest-specialist taxa, ecological resilience and management effectiveness. The proposed model links hitherto distinct theoretical approaches within a single framework

  5. Hydrological regime shift in a constructed catchment: Effect of vegetation encroachment on surface runoff

    Science.gov (United States)

    Hinz, C.; Caviedes-Voullieme, D.; Andezhath Mohanan, A.; Brueck, Y.; Zaplata, M.

    2017-12-01

    The Hühnerwasser catchment (Chicken Creek) was constructed to provide discharge for a small stream in the post-mining landscape of Lusatia, Germany. It has an area of 6 ha and quaternary sands with a thickness of 2-4 m were dumped on to a clay liner to prevent deep drainage. After completion of the construction the catchment was left to develop on its own without intervention and has been monitored since 2005. The upper part of the catchment discharges water and sediment into the lower part forming an alluvial fan. Below the alluvial fan is a pond receiving all surface and subsurface water from the upper catchment. After the formation of the drainage network vegetation started growing and surface runoff decreased until the water balance was dominated by evapotranspiration. This regime shift and the rate at which it happened depends on the vegetation encroachment into the rills and the interrill areas. Based on the hypothesis that vegetation will increase surface roughness and infiltration behavior, aerial photos were used to map rills and vegetation within and outside the rills for the last 10 years to obtain a time series of change. Observational evidence clearly shows that vegetation encroaches from the bottom, from the interrill areas as well as from the top. The rills themselves did not change their topology, however, the width of the erosion rills and gully increased at the bottom. For a subcatchment area a high resolution a physical based numerical model of overland flow was developed to explicitly assess the importance of increasing roughness and infiltration capacity for surface runoff. For the purpose of analyzing the effect of rainfall variability a rainfall generator was developed to carry out large sets of simulations. The simulations provide a means to assess how the roughness/infiltration feedback affects the rate of regime shift for a set of parameters that are consistent with the observed hydrological behavior of the drainage network.

  6. Climate and vegetational regime shifts in the late Paleozoic ice age earth.

    Science.gov (United States)

    DiMichele, W A; Montañez, I P; Poulsen, C J; Tabor, N J

    2009-03-01

    The late Paleozoic earth experienced alternation between glacial and non-glacial climates at multiple temporal scales, accompanied by atmospheric CO2 fluctuations and global warming intervals, often attended by significant vegetational changes in equatorial latitudes of Pangaea. We assess the nature of climate-vegetation interaction during two time intervals: middle-late Pennsylvanian transition and Pennsylvanian-Permian transition, each marked by tropical warming and drying. In case study 1, there is a catastrophic intra-biomic reorganization of dominance and diversity in wetland, evergreen vegetation growing under humid climates. This represents a threshold-type change, possibly a regime shift to an alternative stable state. Case study 2 is an inter-biome dominance change in western and central Pangaea from humid wetland and seasonally dry to semi-arid vegetation. Shifts between these vegetation types had been occurring in Euramerican portions of the equatorial region throughout the late middle and late Pennsylvanian, the drier vegetation reaching persistent dominance by Early Permian. The oscillatory transition between humid and seasonally dry vegetation appears to demonstrate a threshold-like behavior but probably not repeated transitions between alternative stable states. Rather, changes in dominance in lowland equatorial regions were driven by long-term, repetitive climatic oscillations, occurring with increasing intensity, within overall shift to seasonal dryness through time. In neither case study are there clear biotic or abiotic warning signs of looming changes in vegetational composition or geographic distribution, nor is it clear that there are specific, absolute values or rates of environmental change in temperature, rainfall distribution and amount, or atmospheric composition, approach to which might indicate proximity to a terrestrial biotic-change threshold.

  7. Non-linear regime shifts in Holocene Asian monsoon variability: potential impacts on cultural change and migratory patterns

    Science.gov (United States)

    Donges, J. F.; Donner, R. V.; Marwan, N.; Breitenbach, S. F. M.; Rehfeld, K.; Kurths, J.

    2015-05-01

    The Asian monsoon system is an important tipping element in Earth's climate with a large impact on human societies in the past and present. In light of the potentially severe impacts of present and future anthropogenic climate change on Asian hydrology, it is vital to understand the forcing mechanisms of past climatic regime shifts in the Asian monsoon domain. Here we use novel recurrence network analysis techniques for detecting episodes with pronounced non-linear changes in Holocene Asian monsoon dynamics recorded in speleothems from caves distributed throughout the major branches of the Asian monsoon system. A newly developed multi-proxy methodology explicitly considers dating uncertainties with the COPRA (COnstructing Proxy Records from Age models) approach and allows for detection of continental-scale regime shifts in the complexity of monsoon dynamics. Several epochs are characterised by non-linear regime shifts in Asian monsoon variability, including the periods around 8.5-7.9, 5.7-5.0, 4.1-3.7, and 3.0-2.4 ka BP. The timing of these regime shifts is consistent with known episodes of Holocene rapid climate change (RCC) and high-latitude Bond events. Additionally, we observe a previously rarely reported non-linear regime shift around 7.3 ka BP, a timing that matches the typical 1.0-1.5 ky return intervals of Bond events. A detailed review of previously suggested links between Holocene climatic changes in the Asian monsoon domain and the archaeological record indicates that, in addition to previously considered longer-term changes in mean monsoon intensity and other climatic parameters, regime shifts in monsoon complexity might have played an important role as drivers of migration, pronounced cultural changes, and the collapse of ancient human societies.

  8. Property rights, institutional regime shifts and the provision of freshwater ecosystem services on the Pongola River floodplain, South Africa

    Directory of Open Access Journals (Sweden)

    Bimo Abraham Nkhata

    2017-03-01

    Full Text Available This paper proposes a property rights perspective to interpret institutional regime shifts in the provision of freshwater ecosystem services. Institutional regime shifts are conceived as persistent changes in the structure and function of a system. Property rights are viewed as an important component of institutional regimes. The paper draws on a case study of flow regulation on the Pongolo Floodplain in South Africa to illustrate the central role of property rights in mediating institutional regime shifts. The case study illustrates that there are many combinations of property rights that underpin institutional regime shifts in the provision of freshwater ecosystem services. It provides useful insights into the consequences of failing to recognize, establish and enforce bundles of rights. A major thrust of the case study is that the nature and context of property rights are important in determining the long-term provision of these services. By examining the configurations of property rights that have governed the Pongola River floodplain over the years, the paper demonstrates the importance of explicitly defining and categorizing the range of rights.

  9. Regime shift by an exotic nitrogen-fixing shrub mediates plant facilitation in primary succession.

    Directory of Open Access Journals (Sweden)

    Adriano Stinca

    Full Text Available Ecosystem invasion by non-native, nitrogen-fixing species is a global phenomenon with serious ecological consequences. However, in the Mediterranean basin few studies addressed the impact of invasion by nitrogen-fixing shrubs on soil quality and hydrological properties at local scale, and the possible effects on succession dynamics and ecosystem invasibility by further species. In this multidisciplinary study we investigated the impact of Genista aetnensis (Biv. DC., an exotic nitrogen-fixing shrub, on the Vesuvius Grand Cone (Southern Italy. Specifically, we tested the hypotheses that the invasion of G. aetnensis has a significant impact on soil quality, soil hydrological regime, local microclimate and plant community structure, and that its impact increases during the plant ontogenetic cycle. We showed that G. aetnensis, in a relatively short time-span (i.e. ~ 40 years, has been able to build-up an island of fertility under its canopy, by accumulating considerable stocks of C, N, and P in the soil, and by also improving the soil hydrological properties. Moreover, G. aetnensis mitigates the daily range of soil temperature, reducing the exposure of coexisting plants to extremely high temperatures and water loss by soil evaporation, particularly during the growing season. Such amelioration of soil quality, coupled with the mitigation of below-canopy microclimatic conditions, has enhanced plant colonization of the barren Grand Cone slopes, by both herbaceous and woody species. These results suggest that the invasion of G. aetnensis could eventually drive to the spread of other, more resource-demanding exotic species, promoting alternative successional trajectories that may dramatically affect the local landscape. Our study is the first record of the invasion of G. aetnensis, an additional example of the regime shifts driven by N-fixing shrubs in Mediterranean region. Further studies are needed to identity specific management practices that can

  10. Kittiwake diets and chick production signal a 2008 regime shift in the Northeast Pacific

    Science.gov (United States)

    Hatch, Scott A.

    2013-01-01

    I examined ~2700 food samples collected from adult and nestling black-legged kittiwakes Rissa tridactyla from 1978 through 2011 on Middleton Island in the Gulf of Alaska. The kittiwake diet was composed chiefly of fish, but invertebrates were taken in appreciable quantities in April and May. Upon spring arrival at the colony, adult kittiwakes foraged regularly at night on vertically migrating mesopelagic prey—lanternfishes (Myctophidae), squids, crustaceans, and polychaetes—a behavior they largely discontinued by egg-laying. During incubation and chick-rearing, food samples contained mostly (~85% by weight) Pacific sand lance Ammodytes hexapterus, capelin Mallotus villosus, Pacific herring Clupea pallasii, sablefish Anopoploma fimbria, krill (Euphausiidae), and juvenile salmon Onchorynchus gorboscha and O. keta. A salient finding over the longitudinal study was the emergence, twice, of capelin as a dominant forage species—once in 2000 to 2003, and again in 2008 through 2011. Kittiwakes responded to capelin availability by producing markedly higher numbers of fledged young. The 2000 to 2003 event corresponded to a previously documented shift to cooler conditions in the NE Pacific, which apparently was relatively limited in magnitude or duration. The more recent transition appears stronger and may be more lasting. I submit that 2008 was an important turning point, marking a substantive reversal of warm conditions that began with the well-documented regime shift of 1977. That interpretation is consistent with the existence of a ~60 yr cycle in ocean and atmospheric conditions in the North Pacific. All else being equal, it predicts the next 20 to 30 yr will be favorable for species such as kittiwakes and Steller sea lions, which seemed to respond negatively to the 1977 to 2007 warm phase of the Pacific Decadal Oscillation.

  11. Trends in shifting cultivation and the REDD mechanism

    DEFF Research Database (Denmark)

    Mertz, Ole

    2009-01-01

    of the transitions taking place. The proposed mechanism for reduced greenhouse gas emissions from deforestation and degradation (REDD) can be both a challenge and opportunity for shifting cultivators. Very limited literature is available on this dilemma, but a few sources point to benefits from ‘compensated...

  12. Atlantic SSTs control regime shifts in forest fire activity of Northern Scandinavia

    Science.gov (United States)

    Drobyshev, Igor; Bergeron, Yves; Vernal, Anne De; Moberg, Anders; Ali, Adam A.; Niklasson, Mats

    2016-03-01

    Understanding the drivers of the boreal forest fire activity is challenging due to the complexity of the interactions driving fire regimes. We analyzed drivers of forest fire activity in Northern Scandinavia (above 60 N) by combining modern and proxy data over the Holocene. The results suggest that the cold climate in northern Scandinavia was generally characterized by dry conditions favourable to periods of regionally increased fire activity. We propose that the cold conditions over the northern North Atlantic, associated with low SSTs, expansion of sea ice cover, and the southward shift in the position of the subpolar gyre, redirect southward the precipitation over Scandinavia, associated with the westerlies. This dynamics strengthens high pressure systems over Scandinavia and results in increased regional fire activity. Our study reveals a previously undocumented teleconnection between large scale climate and ocean dynamics over the North Atlantic and regional boreal forest fire activity in Northern Scandinavia. Consistency of the pattern observed annually through millennium scales suggests that a strong link between Atlantic SST and fire activity on multiple temporal scales over the entire Holocene is relevant for understanding future fire activity across the European boreal zone.

  13. How do copper contamination pulses shape the regime shifts of phytoplankton-zooplankton dynamics?

    Science.gov (United States)

    Camara, B. I.; Yamapi, R.; Mokrani, H.

    2017-07-01

    The presence of pollutants in waters, particularly from heavy metals, is of grave concern worldwide due to its cytotoxicity to organisms. Fish and aquatic organisms are very sensitive to the increasing Cu concentrations in water. Therefore, Cu toxicity partly depends on water quality. To address the effects of impulsive copper contamination of the phytoplankton-zooplankton population dynamics, we've built a model that focuses on the interaction between algae and Daphnia with deterministic and stochastic impulse copper. In fact the Results have shown three types of outcomes depending on copper concentration. In low (4.4 μgL-1) copper concentration, deterministic and stochastic pulses may promote the persistence of Daphnia and algae populations unlike the absence of pulses. Whereas, in high (28 μgL-1) concentration, it accelerates deficiency and toxicity processes, leads to the extinction of all populations and in intermediate concentrations. Deterministic and stochastic pulses may transform population dynamics in complex oscillations. Numerical results show that the system that has been considered has more complex dynamics including bifurcation, period-doubling oscillations and chaos. Depending on minimum copper concentration in the environment, the bifurcation diagram has highlighted the resilience or the regime shifts of the system in occurrence of pulse contamination.

  14. Atlantic SSTs control regime shifts in forest fire activity of Northern Scandinavia

    Science.gov (United States)

    Drobyshev, Igor; Bergeron, Yves; Vernal, Anne de; Moberg, Anders; Ali, Adam A.; Niklasson, Mats

    2016-01-01

    Understanding the drivers of the boreal forest fire activity is challenging due to the complexity of the interactions driving fire regimes. We analyzed drivers of forest fire activity in Northern Scandinavia (above 60 N) by combining modern and proxy data over the Holocene. The results suggest that the cold climate in northern Scandinavia was generally characterized by dry conditions favourable to periods of regionally increased fire activity. We propose that the cold conditions over the northern North Atlantic, associated with low SSTs, expansion of sea ice cover, and the southward shift in the position of the subpolar gyre, redirect southward the precipitation over Scandinavia, associated with the westerlies. This dynamics strengthens high pressure systems over Scandinavia and results in increased regional fire activity. Our study reveals a previously undocumented teleconnection between large scale climate and ocean dynamics over the North Atlantic and regional boreal forest fire activity in Northern Scandinavia. Consistency of the pattern observed annually through millennium scales suggests that a strong link between Atlantic SST and fire activity on multiple temporal scales over the entire Holocene is relevant for understanding future fire activity across the European boreal zone. PMID:26940995

  15. Trends and variability in the hydrological regime of the Mackenzie River Basin

    Science.gov (United States)

    Abdul Aziz, Omar I.; Burn, Donald H.

    2006-03-01

    Trends and variability in the hydrological regime were analyzed for the Mackenzie River Basin in northern Canada. The procedure utilized the Mann-Kendall non-parametric test to detect trends, the Trend Free Pre-Whitening (TFPW) approach for correcting time-series data for autocorrelation and a bootstrap resampling method to account for the cross-correlation structure of the data. A total of 19 hydrological and six meteorological variables were selected for the study. Analysis was conducted on hydrological data from a network of 54 hydrometric stations and meteorological data from a network of 10 stations. The results indicated that several hydrological variables exhibit a greater number of significant trends than are expected to occur by chance. Noteworthy were strong increasing trends over the winter month flows of December to April as well as in the annual minimum flow and weak decreasing trends in the early summer and late fall flows as well as in the annual mean flow. An earlier onset of the spring freshet is noted over the basin. The results are expected to assist water resources managers and policy makers in making better planning decisions in the Mackenzie River Basin.

  16. Regional Distribution Shifts Help Explain Local Changes in Wintering Raptor Abundance: Implications for Interpreting Population Trends

    OpenAIRE

    Paprocki, Neil; Heath, Julie A.; Novak, Stephen J.

    2014-01-01

    Studies of multiple taxa across broad-scales suggest that species distributions are shifting poleward in response to global climate change. Recognizing the influence of distribution shifts on population indices will be an important part of interpreting trends within management units because current practice often assumes that changes in local populations reflect local habitat conditions. However, the individual- and population-level processes that drive distribution shifts may occur across a ...

  17. Labour force participation in Canada: Trends and shifts

    OpenAIRE

    Irene Ip

    1998-01-01

    A key determinant of the potential growth of an economy is the rate at which the labour force increases, which depends both on population growth and on changes in the participation rate. Cyclical factors related to the economic environment can play a significant role in affecting the participation rate, as can structural factors and demographic trends. From the mid-1970s to the end of the 1980s, the participation rate rose almost without interruption to a record high of 67.5 per cent. In cont...

  18. Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic

    Science.gov (United States)

    Bjorndal, Karen A.; Bolten, Alan B.; Chaloupka, Milani; Saba, Vincent S.; Bellini, Cláudio; Marcovaldi, Maria A.G.; Santos, Armando J.B.; Bortolon, Luis Felipe Wurdig; Meylan, Anne B.; Meylan, Peter A.; Gray, Jennifer; Hardy, Robert; Brost, Beth; Bresette, Michael; Gorham, Jonathan C.; Connett, Stephen; Crouchley, Barbara Van Sciver; Dawson, Mike; Hayes, Deborah; Diez, Carlos E.; van Dam, Robert P.; Willis, Sue; Nava, Mabel; Hart, Kristen M.; Cherkiss, Michael S.; Crowder, Andrew; Pollock, Clayton; Hillis-Starr, Zandy; Muñoz Tenería, Fernando A.; Herrera-Pavón, Roberto; Labrada-Martagón, Vanessa; Lorences, Armando; Negrete-Philippe, Ana; Lamont, Margaret M.; Foley, Allen M.; Bailey, Rhonda; Carthy, Raymond R.; Scarpino, Russell; McMichael, Erin; Provancha, Jane A.; Brooks, Annabelle; Jardim, Adriana; López-Mendilaharsu, Milagros; González-Paredes, Daniel; Estrades, Andrés; Fallabrino, Alejandro; Martínez-Souza, Gustavo; Vélez-Rubio, Gabriela M.; Boulon, Ralf H.; Collazo, Jaime; Wershoven, Robert; Hernández, Vicente Guzmán; Stringell, Thomas B.; Sanghera, Amdeep; Richardson, Peter B.; Broderick, Annette C.; Phillips, Quinton; Calosso, Marta C.; Claydon, John A.B.; Metz, Tasha L.; Gordon, Amanda L.; Landry, Andre M.; Shaver, Donna J.; Blumenthal, Janice; Collyer, Lucy; Godley, Brendan J.; McGowan, Andrew; Witt, Matthew J.; Campbell, Cathi L.; Lagueux, Cynthia J.; Bethel, Thomas L.; Kenyon, Lory

    2017-01-01

    Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles – hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta – exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO) – the strongest on record – combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -0.94) and the Multivariate ENSO Index (MEI) for all years (r = 0.74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study

  19. Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic.

    Science.gov (United States)

    Bjorndal, Karen A; Bolten, Alan B; Chaloupka, Milani; Saba, Vincent S; Bellini, Cláudio; Marcovaldi, Maria A G; Santos, Armando J B; Bortolon, Luis Felipe Wurdig; Meylan, Anne B; Meylan, Peter A; Gray, Jennifer; Hardy, Robert; Brost, Beth; Bresette, Michael; Gorham, Jonathan C; Connett, Stephen; Crouchley, Barbara Van Sciver; Dawson, Mike; Hayes, Deborah; Diez, Carlos E; van Dam, Robert P; Willis, Sue; Nava, Mabel; Hart, Kristen M; Cherkiss, Michael S; Crowder, Andrew G; Pollock, Clayton; Hillis-Starr, Zandy; Muñoz Tenería, Fernando A; Herrera-Pavón, Roberto; Labrada-Martagón, Vanessa; Lorences, Armando; Negrete-Philippe, Ana; Lamont, Margaret M; Foley, Allen M; Bailey, Rhonda; Carthy, Raymond R; Scarpino, Russell; McMichael, Erin; Provancha, Jane A; Brooks, Annabelle; Jardim, Adriana; López-Mendilaharsu, Milagros; González-Paredes, Daniel; Estrades, Andrés; Fallabrino, Alejandro; Martínez-Souza, Gustavo; Vélez-Rubio, Gabriela M; Boulon, Ralf H; Collazo, Jaime A; Wershoven, Robert; Guzmán Hernández, Vicente; Stringell, Thomas B; Sanghera, Amdeep; Richardson, Peter B; Broderick, Annette C; Phillips, Quinton; Calosso, Marta; Claydon, John A B; Metz, Tasha L; Gordon, Amanda L; Landry, Andre M; Shaver, Donna J; Blumenthal, Janice; Collyer, Lucy; Godley, Brendan J; McGowan, Andrew; Witt, Matthew J; Campbell, Cathi L; Lagueux, Cynthia J; Bethel, Thomas L; Kenyon, Lory

    2017-11-01

    Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the

  20. Shifting production trends point to more oil from OPEC

    International Nuclear Information System (INIS)

    Ismail, I.A.H.

    1994-01-01

    Oil production from the Organization of Petroleum Exporting Countries and non-OPEC regions has undergone four major phases of change in relation to oil price since 1960. Patterns visible in those phases offer an indication of world-wide production trends in the future. These four phases are described. Overall, demand for oil during 1960--93 has increased from around 20 million b/d in 1960 to as high as 65 million b/d in 1993. The consensus among energy analysts and forecasters is that this demand growth will continue. This will encourage OPEC and non OPEC producers to invest in the oil industry to meet future demand growth. However, since the resource base is larger in OPEC than in non-OPEC areas, and since the cost of developing these resources is lower in OPEC than outside OPEC, the future call on OPEC oil to meet growth in demand will undoubtedly be substantiated as production from the non-OPEC region diminishes or at best stagnates. The paper discusses OPEC production trends, non-OPEC production, natural gas liquids, future production scenarios, and future constraints on production

  1. The Mediterranean Sea regime shift at the end of the 1980s, and intriguing parallelisms with other European basins.

    Science.gov (United States)

    Conversi, Alessandra; Fonda Umani, Serena; Peluso, Tiziana; Molinero, Juan Carlos; Santojanni, Alberto; Edwards, Martin

    2010-05-19

    Regime shifts are abrupt changes encompassing a multitude of physical properties and ecosystem variables, which lead to new regime conditions. Recent investigations focus on the changes in ecosystem diversity and functioning associated to such shifts. Of particular interest, because of the implication on climate drivers, are shifts that occur synchronously in separated basins. In this work we analyze and review long-term records of Mediterranean ecological and hydro-climate variables and find that all point to a synchronous change in the late 1980s. A quantitative synthesis of the literature (including observed oceanic data, models and satellite analyses) shows that these years mark a major change in Mediterranean hydrographic properties, surface circulation, and deep water convection (the Eastern Mediterranean Transient). We provide novel analyses that link local, regional and basin scale hydrological properties with two major indicators of large scale climate, the North Atlantic Oscillation index and the Northern Hemisphere Temperature index, suggesting that the Mediterranean shift is part of a large scale change in the Northern Hemisphere. We provide a simplified scheme of the different effects of climate vs. temperature on pelagic ecosystems. Our results show that the Mediterranean Sea underwent a major change at the end of the 1980s that encompassed atmospheric, hydrological, and ecological systems, for which it can be considered a regime shift. We further provide evidence that the local hydrography is linked to the larger scale, northern hemisphere climate. These results suggest that the shifts that affected the North, Baltic, Black and Mediterranean (this work) Seas at the end of the 1980s, that have been so far only partly associated, are likely linked as part a northern hemisphere change. These findings bear wide implications for the development of climate change scenarios, as synchronous shifts may provide the key for distinguishing local (i.e., basin

  2. The Mediterranean Sea regime shift at the end of the 1980s, and intriguing parallelisms with other European basins.

    Directory of Open Access Journals (Sweden)

    Alessandra Conversi

    Full Text Available BACKGROUND: Regime shifts are abrupt changes encompassing a multitude of physical properties and ecosystem variables, which lead to new regime conditions. Recent investigations focus on the changes in ecosystem diversity and functioning associated to such shifts. Of particular interest, because of the implication on climate drivers, are shifts that occur synchronously in separated basins. PRINCIPAL FINDINGS: In this work we analyze and review long-term records of Mediterranean ecological and hydro-climate variables and find that all point to a synchronous change in the late 1980s. A quantitative synthesis of the literature (including observed oceanic data, models and satellite analyses shows that these years mark a major change in Mediterranean hydrographic properties, surface circulation, and deep water convection (the Eastern Mediterranean Transient. We provide novel analyses that link local, regional and basin scale hydrological properties with two major indicators of large scale climate, the North Atlantic Oscillation index and the Northern Hemisphere Temperature index, suggesting that the Mediterranean shift is part of a large scale change in the Northern Hemisphere. We provide a simplified scheme of the different effects of climate vs. temperature on pelagic ecosystems. CONCLUSIONS: Our results show that the Mediterranean Sea underwent a major change at the end of the 1980s that encompassed atmospheric, hydrological, and ecological systems, for which it can be considered a regime shift. We further provide evidence that the local hydrography is linked to the larger scale, northern hemisphere climate. These results suggest that the shifts that affected the North, Baltic, Black and Mediterranean (this work Seas at the end of the 1980s, that have been so far only partly associated, are likely linked as part a northern hemisphere change. These findings bear wide implications for the development of climate change scenarios, as synchronous shifts

  3. Trends of rainfall regime in Peninsular Malaysia during northeast and southwest monsoons

    Science.gov (United States)

    Chooi Tan, Kok

    2018-04-01

    The trends of rainfall regime in Peninsular Malaysia is mainly affected by the seasonal monsoon. The aim of this study is to investigate the impact of northeast and southwest monsoons on the monthly rainfall patterns over Badenoch Estate, Kedah. In addition, the synoptic maps of wind vector also being developed to identify the wind pattern over Peninsular Malaysia from 2007 – 2016. On the other hand, the archived daily rainfall data is acquired from Malaysian Meteorological Department. The temporal and trends of the monthly and annual rainfall over the study area have been analysed from 2007 to 2016. Overall, the average annual precipitation over the study area from 2007 to 2016 recorded by rain gauge is 2562.35 mm per year.

  4. Extrinsic regime shifts drive abrupt changes in regeneration dynamics at upper treeline in the Rocky Mountains, U.S.A.

    Science.gov (United States)

    Elliott, Grant P

    2012-07-01

    Given the widespread and often dramatic influence of climate change on terrestrial ecosystems, it is increasingly common for abrupt threshold changes to occur, yet explicitly testing for climate and ecological regime shifts is lacking in climatically sensitive upper treeline ecotones. In this study, quantitative evidence based on empirical data is provided to support the key role of extrinsic, climate-induced thresholds in governing the spatial and temporal patterns of tree establishment in these high-elevation environments. Dendroecological techniques were used to reconstruct a 420-year history of regeneration dynamics within upper treeline ecotones along a latitudinal gradient (approximately 44-35 degrees N) in the Rocky Mountains. Correlation analysis was used to assess the possible influence of minimum and maximum temperature indices and cool-season (November-April) precipitation on regional age-structure data. Regime-shift analysis was used to detect thresholds in tree establishment during the entire period of record (1580-2000), temperature variables significantly Correlated with establishment during the 20th century, and cool-season precipitation. Tree establishment was significantly correlated with minimum temperature during the spring (March-May) and cool season. Regime-shift analysis identified an abrupt increase in regional tree establishment in 1950 (1950-1954 age class). Coincident with this period was a shift toward reduced cool-season precipitation. The alignment of these climate conditions apparently triggered an abrupt increase in establishment that was unprecedented during the period of record. Two main findings emerge from this research that underscore the critical role of climate in governing regeneration dynamics within upper treeline ecotones. (1) Regional climate variability is capable of exceeding bioclimatic thresholds, thereby initiating synchronous and abrupt changes in the spatial and temporal patterns of tree establishment at broad

  5. Ecological Regime Shifts in Lake Kälksjön, Sweden, in Response to Abrupt Climate Change Around the 8.2 ka Cooling Event

    DEFF Research Database (Denmark)

    Randsalu-Wendrup, L.; Conley, D.J.; Snowball, I.

    2012-01-01

    . This study demonstrates that it is possible to detect, quantify and test for regime shifts in paleoecological data, and it highlights the need for high sampling resolution and precise chronological control. High-resolution paleoecological reconstructions of ecological regime shifts in response to climate...

  6. Regime shift from phytoplankton to macrophyte dominance in a large river: Top-down versus bottom-up effects

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez, Carles, E-mail: carles.ibanez@irta.cat [IRTA Aquatic Ecosystems, Carretera Poble Nou, Km 5.5, 43540 St. Carles de la Rapita, Catalonia (Spain); Alcaraz, Carles; Caiola, Nuno; Rovira, Albert; Trobajo, Rosa [IRTA Aquatic Ecosystems, Carretera Poble Nou, Km 5.5, 43540 St. Carles de la Rapita, Catalonia (Spain); Alonso, Miguel [United Research Services S.L., Urgell 143, 08036 Barcelona, Catalonia (Spain); Duran, Concha [Confederacion Hidrografica del Ebro, Sagasta 24-26, 50071 Zaragoza, Aragon (Spain); Jimenez, Pere J. [Grup Natura Freixe, Major 56, 43750 Flix, Catalonia (Spain); Munne, Antoni [Agencia Catalana de l' Aigua, Provenca 204-208, 08036 Barcelona, Catalonia (Spain); Prat, Narcis [Departament d' Ecologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona Catalonia (Spain)

    2012-02-01

    The lower Ebro River (Catalonia, Spain) has recently undergone a regime shift from a phytoplankton-dominated to a macrophyte-dominated system. This shift is well known in shallow lakes but apparently it has never been documented in rivers. Two initial hypotheses to explain the collapse of the phytoplankton were considered: a) the diminution of nutrients (bottom-up); b) the filtering effect due to the colonization of the zebra mussel (top-down). Data on water quality, hydrology and biological communities (phytoplankton, macrophytes and zebra mussel) was obtained both from existing data sets and new surveys. Results clearly indicate that the decrease in phosphorus is the main cause of a dramatic decrease in chlorophyll and large increase in water transparency, triggering the subsequent colonization of macrophytes in the river bed. A Generalized Linear Model analysis showed that the decrease in dissolved phosphorus had a relative importance 14 times higher than the increase in zebra mussel density to explain the variation of total chlorophyll. We suggest that the described changes in the lower Ebro River can be considered a novel ecosystem shift. This shift is triggering remarkable changes in the biological communities beyond the decrease of phytoplankton and the proliferation of macrophytes, such as massive colonization of Simulidae (black fly) and other changes in the benthic invertebrate communities that are currently investigated. - Highlights: Black-Right-Pointing-Pointer We show a regime shift in a large river from phytoplankton to macrophyte dominance. Black-Right-Pointing-Pointer Two main hypotheses are considered: nutrient decrease and zebra mussel grazing. Black-Right-Pointing-Pointer Phosphorus depletion is found to be the main cause of the phytoplankton decline. Black-Right-Pointing-Pointer We conclude that oligotrophication triggered the colonization of macrophytes. Black-Right-Pointing-Pointer This new regime shift in a river is similar to that described

  7. Regime shift from phytoplankton to macrophyte dominance in a large river: Top-down versus bottom-up effects

    International Nuclear Information System (INIS)

    Ibáñez, Carles; Alcaraz, Carles; Caiola, Nuno; Rovira, Albert; Trobajo, Rosa; Alonso, Miguel; Duran, Concha; Jiménez, Pere J.; Munné, Antoni; Prat, Narcís

    2012-01-01

    The lower Ebro River (Catalonia, Spain) has recently undergone a regime shift from a phytoplankton-dominated to a macrophyte-dominated system. This shift is well known in shallow lakes but apparently it has never been documented in rivers. Two initial hypotheses to explain the collapse of the phytoplankton were considered: a) the diminution of nutrients (bottom-up); b) the filtering effect due to the colonization of the zebra mussel (top-down). Data on water quality, hydrology and biological communities (phytoplankton, macrophytes and zebra mussel) was obtained both from existing data sets and new surveys. Results clearly indicate that the decrease in phosphorus is the main cause of a dramatic decrease in chlorophyll and large increase in water transparency, triggering the subsequent colonization of macrophytes in the river bed. A Generalized Linear Model analysis showed that the decrease in dissolved phosphorus had a relative importance 14 times higher than the increase in zebra mussel density to explain the variation of total chlorophyll. We suggest that the described changes in the lower Ebro River can be considered a novel ecosystem shift. This shift is triggering remarkable changes in the biological communities beyond the decrease of phytoplankton and the proliferation of macrophytes, such as massive colonization of Simulidae (black fly) and other changes in the benthic invertebrate communities that are currently investigated. - Highlights: ► We show a regime shift in a large river from phytoplankton to macrophyte dominance. ► Two main hypotheses are considered: nutrient decrease and zebra mussel grazing. ► Phosphorus depletion is found to be the main cause of the phytoplankton decline. ► We conclude that oligotrophication triggered the colonization of macrophytes. ► This new regime shift in a river is similar to that described in shallow lakes.

  8. The effects of crude oil shocks on stock market shifts behaviour A regime switching approach

    Energy Technology Data Exchange (ETDEWEB)

    Aloui, Chaker; Jammazi, Rania [International Finance Group-Tunisia, Faculty of Management and Economic Sciences of Tunis, Boulevard du 7 novembre, El Manar University, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia)

    2009-09-15

    In this paper we develop a two regime Markov-switching EGARCH model introduced by Henry [Henry, O., 2009. Regime switching in the relationship between equity returns and short-term interest rates. Journal of Banking and Finance 33, 405-414.] to examine the relationship between crude oil shocks and stock markets. An application to stock markets of UK, France and Japan over the sample period January 1989 to December 2007 illustrates plausible results. We detect two episodes of series behaviour one relative to low mean/high variance regime and the other to high mean/low variance regime. Furthermore, there is evidence that common recessions coincide with the low mean/high variance regime. In addition, we allow both real stock returns and probability of transitions from one regime to another to depend on the net oil price increase variable. The findings show that rises in oil price has a significant role in determining both the volatility of stock returns and the probability of transition across regimes. (author)

  9. The effects of crude oil shocks on stock market shifts behaviour A regime switching approach

    International Nuclear Information System (INIS)

    Aloui, Chaker; Jammazi, Rania

    2009-01-01

    In this paper we develop a two regime Markov-switching EGARCH model introduced by Henry [Henry, O., 2009. Regime switching in the relationship between equity returns and short-term interest rates. Journal of Banking and Finance 33, 405-414.] to examine the relationship between crude oil shocks and stock markets. An application to stock markets of UK, France and Japan over the sample period January 1989 to December 2007 illustrates plausible results. We detect two episodes of series behaviour one relative to low mean/high variance regime and the other to high mean/low variance regime. Furthermore, there is evidence that common recessions coincide with the low mean/high variance regime. In addition, we allow both real stock returns and probability of transitions from one regime to another to depend on the net oil price increase variable. The findings show that rises in oil price has a significant role in determining both the volatility of stock returns and the probability of transition across regimes. (author)

  10. Regime shifts in mean-variance efficient frontiers: some international evidence

    OpenAIRE

    Massimo Guidolin; Federica Ria

    2010-01-01

    Regime switching models have been assuming a central role in financial applications because of their well-known ability to capture the presence of rich non-linear patterns in the joint distribution of asset returns. This paper examines how the presence of regimes in means, variances, and correlations of asset returns translates into explicit dynamics of the Markowitz mean-variance frontier. In particular, the paper shows both theoretically and through an application to international equity po...

  11. Investigating Snow Cover and Hydrometeorological Trends in Contrasting Hydrological Regimes of the Upper Indus Basin

    Directory of Open Access Journals (Sweden)

    Iqra Atif

    2018-04-01

    Full Text Available The Upper Indus basin (UIB is characterized by contrasting hydrometeorological behaviors; therefore, it has become pertinent to understand hydrometeorological trends at the sub-watershed level. Many studies have investigated the snow cover and hydrometeorological modeling at basin level but none have reported the spatial variability of trends and their magnitude at a sub-basin level. This study was conducted to analyze the trends in the contrasting hydrological regimes of the snow and glacier-fed river catchments of the Hunza and Astore sub-basins of the UIB. Mann-Kendall and Sen’s slope methods were used to study the main trends and their magnitude using MODIS snow cover information (2001–2015 and hydrometeorological data. The results showed that in the Hunza basin, the river discharge and temperature were significantly (p ≤ 0.05 decreased with a Sen’s slope value of −2.541 m3·s−1·year−1 and −0.034 °C·year−1, respectively, while precipitation data showed a non-significant (p ≥ 0.05 increasing trend with a Sen’s slope value of 0.023 mm·year−1. In the Astore basin, the river discharge and precipitation are increasing significantly (p ≤ 0.05 with a Sen’s slope value of 1.039 m3·s−1·year−1 and 0.192 mm·year−1, respectively. The snow cover analysis results suggest that the Western Himalayas (the Astore basin had a stable trend with a Sen’s slope of 0.07% year−1 and the Central Karakoram region (the Hunza River basin shows a slightly increasing trend with a Sen’s slope of 0.394% year−1. Based on the results of this study it can be concluded that since both sub-basins are influenced by different climatological systems (monsoon and westerly, the results of those studies that treat the Upper Indus basin as one unit in hydrometeorological modeling should be used with caution. Furthermore, it is suggested that similar studies at the sub-basin level of the UIB will help in a better understanding of the

  12. International Petroleum Fiscal Regimes: Trends in Tax-Royalty Worldwide and in Romania

    Directory of Open Access Journals (Sweden)

    MARIANA PAPATULICĂ

    2014-05-01

    Full Text Available “Resource nationalism” is a cyclical phenomenon whereby governments assert varying degrees of control over natural resources located within their territories, in an attempt to maximise revenue generation from their national resources. Resource nationalism often depends on the price of hydrocarbons and the ability of national governments to extract them. International oil companies are attractive partners for the development of concessions as they have advanced extractive technology, superior project management skills, flexible logistical chains and access to capital from global financial markets. However, these advantages will erode as National Oil Companies (NOCs improve their expertise over the mid- to long-term and new forms of resource nationalism may restrict their room for manoeuvre.The recent trends in most of oil producing countries’ policies are focusing on highly increasing the fiscal levies imposed to resources exploited under the concession agreements and also on imposing minimum labor taxes. At the end of 2014, The Romanian Government will have to reappraise the fiscal systems for the companies operating in the national oil and gas upstream sector, because the 10-year "freezing" of royalties on oil and gas, at a very low level compared with other producing countries will come to an end. This article tries to present the trends in the international petroleum fiscal regimes worldwide, to make a comparative analysis between Romania and other countries from this point of view and finally to make some recommendations as regards the main guidelines that the negociators could follow in order to obtain better conditions for the new fiscal regime and implicitly a better turning into account of our natural resources to the benefit of the consumers.

  13. Tracking Equilibrium and Nonequilibrium Shifts in Data with TREND.

    Science.gov (United States)

    Xu, Jia; Van Doren, Steven R

    2017-01-24

    Principal component analysis (PCA) discovers patterns in multivariate data that include spectra, microscopy, and other biophysical measurements. Direct application of PCA to crowded spectra, images, and movies (without selecting peaks or features) was shown recently to identify their equilibrium or temporal changes. To enable the community to utilize these capabilities with a wide range of measurements, we have developed multiplatform software named TREND to Track Equilibrium and Nonequilibrium population shifts among two-dimensional Data frames. TREND can also carry this out by independent component analysis. We highlight a few examples of finding concurrent processes. TREND extracts dual phases of binding to two sites directly from the NMR spectra of the titrations. In a cardiac movie from magnetic resonance imaging, TREND resolves principal components (PCs) representing breathing and the cardiac cycle. TREND can also reconstruct the series of measurements from selected PCs, as illustrated for a biphasic, NMR-detected titration and the cardiac MRI movie. Fidelity of reconstruction of series of NMR spectra or images requires more PCs than needed to plot the largest population shifts. TREND reads spectra from many spectroscopies in the most common formats (JCAMP-DX and NMR) and multiple movie formats. The TREND package thus provides convenient tools to resolve the processes recorded by diverse biophysical methods. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  14. Sector-based political analysis of energy transition: Green shift in the forest policy regime in France

    International Nuclear Information System (INIS)

    Sergent, Arnaud

    2014-01-01

    This article examines energy transition political process from a sector-based approach, through the analysis of recent shift in the French forest policy regime. We demonstrate that, since 2007, energy transition policies have led to a harvesting turn within the French forest policy framework, meaning that priority is given to wood mobilisation, mainly for biomass uses. In addition, our findings suggest that the political authority wielded by the state over forest policy has shifted from forest administrative services to energy agencies and local authorities. Finally, we show that, although implementation of the harvesting turn is a cause of sectoral and inter-sectoral tensions, energy transition challenge also contributes to a process of (re)institutionalisation of mediation relationships among forestry stakeholders and wood-based industries representatives. The article concludes by arguing that sectors should retain relevant institutional frameworks for actors when choosing political arrangements required for implementing energy transition policy. - Highlights: • Implementing energy transition policy potentially challenges sector-based politics. • We propose a policy regime framework and socio-political investigations. • We analyse the political impact of energy transition policy on French forest sector. • Shifts occur in sectoral policy framework, authority, and mediation relationships

  15. An empirical model of the Baltic Sea reveals the importance of social dynamics for ecological regime shifts.

    Science.gov (United States)

    Lade, Steven J; Niiranen, Susa; Hentati-Sundberg, Jonas; Blenckner, Thorsten; Boonstra, Wiebren J; Orach, Kirill; Quaas, Martin F; Österblom, Henrik; Schlüter, Maja

    2015-09-01

    Regime shifts triggered by human activities and environmental changes have led to significant ecological and socioeconomic consequences in marine and terrestrial ecosystems worldwide. Ecological processes and feedbacks associated with regime shifts have received considerable attention, but human individual and collective behavior is rarely treated as an integrated component of such shifts. Here, we used generalized modeling to develop a coupled social-ecological model that integrated rich social and ecological data to investigate the role of social dynamics in the 1980s Baltic Sea cod boom and collapse. We showed that psychological, economic, and regulatory aspects of fisher decision making, in addition to ecological interactions, contributed both to the temporary persistence of the cod boom and to its subsequent collapse. These features of the social-ecological system also would have limited the effectiveness of stronger fishery regulations. Our results provide quantitative, empirical evidence that incorporating social dynamics into models of natural resources is critical for understanding how resources can be managed sustainably. We also show that generalized modeling, which is well-suited to collaborative model development and does not require detailed specification of causal relationships between system variables, can help tackle the complexities involved in creating and analyzing social-ecological models.

  16. Hydrological regulation drives regime shifts: evidence from paleolimnology and ecosystem modeling of a large shallow Chinese lake.

    Science.gov (United States)

    Kong, Xiangzhen; He, Qishuang; Yang, Bin; He, Wei; Xu, Fuliu; Janssen, Annette B G; Kuiper, Jan J; van Gerven, Luuk P A; Qin, Ning; Jiang, Yujiao; Liu, Wenxiu; Yang, Chen; Bai, Zelin; Zhang, Min; Kong, Fanxiang; Janse, Jan H; Mooij, Wolf M

    2017-02-01

    Quantitative evidence of sudden shifts in ecological structure and function in large shallow lakes is rare, even though they provide essential benefits to society. Such 'regime shifts' can be driven by human activities which degrade ecological stability including water level control (WLC) and nutrient loading. Interactions between WLC and nutrient loading on the long-term dynamics of shallow lake ecosystems are, however, often overlooked and largely underestimated, which has hampered the effectiveness of lake management. Here, we focus on a large shallow lake (Lake Chaohu) located in one of the most densely populated areas in China, the lower Yangtze River floodplain, which has undergone both WLC and increasing nutrient loading over the last several decades. We applied a novel methodology that combines consistent evidence from both paleolimnological records and ecosystem modeling to overcome the hurdle of data insufficiency and to unravel the drivers and underlying mechanisms in ecosystem dynamics. We identified the occurrence of two regime shifts: one in 1963, characterized by the abrupt disappearance of submerged vegetation, and another around 1980, with strong algal blooms being observed thereafter. Using model scenarios, we further disentangled the roles of WLC and nutrient loading, showing that the 1963 shift was predominantly triggered by WLC, whereas the shift ca. 1980 was attributed to aggravated nutrient loading. Our analysis also shows interactions between these two stressors. Compared to the dynamics driven by nutrient loading alone, WLC reduced the critical P loading and resulted in earlier disappearance of submerged vegetation and emergence of algal blooms by approximately 26 and 10 years, respectively. Overall, our study reveals the significant role of hydrological regulation in driving shallow lake ecosystem dynamics, and it highlights the urgency of using multi-objective management criteria that includes ecological sustainability perspectives when

  17. Trends in low-temperature water–gas shift reactivity on transition metals

    DEFF Research Database (Denmark)

    Schumacher, Nana Maria Pii; Boisen, Astrid; Dahl, Søren

    2005-01-01

    Low-temperature water–gas shift reactivity trends on transition metals were investigated with the use of a microkinetic model based on a redox mechanism. It is established that the adsorption energies for carbon monoxide and oxygen can describe to a large extent changes in the remaining activation...

  18. The long-run forecasting of energy prices using the model of shifting trend

    International Nuclear Information System (INIS)

    Radchenko, Stanislav

    2005-01-01

    Developing models for accurate long-term energy price forecasting is an important problem because these forecasts should be useful in determining both supply and demand of energy. On the supply side, long-term forecasts determine investment decisions of energy-related companies. On the demand side, investments in physical capital and durable goods depend on price forecasts of a particular energy type. Forecasting long-run rend movements in energy prices is very important on the macroeconomic level for several developing countries because energy prices have large impacts on their real output, the balance of payments, fiscal policy, etc. Pindyck (1999) argues that the dynamics of real energy prices is mean-reverting to trend lines with slopes and levels that are shifting unpredictably over time. The hypothesis of shifting long-term trend lines was statistically tested by Benard et al. (2004). The authors find statistically significant instabilities for coal and natural gas prices. I continue the research of energy prices in the framework of continuously shifting levels and slopes of trend lines started by Pindyck (1999). The examined model offers both parsimonious approach and perspective on the developments in energy markets. Using the model of depletable resource production, Pindyck (1999) argued that the forecast of energy prices in the model is based on the long-run total marginal cost. Because the model of a shifting trend is based on the competitive behavior, one may examine deviations of oil producers from the competitive behavior by studying the difference between actual prices and long-term forecasts. To construct the long-run forecasts (10-year-ahead and 15-year-ahead) of energy prices, I modify the univariate shifting trends model of Pindyck (1999). I relax some assumptions on model parameters, the assumption of white noise error term, and propose a new Bayesian approach utilizing a Gibbs sampling algorithm to estimate the model with autocorrelation. To

  19. The altered ecology of Lake Christina: A record of regime shifts, land-use change, and management from a temperate shallow lake

    International Nuclear Information System (INIS)

    Theissen, Kevin M.; Hobbs, William O.; Hobbs, Joy M. Ramstack; Zimmer, Kyle D.; Domine, Leah M.; Cotner, James B.; Sugita, Shinya

    2012-01-01

    We collected two sediment cores and modern submerged aquatic plants and phytoplankton from two sub-basins of Lake Christina, a large shallow lake in west-central Minnesota, and used stable isotopic and elemental proxies from sedimentary organic matter to explore questions about the pre- and post-settlement ecology of the lake. The two morphologically distinct sub-basins vary in their sensitivities to internal and external perturbations offering different paleoecological information. The record from the shallower and much larger western sub-basin reflects its strong response to internal processes, while the smaller and deeper eastern sub-basin record primarily reflects external processes including important post-settlement land-use changes in the area. A significant increase in organic carbon accumulation (3–4 times pre-settlement rates) and long-term trends in δ 13 C, organic carbon to nitrogen ratios (C/N), and biogenic silica concentrations shows that primary production has increased and the lake has become increasingly phytoplankton-dominated in the post-settlement period. Significant shifts in δ 15 N values reflect land-clearing and agricultural practices in the region and support the idea that nutrient inputs have played an important role in triggering changes in the trophic status of the lake. Our examination of hydroclimatic data for the region over the last century suggests that natural forcings on lake ecology have diminished in their importance as human management of the lake increased in the mid-1900s. In the last 50 years, three chemical biomanipulations have temporarily shifted the lake from the turbid, algal-dominated condition into a desired clear water regime. Two of our proxies (δ 13 C and BSi) measured from the higher resolution eastern basin record responded significantly to these known regime shifts. -- Highlights: ► We explore the sediment geochemistry from Lake Christina's two distinct sub-basins. ► Our geochemical data show

  20. Precipitation Regime Shift Enhanced the Rain Pulse Effect on Soil Respiration in a Semi-Arid Steppe

    Science.gov (United States)

    Yan, Liming; Chen, Shiping; Xia, Jianyang; Luo, Yiqi

    2014-01-01

    The effect of resource pulses, such as rainfall events, on soil respiration plays an important role in controlling grassland carbon balance, but how shifts in long-term precipitation regime regulate rain pulse effect on soil respiration is still unclear. We first quantified the influence of rainfall event on soil respiration based on a two-year (2006 and 2009) continuously measured soil respiration data set in a temperate steppe in northern China. In 2006 and 2009, soil carbon release induced by rainfall events contributed about 44.5% (83.3 g C m−2) and 39.6% (61.7 g C m−2) to the growing-season total soil respiration, respectively. The pulse effect of rainfall event on soil respiration can be accurately predicted by a water status index (WSI), which is the product of rainfall event size and the ratio between antecedent soil temperature to moisture at the depth of 10 cm (r 2 = 0.92, Psoil temperature/moisture ratio which is usually associated with longer dry spells. We then analyzed a long-term (1953–2009) precipitation record in the experimental area. We found both the extreme heavy rainfall events (>40 mm per event) and the long dry-spells (>5 days) during the growing seasons increased from 1953–2009. It suggests the shift in precipitation regime has increased the contribution of rain pulse effect to growing-season total soil respiration in this region. These findings highlight the importance of incorporating precipitation regime shift and its impacts on the rain pulse effect into the future predictions of grassland carbon cycle under climate change. PMID:25093573

  1. Atlantic SSTs control regime shifts in forest fire activity of Northern Scandinavia

    OpenAIRE

    Drobyshev, Igor; Bergeron, Yves; Vernal, Anne de; Moberg, Anders; Ali, Adam A.; Niklasson, Mats

    2016-01-01

    Understanding the drivers of the boreal forest fire activity is challenging due to the complexity of the interactions driving fire regimes. We analyzed drivers of forest fire activity in Northern Scandinavia (above 60 N) by combining modern and proxy data over the Holocene. The results suggest that the cold climate in northern Scandinavia was generally characterized by dry conditions favourable to periods of regionally increased fire activity. We propose that the cold conditions over the nort...

  2. Regional Distribution Shifts Help Explain Local Changes in Wintering Raptor Abundance: Implications for Interpreting Population Trends

    Science.gov (United States)

    Paprocki, Neil; Heath, Julie A.; Novak, Stephen J.

    2014-01-01

    Studies of multiple taxa across broad-scales suggest that species distributions are shifting poleward in response to global climate change. Recognizing the influence of distribution shifts on population indices will be an important part of interpreting trends within management units because current practice often assumes that changes in local populations reflect local habitat conditions. However, the individual- and population-level processes that drive distribution shifts may occur across a large, regional scale and have little to do with the habitats within the management unit. We examined the latitudinal center of abundance for the winter distributions of six western North America raptor species using Christmas Bird Counts from 1975–2011. Also, we considered whether population indices within western North America Bird Conservation Regions (BCRs) were explained by distribution shifts. All six raptors had significant poleward shifts in their wintering distributions over time. Rough-legged Hawks (Buteo lagopus) and Golden Eagles (Aquila chrysaetos) showed the fastest rate of change, with 8.41 km yr−1 and 7.74 km yr−1 shifts, respectively. Raptors may be particularly responsive to warming winters because of variable migration tendencies, intraspecific competition for nesting sites that drives males to winter farther north, or both. Overall, 40% of BCR population trend models were improved by incorporating information about wintering distributions; however, support for the effect of distribution on BCR indices varied by species with Rough-legged Hawks showing the most evidence. These results emphasize the importance of understanding how regional distribution shifts influence local-scale population indices. If global climate change is altering distribution patterns, then trends within some management units may not reflect changes in local habitat conditions. The methods used to monitor and manage bird populations within local BCRs will fundamentally change as

  3. Regional distribution shifts help explain local changes in wintering raptor abundance: implications for interpreting population trends.

    Directory of Open Access Journals (Sweden)

    Neil Paprocki

    Full Text Available Studies of multiple taxa across broad-scales suggest that species distributions are shifting poleward in response to global climate change. Recognizing the influence of distribution shifts on population indices will be an important part of interpreting trends within management units because current practice often assumes that changes in local populations reflect local habitat conditions. However, the individual- and population-level processes that drive distribution shifts may occur across a large, regional scale and have little to do with the habitats within the management unit. We examined the latitudinal center of abundance for the winter distributions of six western North America raptor species using Christmas Bird Counts from 1975-2011. Also, we considered whether population indices within western North America Bird Conservation Regions (BCRs were explained by distribution shifts. All six raptors had significant poleward shifts in their wintering distributions over time. Rough-legged Hawks (Buteo lagopus and Golden Eagles (Aquila chrysaetos showed the fastest rate of change, with 8.41 km yr(-1 and 7.74 km yr(-1 shifts, respectively. Raptors may be particularly responsive to warming winters because of variable migration tendencies, intraspecific competition for nesting sites that drives males to winter farther north, or both. Overall, 40% of BCR population trend models were improved by incorporating information about wintering distributions; however, support for the effect of distribution on BCR indices varied by species with Rough-legged Hawks showing the most evidence. These results emphasize the importance of understanding how regional distribution shifts influence local-scale population indices. If global climate change is altering distribution patterns, then trends within some management units may not reflect changes in local habitat conditions. The methods used to monitor and manage bird populations within local BCRs will fundamentally

  4. Review and meta-analysis of trends in precipitation regime in Italy

    Science.gov (United States)

    Caporali, Enrica; Chiarello, Valentina; Defina, Ilaria; Fatichi, Simone

    2017-04-01

    Research to detect changes in climatic variables has become a topic of particular interest to observe signals of climate change as well as to understand drivers of modifications in water resources availability and suggest management adaptations. We specifically focus on Italy, outlining the "state of the art" of the Italian precipitation regime through a review of 46 published studies on rainfall trend analyses. The aim is to combine a large body of knowledge in a single review and to explain the main patterns of rainfall changes occurred in the last decades. The review results are analyzed for the entire Italian peninsula and separately for three macro areas: North, Central and South&Islands. The attention is focused on three indexes at the annual and seasonal scale: mean Total Precipitation (TP), number of Wet Days (WDs) and Precipitation Intensity (PI). Two other aspects are briefly investigated: drought and extreme rainfall events. Different geographic areas, time series length and number of stations, are taken into account using a "weight factor Fi". Subsequently, for each index, findings in terms of increasing or decreasing trends are collected into five principal categories: Negative (N), Negative Significant (NS), Positive (P), Positive Significant (PS), and No Trend (NT). Overall, there is an agreement about the tendency of the WDs that are decreasing on the whole Italy, with some discrepancies regarding the spring and the summer seasons. This is substantially in agreement with the tendency of the TP, especially at annual scale where the presence of a decreasing trend is detected. An opposite behavior is detected for PI, which increases both on an annual and on a seasonal basis. It is worth to point out that PI is analyzed just in few studies and it is strongly influenced on the classification in precipitation intensity intervals. A general finding is that signal to noise ratio on precipitation metrics is quite low, which hampers a clear definition of

  5. Regime shift in fertilizer commodities indicates more turbulence ahead for food security.

    Directory of Open Access Journals (Sweden)

    James J Elser

    Full Text Available Recent human population increase has been enabled by a massive expansion of global agricultural production. A key component of this "Green Revolution" has been application of inorganic fertilizers to produce and maintain high crop yields. However, the long-term sustainability of these practices is unclear given the eutrophying effects of fertilizer runoff as well as the reliance of fertilizer production on finite non-renewable resources such as mined phosphate- and potassium-bearing rocks. Indeed, recent volatility in food and agricultural commodity prices, especially phosphate fertilizer, has raised concerns about emerging constraints on fertilizer production with consequences for its affordability in the developing world. We examined 30 years of monthly prices of fertilizer commodities (phosphate rock, urea, and potassium for comparison with three food commodities (maize, wheat, and rice and three non-agricultural commodities (gold, nickel, and petroleum. Here we show that all commodity prices, except gold, had significant change points between 2007-2009, but the fertilizer commodities, and especially phosphate rock, showed multiple symptoms of nonlinear critical transitions. In contrast to fertilizers and to rice, maize and wheat prices did not show significant signs of nonlinear dynamics. From these results we infer a recent emergence of a scarcity price in global fertilizer markets, a result signaling a new high price regime for these essential agricultural inputs. Such a regime will challenge on-going efforts to establish global food security but may also prompt fertilizer use practices and nutrient recovery strategies that reduce eutrophication.

  6. Resilience of the Nexus of Competitive Water Consumption between Human Society and Environment Development: Regime Shifts and Early Warning Signals

    Science.gov (United States)

    Li, Z.; Liu, P.; Feng, M.; Zhang, J.

    2017-12-01

    Based on the modeling of the water supply, power generation and environment (WPE) nexus by Feng et al. (2016), a refined theoretical model of competitive water consumption between human society and environment has been presented in this study, examining the role of technology advancement and social environmental awareness growth-induced pollution mitigation to the environment as a mechanism for the establishment and maintenance of the coexistence of both higher social water consumption and improved environment condition. By coupling environmental and social dynamics, both of which are represented by water consumption quantity, this study shows the possibility of sustainable situation of the social-environmental system when the benefit of technology offsets the side effect (pollution) of social development to the environment. Additionally, regime shifts could be triggered by gradually increased pollution rate, climate change-induced natural resources reduction and breakdown of the social environmental awareness. Therefore, in order to foresee the pending abrupt regime shifts of the system, early warning signals, including increasing variance and autocorrelation, have been examined when the system is undergoing stochastic disturbance. ADDIN EN.REFLIST Feng, M. et al., 2016. Modeling the nexus across water supply, power generation and environment systems using the system dynamics approach: Hehuang Region, China. J. Hydrol., 543: 344-359.

  7. Regime shifts and ecological catastrophes in a model of plankton-oxygen dynamics under the climate change.

    Science.gov (United States)

    Petrovskii, Sergei; Sekerci, Yadigar; Venturino, Ezio

    2017-07-07

    It is estimated that more than a half of the total atmospheric oxygen is produced in the oceans due to the photosynthetic activity of phytoplankton. Any significant decrease in the net oxygen production by phytoplankton is therefore likely to result in the depletion of atmospheric oxygen and in a global mass mortality of animals and humans. In its turn, the rate of oxygen production is known to depend on water temperature and hence can be affected by the global warming. We address this problem theoretically by considering a model of a coupled plankton-oxygen dynamics where the rate of oxygen production slowly changes with time to account for the ocean warming. We show that, when the temperature rises sufficiently high, a regime shift happens: the sustainable oxygen production becomes impossible and the system's dynamics leads to fast oxygen depletion and plankton extinction. We also consider a scenario when, after a certain period of increase, the temperature is set on a new higher yet apparently safe value, i.e. before the oxygen depletion disaster happens. We show that in this case the system dynamics may exhibit a long-term quasi-sustainable dynamics that can still result in an ecological disaster (oxygen depletion and mass extinctions) but only after a considerable period of time. Finally, we discuss the early warning signals of the approaching regime shift resulting in the disaster. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Persistent millennial-scale shifts in moisture regimes in western Canada during the past six millennia

    Science.gov (United States)

    Cumming, Brian F.; Laird, Kathleen R.; Bennett, Joseph R.; Smol, John P.; Salomon, Anne K.

    2002-01-01

    Inferences of past climatic conditions from a sedimentary record from Big Lake, British Columbia, Canada, over the past 5,500 years show strong millennial-scale patterns, which oscillate between periods of wet and drier climatic conditions. Higher frequency decadal- to centennial-scale fluctuations also occur within the dominant millennial-scale patterns. These changes in climatic conditions are based on estimates of changes in lake depth and salinity inferred from diatom assemblages in a well dated sediment core. After periods of relative stability, abrupt shifts in diatom assemblages and inferred climatic conditions occur approximately every 1,220 years. The correspondence of these shifts to millennial-scale variations in records of glacial expansion/recession and ice-rafting events in the Atlantic suggest that abrupt millennial-scale shifts are important to understanding climatic variability in North America during the mid- to late Holocene. Unfortunately, the spatial patterns and mechanisms behind these large and abrupt swings are poorly understood. Similar abrupt and prolonged changes in climatic conditions today could pose major societal challenges for many regions. PMID:12461174

  9. Regime shifts and panarchies in regional scale social-ecological water systems

    Directory of Open Access Journals (Sweden)

    Lance Gunderson

    2017-03-01

    Full Text Available In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a development and stabilization, (b cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3 periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change.

  10. Regime shifts and panarchies in regional scale social-ecological water systems

    Science.gov (United States)

    Gunderson, Lance; Cosens, Barbara; Chaffin, Brian C.; Arnold, Craig Anthony (Tony); Fremier, Alexander K.; Garmestani, Ahjond S.; Kundis Craig, Robin; Gosnell, Hannah; Birge, Hannah E.; Allen, Craig R.; Benson, Melinda H.; Morrison, Ryan R.; Stone, Mark; Hamm, Joseph A.; Nemec, Kristine T.; Schlager, Edella; Llewellyn, Dagmar

    2017-01-01

    In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change.

  11. Resource manager information needs regarding hydrologic regime shifts for the North Pacific Landscape Conservation

    Science.gov (United States)

    Woodward, Andrea; Jenni, Karen

    2014-01-01

    Landscape Conservation Cooperatives (LCCs) are a network of 22 public-private partnerships, defined by ecoregion, that share and provide science to ensure the sustainability of land, water, wildlife, and cultural resources in North America. LCCs were established by the U.S. Department of the Interior (DOI) in recognition of the fact that response to climate change must be coordinated on a landscape-level basis because important resources, ecosystem processes, and resource management challenges extend beyond most of the boundaries considered in current natural resource management. The North Pacific LCC (NPLCC) covers the range of the Pacific coastal temperate rainforest, including an area of 528,360 km2 spanning 22 degrees of latitude from the Kenai Peninsula, Alaska, to Bodega Bay, California. The coverage area includes parts of four States, two Canadian provinces, and more than 100 Tribes and First Nation language groups. It extends from alpine areas at the crest of coastal mountains across subalpine, montane, and lowland forests to the nearshore marine environment. This wide range of latitudes and elevation zones; terrestrial, freshwater, and marine habitats; and complex jurisdictional boundaries hosts a diversity of natural resources and their corresponding management issues are equally diverse. As evidenced by the Science and Traditional Ecological Knowledge (S-TEK) Strategy guiding principles, identifying and responding to the needs of resource managers is key to the success of the NPLCC. To help achieve this goal of the NPLCC, the U.S. Geological Survey (USGS) has organized several workshops with resource managers and resource scientists to identify management information needs relevant to the priority topics identified in the S-TEK Strategy. Here, we detail the results from a first workshop to address the effects of changes in hydrologic regime on rivers, streams, and riparian corridors. The workshop focused on a subset of the full NPLCC geography and was

  12. Trends of perfluorochemicals in Greenland ringed seals and polar bears: indications of shifts to decreasing trends.

    Science.gov (United States)

    Rigét, Frank; Bossi, Rossana; Sonne, Christian; Vorkamp, Katrin; Dietz, Rune

    2013-11-01

    Time-series of perfluorinated alkylated substances (PFASs) in East Greenland polar bears and East and West Greenland ringed seals were updated in order to deduce whether a response to the major reduction in perfluoroalkyl production in the early 2000s had occurred. Previous studies had documented an exponential increase of perfluorooctane sulphonate (PFOS) in liver tissue from both species. In the present study, PFOS was still the far most dominant compound constituting 92% (West Greenland ringed seals), 88% (East Greenland ringed seals) and 85% (East Greenland polar bears). The PFOS concentrations increased up to 2006 with doubling times of approximately 6 years for the ringed seal populations and 14 years in case of polar bears. Since then a rapid decrease has occurred with clearing half-lives of approximately 1, 2 and 4 years, respectively. In polar bears perfluorohexane sulphonate (PFHxS) and perfluorooctane sulphonamide (PFOSA) also showed decreasing trends in recent years as do perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA). For the West Greenland ringed seal population perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), PFDA and PFUnA peaked in the mid 2000s, whereas PFNA, PFDA and PFUnA in the East Greenland population have been stable or increasing in recent years. The peak of PFASs in Greenland ringed seals and polar bears occurred at a later time than in Canadian seals and polar bears and considerably later than observed in seal species from more southern latitudes. We suggest that this could be explained by the distance to emission hot-spots and differences in long-range transport to the Arctic. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. A Linear Dynamical Systems Approach to Streamflow Reconstruction Reveals History of Regime Shifts in Northern Thailand

    Science.gov (United States)

    Nguyen, Hung T. T.; Galelli, Stefano

    2018-03-01

    Catchment dynamics is not often modeled in streamflow reconstruction studies; yet, the streamflow generation process depends on both catchment state and climatic inputs. To explicitly account for this interaction, we contribute a linear dynamic model, in which streamflow is a function of both catchment state (i.e., wet/dry) and paleoclimatic proxies. The model is learned using a novel variant of the Expectation-Maximization algorithm, and it is used with a paleo drought record—the Monsoon Asia Drought Atlas—to reconstruct 406 years of streamflow for the Ping River (northern Thailand). Results for the instrumental period show that the dynamic model has higher accuracy than conventional linear regression; all performance scores improve by 45-497%. Furthermore, the reconstructed trajectory of the state variable provides valuable insights about the catchment history—e.g., regime-like behavior—thereby complementing the information contained in the reconstructed streamflow time series. The proposed technique can replace linear regression, since it only requires information on streamflow and climatic proxies (e.g., tree-rings, drought indices); furthermore, it is capable of readily generating stochastic streamflow replicates. With a marginal increase in computational requirements, the dynamic model brings more desirable features and value to streamflow reconstructions.

  14. A regime shift in the Sun-Climate connection with the end of the Medieval Climate Anomaly.

    Science.gov (United States)

    Smirnov, D A; Breitenbach, S F M; Feulner, G; Lechleitner, F A; Prufer, K M; Baldini, J U L; Marwan, N; Kurths, J

    2017-09-11

    Understanding the influence of changes in solar activity on Earth's climate and distinguishing it from other forcings, such as volcanic activity, remains a major challenge for palaeoclimatology. This problem is best approached by investigating how these variables influenced past climate conditions as recorded in high precision paleoclimate archives. In particular, determining if the climate system response to these forcings changes through time is critical. Here we use the Wiener-Granger causality approach along with well-established cross-correlation analysis to investigate the causal relationship between solar activity, volcanic forcing, and climate as reflected in well-established Intertropical Convergence Zone (ITCZ) rainfall proxy records from Yok Balum Cave, southern Belize. Our analysis reveals a consistent influence of volcanic activity on regional Central American climate over the last two millennia. However, the coupling between solar variability and local climate varied with time, with a regime shift around 1000-1300 CE after which the solar-climate coupling weakened considerably.

  15. Evidence for a Drought-driven (pre-industrial) Regime Shift in an Australian Shallow Lake

    Science.gov (United States)

    Mills, K.; Gell, P.; Doan, P.; Kershaw, P.; McKenzie, M.; Lewis, T.; Tyler, J. J.

    2015-12-01

    We present a 750-year record of ecosystem response to long-term drought history from Lake Colac, Victoria. Using multiple lines of evidence, we test the sensitivity and resilience of Lake Colac to independently reconstructed drought history. The sedimentary archive shows that Lake Colac appears to be sensitive to periods of drought. Following drought conditions c. CE 1390, the lake ecosystem indicates signs of recovery. A succession of droughts in the early 1500s initiates a change in the diatom flora, with freshwater species declining and replaced by saline tolerant species, though there is little interpretable change in aquatic palynomorphs. An inferred drought, around CE 1720 appears to precede a major switch in the lake's ecosystem. The lake became increasingly turbid and saline and there is a distinct switch from a macrophyte-dominated system to an algal-dominated system. The arrival of Europeans in Victoria (CE1840) appears to have little effect on the lake's ecosystem, but the terrestrial vegetation indicates regionally established changes including declines in native trees, especially Casuarina, and arrival and expansion of exotic shade or plantation trees Pinus and Cupressus as well as native and introduced weeds. As European impact in the catchment increases, nutrients appear to play a role in the modification of the lake's ecosystem. A long-term drying trend from c. CE 1975 is evident, culminating in the Millennium Drought, which suggests unprecedented conditions in the ecological history of the Lake.

  16. Coastal regime shifts: rapid responses of coastal wetlands to changes in mangrove cover.

    Science.gov (United States)

    Guo, Hongyu; Weaver, Carolyn; Charles, Sean P; Whitt, Ashley; Dastidar, Sayantani; D'Odorico, Paolo; Fuentes, Jose D; Kominoski, John S; Armitage, Anna R; Pennings, Steven C

    2017-03-01

    Global changes are causing broad-scale shifts in vegetation communities worldwide, including coastal habitats where the borders between mangroves and salt marsh are in flux. Coastal habitats provide numerous ecosystem services of high economic value, but the consequences of variation in mangrove cover are poorly known. We experimentally manipulated mangrove cover in large plots to test a set of linked hypotheses regarding the effects of changes in mangrove cover. We found that changes in mangrove cover had strong effects on microclimate, plant community, sediment accretion, soil organic content, and bird abundance within 2 yr. At higher mangrove cover, wind speed declined and light interception by vegetation increased. Air and soil temperatures had hump-shaped relationships with mangrove cover. The cover of salt marsh plants decreased at higher mangrove cover. Wrack cover, the distance that wrack was distributed from the water's edge, and sediment accretion decreased at higher mangrove cover. Soil organic content increased with mangrove cover. Wading bird abundance decreased at higher mangrove cover. Many of these relationships were non-linear, with the greatest effects when mangrove cover varied from zero to intermediate values, and lesser effects when mangrove cover varied from intermediate to high values. Temporal and spatial variation in measured variables often peaked at intermediate mangrove cover, with ecological consequences that are largely unexplored. Because different processes varied in different ways with mangrove cover, the "optimum" cover of mangroves from a societal point of view will depend on which ecosystem services are most desired. © 2016 by the Ecological Society of America.

  17. Long term variability of the annual hydrological regime and sensitivity to temperature phase shifts in Saxony/Germany

    Science.gov (United States)

    Renner, M.; Bernhofer, C.

    2011-01-01

    The timing of the seasons strongly effects ecosystems and human activities. Recently, there is increasing evidence of changes in the timing of the seasons, such as earlier spring seasons detected in phenological records, advanced seasonal timing of surface temperature, earlier snow melt or streamflow timing. For water resources management there is a need to quantitatively describe the variability in the timing of hydrological regimes and to understand how climatic changes control the seasonal water budget of river basins on the regional scale. In this study, changes of the annual cycle of hydrological variables are analysed for 27 river basins in Saxony/Germany. Thereby monthly series of basin runoff ratios, the ratio of runoff and basin precipitation are investigated for changes and variability of their annual periodicity over the period 1930-2009. Approximating the annual cycle by the means of harmonic functions gave acceptable results, while only two parameters, phase and amplitude, are required. It has been found that the annual phase of runoff ratio, representing the timing of the hydrological regime, is subject to considerable year-to-year variability, being concurrent with basins in similar hydro-climatic conditions. Two distinct basin classes have been identified, whereby basin elevation has been found to be the delimiting factor. An increasing importance of snow on the basin water balance with elevation is apparent and mainly governs the temporal variability of the annual timing of hydrological regimes. Further there is evidence of coincident changes in trend direction (change points in 1971 and 1988) in snow melt influenced basins. In these basins the timing of the runoff ratio is significantly correlated with the timing of temperature, and effects on runoff by temperature phase changes are even amplified. Interestingly, temperature effects may explain the low frequent variability of the second change point until today. However, the first change point can

  18. Shift of subtropical transport barriers explains observed hemispheric asymmetry of decadal trends of age of air

    Directory of Open Access Journals (Sweden)

    G. P. Stiller

    2017-09-01

    Full Text Available In response to global warming, the Brewer–Dobson circulation in the stratosphere is expected to accelerate and the mean transport time of air along this circulation to decrease. This would imply a negative stratospheric age of air trend, i.e. an air parcel would need less time to travel from the tropopause to any point in the stratosphere. Age of air as inferred from tracer observations, however, shows zero to positive trends in the northern mid-latitude stratosphere and zonally asymmetric patterns. Using satellite observations and model calculations we show that the observed latitudinal and vertical patterns of the decadal changes of age of air in the lower to middle stratosphere during the period 2002–2012 are predominantly caused by a southward shift of the circulation pattern by about 5°. After correction for this shift, the observations reveal a hemispherically almost symmetric decrease of age of air in the lower to middle stratosphere up to 800 K of up to −0.25 years over the 2002–2012 period with strongest decrease in the northern tropics. This net change is consistent with long-term trends from model predictions.

  19. Understanding regime shifts

    DEFF Research Database (Denmark)

    Heymann, Matthias; Nielsen, Kristian Hvidtfelt

    Wind power was an important power source not only in the preindustrial era but also into the nineteenth and early twentieth century. In most regions by the mid twentieth century the ubiquitous windmill was quickly replaced by alternative power sources, mainly electricity. Efforts to revive wind...... in Denmark proved more successful than heavily funded efforts in the USA, Sweden or Germany. Within few years, Danish wind turbines dominated California wind parks and outclassed the turbines from other producers. Since the 1980s, all successful wind turbine producers copied basic features of “Danish Design...

  20. Task 1.5 Genomic Shift and Drift Trends of Emerging Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Borucki, M

    2010-01-05

    The Lawrence Livermore National Laboratory (LLNL) Bioinformatics group has recently taken on a role in DTRA's Transformation Medical Technologies Initiative (TMTI). The high-level goal of TMTI is to accelerate the development of broad-spectrum countermeasures. To achieve those goals, TMTI has a near term need to conduct analyses of genomic shift and drift trends of emerging pathogens, with a focused eye on select agent pathogens, as well as antibiotic and virulence markers. Most emerging human pathogens are zoonotic viruses with a genome composed of RNA. The high mutation rate of the replication enzymes of RNA viruses contributes to sequence drift and provides one mechanism for these viruses to adapt to diverse hosts (interspecies transmission events) and cause new human and zoonotic diseases. Additionally, new viral pathogens frequently emerge due to genetic shift (recombination and segment reassortment) which allows for dramatic genotypic and phenotypic changes to occur rapidly. Bacterial pathogens also evolve via genetic drift and shift, although sequence drift generally occurs at a much slower rate for bacteria as compared to RNA viruses. However, genetic shift such as lateral gene transfer and inter- and intragenomic recombination enables bacteria to rapidly acquire new mechanisms of survival and antibiotic resistance. New technologies such as rapid whole genome sequencing of bacterial genomes, ultra-deep sequencing of RNA virus populations, metagenomic studies of environments rich in antibiotic resistance genes, and the use of microarrays for the detection and characterization of emerging pathogens provide mechanisms to address the challenges posed by the rapid emergence of pathogens. Bioinformatic algorithms that enable efficient analysis of the massive amounts of data generated by these technologies as well computational modeling of protein structures and evolutionary processes need to be developed to allow the technology to fulfill its potential.

  1. Links between the recruitment success of northern European hake (Merluccius merluccius L.) and a regime shift on the NE Atlantic continental shelf

    KAUST Repository

    Goikoetxea, Nerea

    2013-07-01

    The distribution of northern European hake (Merluccius merluccius L.) extends from the Bay of Biscay up to Norwegian waters. However, despite its wide geographical distribution, there have been few studies on fluctuations in the European hake populations. Marine ecosystem shifts have been investigated worldwide and their influence on trophic levels has been studied, from top predator fish populations down to planktonic prey species, but there is little information on the effect of atmosphere-ocean shifts on European hake. This work analyses hake recruitment success (recruits per adult biomass) in relation to environmental changes over the period 1978-2006 in order to determine whether the regime shift identified in several abiotic and biotic variables in the North Sea also affected the Northeast Atlantic shelf oceanography. Hake recruitment success as well as parameters such as the sea surface temperature, wind patterns and copepod abundance changed significantly at the end of the 1980s, demonstrating an ecological regime shift in the Northeast Atlantic. Despite the low reproductive biomass recorded during the last decades, hake recruitment success has been higher since the change in 1989/90. The higher productivity may have sustained the population despite the intense fishing pressure; copepod abundance, warmer water temperatures and moderate eastward transport were found to be beneficial. In conclusion, in 1988/89 the Northeast Atlantic environment shifted to a favourable regime for northern hake production. This study supports the hypothesis that the hydro-climatic regime shift that affected the North Sea in the late 1980s may have influenced a wider region, such as the Northeast Atlantic. © 2013 John Wiley & Sons Ltd.

  2. Climate regime shifts in paleoclimate time series from the Yucatán Peninsula: from the Preclassic to Classic period

    Science.gov (United States)

    Polanco Martínez, Josue M.; Medina-Elizalde, Martin; Burns, Stephen J.; Jiang, Xiuyang; Shen, Chuan-Chou

    2015-04-01

    It has been widely accepted by the paleoclimate and archaeology communities that extreme climate events (especially droughts) and past climate change played an important role in the cultural changes that occurred in at least some parts of the Maya Lowlands, from the Pre-Classic (2000 BC to 250 AD) to Post-Classic periods (1000 to 1521 AD) [1, 2]. In particular, a large number of studies suggest that the decline of the Maya civilization in the Terminal Classic Period was greatly influenced by prolonged severe drought events that probably triggered significant societal disruptions [1, 3, 4, 5]. Going further on these issues, the aim of this work is to detect climate regime shifts in several paleoclimate time series from the Yucatán Peninsula (México) that have been used as rainfall proxies [3, 5, 6, 7]. In order to extract information from the paleoclimate data studied, we have used a change point method [8] as implemented in the R package strucchange, as well as the RAMFIT method [9]. The preliminary results show for all the records analysed a prominent regime shift between 400 to 200 BCE (from a noticeable increase to a remarkable fall in precipitation), which is strongest in the recently obtained stalagmite (Itzamna) delta18-O precipitation record [7]. References [1] Gunn, J. D., Matheny, R. T., Folan, W. J., 2002. Climate-change studies in the Maya area. Ancient Mesoamerica, 13(01), 79-84. [2] Yaeger, J., Hodell, D. A., 2008. The collapse of Maya civilization: assessing the interaction of culture, climate, and environment. El Niño, Catastrophism, and Culture Change in Ancient America, 197-251. [3] Hodell, D. A., Curtis, J. H., Brenner, M., 1995. Possible role of climate in the collapse of Classic Maya civilization. Nature, 375(6530), 391-394. [4] Aimers, J., Hodell, D., 2011. Societal collapse: Drought and the Maya. Nature 479(7371), 44-45 (2011). [5] Medina-Elizalde, M., Rohling, E. J., 2012. Collapse of Classic Maya civilization related to modest reduction

  3. Spatio-Temporal Analysis of Vegetation Dynamics in Relation to Shifting Inundation and Fire Regimes: Disentangling Environmental Variability from Land Management Decisions in a Southern African Transboundary Watershed

    Directory of Open Access Journals (Sweden)

    Narcisa G. Pricope

    2015-07-01

    Full Text Available Increasing temperatures and wildfire incidence and decreasing precipitation and river runoff in southern Africa are predicted to have a variety of impacts on the ecology, structure, and function of semi-arid savannas, which provide innumerable livelihood resources for millions of people. This paper builds on previous research that documents change in inundation and fire regimes in the Chobe River Basin (CRB in Namibia and Botswana and proposes to demonstrate a methodology that can be applied to disentangle the effect of environmental variability from land management decisions on changing and ecologically sensitive savanna ecosystems in transboundary contexts. We characterized the temporal dynamics (1985–2010 of vegetation productivity for the CRB using proxies of vegetation productivity and examine the relative importance of shifts in flooding and fire patterns to vegetation dynamics and effects of the association of phases of the El Niño—Southern Oscillation (ENSO on vegetation greenness. Our results indicate that vegetation in these semi-arid environments is highly responsive to climatic fluctuations and the long-term trend is one of increased but heterogeneous vegetation cover. The increased cover and heterogeneity during the growing season is especially noted in communally-managed areas of Botswana where long-term fire suppression has been instituted, in contrast to communal areas in Namibia where heterogeneity in vegetation cover is mostly increasing primarily outside of the growing season and may correspond to mosaic early dry season burns. Observed patterns of increased vegetation productivity and heterogeneity may relate to more frequent and intense burning and higher spatial variability in surface water availability from both precipitation and regional inundation patterns, with implications for global environmental change and adaptation in subsistence-based communities.

  4. Seasonal marine growth of Bristol Bay sockeye salmon (Oncorhynchus nerka) in relation to competition with Asian pink salmon (O. gorbuscho) and the 1977 ocean regime shift

    Science.gov (United States)

    Ruggerone, Gregory T.; Farley, Ed; Nielsen, Jennifer L.; Hagen, Peter

    2005-01-01

    Recent research demonstrated significantly lower growth and survival of Bristol Bay sockeye salmon (Oncorhynchus nerka) during odd-numbered years of their second or third years at sea (1975, 1977, etc.), a trend that was opposite that of Asian pink salmon (O. gorbuscha) abundance. Here we evaluated seasonal growth trends of Kvichak and Egegik river sockeye salmon (Bristol Bay stocks) during even- and odd-numbered years at sea by measuring scale circuli increments within each growth zone of each major salmon age group between 1955 and 2000. First year scale growth was not significantly different between odd- and even-numbered years, but peak growth of age-2. smolts was significantly higher than age-1 smolts. Total second and third year scale growth of salmon was significantly lower during odd- than during even-numbered years. However, reduced scale growth in odd-numbered years began after peak growth in spring and continued through summer and fall even though most pink salmon had left the high seas by late July (10-18% growth reduction in odd vs. even years). The alternating odd and even year growth pattern was consistent before and after the 1977 ocean regime shift. During 1977-2000, when salmon abundance was relatively great, sockeye salmon growth was high during specific seasons compared with that during 1955-1976, that is to say, immediately after entry to Bristol Bay, after peak growth in the first year, during the middle of the second growing season, and during spring of the third season. Growth after the spring peak in the third year at sea was relatively low during 1977-2000. We hypothesize that high consumption rates of prey by pink salmon during spring through mid-July of odd-numbered years, coupled with declining zooplankton biomass during summer and potentially cyclic abundances of squid and other prey, contributed to reduced prey availability and therefore reduced growth of Bristol Bay sockeye salmon during late spring through fall of odd-numbered years.

  5. The Behavior of Interest Rate Differentials Under Shifting Exchange Rate Regimes: The Experience of Chile, Colombia and Israel

    OpenAIRE

    Carlos Ibarra

    2005-01-01

    This paper studies the dynamics of the interest rate differential across band and floating exchange rate regimes in Chile, Colombia and Israel, and in a benchmark group composed of Italy, Portugal and Spain. Significant differences in the interest rate-exchange rate link are found between the two groups, irrespective of regime. However, in all countries, except Italy, the interest differential ceased to behave anti-cyclically against output after the adoption of floating, possibly because of ...

  6. Limnological regime shifts caused by climate warming and Lesser Snow Goose population expansion in the western Hudson Bay Lowlands (Manitoba, Canada).

    Science.gov (United States)

    MacDonald, Lauren A; Farquharson, Nicole; Merritt, Gillian; Fooks, Sam; Medeiros, Andrew S; Hall, Roland I; Wolfe, Brent B; Macrae, Merrin L; Sweetman, Jon N

    2015-02-01

    Shallow lakes are dominant features in subarctic and Arctic landscapes and are responsive to multiple stressors, which can lead to rapid changes in limnological regimes with consequences for aquatic resources. We address this theme in the coastal tundra region of Wapusk National Park, western Hudson Bay Lowlands (Canada), where climate has warmed during the past century and the Lesser Snow Goose (LSG; Chen caerulescens caerulescens) population has grown rapidly during the past ∽40 years. Integration of limnological and paleolimnological analyses documents profound responses of productivity, nutrient cycling, and aquatic habitat to warming at three ponds ("WAP 12", "WAP 20", and "WAP 21″), and to LSG disturbance at the two ponds located in an active nesting area (WAP 20, WAP 21). Based on multiparameter analysis of (210)Pb-dated sediment records from all three ponds, a regime shift occurred between 1875 and 1900 CE marked by a transition from low productivity, turbid, and nutrient-poor conditions of the Little Ice Age to conditions of higher productivity, lower nitrogen availability, and the development of benthic biofilm habitat as a result of climate warming. Beginning in the mid-1970s, sediment records from WAP 20 and WAP 21 reveal a second regime shift characterized by accelerated productivity and increased nitrogen availability. Coupled with 3 years of limnological data, results suggest that increased productivity at WAP 20 and WAP 21 led to atmospheric CO2 invasion to meet algal photosynthetic demand. This limnological regime shift is attributed to an increase in the supply of catchment-derived nutrients from the arrival of LSG and their subsequent disturbance to the landscape. Collectively, findings discriminate the consequences of warming and LSG disturbance on tundra ponds from which we identify a suite of sensitive limnological and paleolimnological measures that can be utilized to inform aquatic ecosystem monitoring.

  7. Rainfall and runoff regime trends in mountain catchments (Case study area: the upper Hron River basin, Slovakia

    Directory of Open Access Journals (Sweden)

    Blahušiaková Andrea

    2015-09-01

    Full Text Available This paper presents an analysis of trends and causes of changes of selected hydroclimatic variables influencing the runoff regime in the upper Hron River basin (Slovakia. Different methods for identifying trends in data series are evaluated and include: simple mass curve analysis, linear regression, frequency analysis of flood events, use of the Indicators of Hydrological Alteration software, and the Mann-Kendall test. Analyses are performed for data from two periods (1931-2010 and 1961-2010. The changes in runoff are significant, especially in terms of lower QMax and 75 percentile values. This fact is also confirmed by the lower frequency and extremity of flood events. The 1980s are considered a turning point in the development of all hydroclimatic variables. The Mann-Kendall test shows a significant decrease in runoff in the winter period. The main causes of runoff decline are: the considerable increase in air temperature, the decrease in snow cover depth and changes in seasonal distribution of precipitation amounts.

  8. Shifts in dynamic regime of an invasive lady beetle are linked to the invasion and insecticidal management of its prey

    NARCIS (Netherlands)

    Bahlai, C.A.; Werf, van der W.; O'Neal, M.; Hemerik, L.; Landis, D.A.

    2015-01-01

    The spread and impact of invasive species may vary over time in relation to changes in the species itself, the biological community of which it is part, or external controls on the system. Here we investigate whether there have been changes in dynamic regimes over the last 20 years of two invasive

  9. Recent shifts in Himalayan vegetation activity trends in response to climatic change and environmental drivers

    Science.gov (United States)

    Mishra, N. B.; Mainali, K. P.

    2016-12-01

    Climatic changes along with anthropogenic disturbances are causing dramatic ecological impacts in mid to high latitude mountain vegetation including in the Himalayas which are ecologically sensitive environments. Given the challenges associated with in situ vegetation monitoring in the Himalayas, remote sensing based quantification of vegetation dynamics can provide essential ecological information on changes in vegetation activity that may consist of alternative sequence of greening and/or browning periods. This study utilized a trend break analysis procedure for detection of monotonic as well as abrupt (either interruption or reversal) trend changes in smoothed normalized difference vegetation index satellite time-series data over the Himalayas. Overall, trend breaks in vegetation greenness showed high spatio-temporal variability in distribution considering elevation, ecoregion and land cover/use stratifications. Interrupted greening was spatially most dominant in all Himalayan ecoregions followed by abrupt browning. Areas showing trend reversal and monotonic trends appeared minority. Trend type distribution was strongly dependent on elevation as majority of greening (with or without interruption) occurred at lower elevation areas at higher elevation were dominantly. Ecoregion based stratification of trend types highlighted some exception to this elevational dependence as high altitude ecoregions of western Himalayas showed significantly less browning compared to the ecoregions in eastern Himalaya. Land cover/use based analysis of trend distribution showed that interrupted greening was most dominant in closed needleleafed forest following by rainfed cropland and mosaic croplands while interrupted browning most dominant in closed to open herbaceous vegetation found at higher elevation areas followed by closed needleleafed forest and closed to open broad leafed evergreen forests. Spatial analysis of trend break timing showed that for majority of areas experiencing

  10. Mid- to late Holocene climate-driven regime shifts inferred from diatom, ostracod and stable isotope records from Lake Son Kol (Central Tian Shan, Kyrgyzstan)

    Science.gov (United States)

    Schwarz, Anja; Turner, Falko; Lauterbach, Stefan; Plessen, Birgit; Krahn, Kim J.; Glodniok, Sven; Mischke, Steffen; Stebich, Martina; Witt, Roman; Mingram, Jens; Schwalb, Antje

    2017-12-01

    Arid Central Asia represents a key region for understanding climate variability and interactions in the Northern Hemisphere. Patterns and mechanisms of Holocene climate change in arid Central Asia are, however, only partially understood. Multi-proxy data combining diatom, ostracod, sedimentological, geochemical and stable isotope analyses from a ca. 6000-year-old lake sediment core from Son Kol (Central Kyrgyzstan) show distinct and repeated changes in species assemblages. Diatom- and ostracod-inferred conductivity shifts between meso-euhaline and freshwater conditions suggest water balance and regime shifts. Organism-derived data are corroborated by stable isotope, mineralogical and geochemical records, underlining that Son Kol was affected by strong lake level fluctuations of several meters. The δ13Ccarb/δ18Ocarb correlation shows repeated switchovers from a closed to an open lake system. From 6000 to 3800 and 3250 to 1950 cal. yr BP, Son Kol was a closed basin lake with higher conductivities, increased nutrient availability and a water level located below the modern outflow. Son Kol became again a hydrologically open lake at 3800 and 1950 cal. yr BP. Comparisons to other local and regional paleoclimate records indicate that these regime shifts were largely controlled by changing intensity and position of the Westerlies and the Siberian Anticyclone that triggered changes in the amount of winter precipitation. A strong influence of the Westerlies ca. 5000-4400, 3800-3250 and since 1950 cal. yr BP enhanced the amount of precipitation during spring, autumn and winter, whereas cold and dry winters prevailed during phases with a strong Siberian Anticyclone and southward shifted Westerlies at ca. 6000-5000, 4400-3800 and 3250-1950 cal. yr BP. Similarities between variations in winter precipitation at Son Kol and records of the predominant NAO-mode further suggest a teleconnection between wet (dry) winter climate in Central Asia and a positive (negative) NAO

  11. From success to persistence: Identifying an evolutionary regime shift in the diverse Paleozoic aquatic arthropod group Eurypterida, driven by the Devonian biotic crisis.

    Science.gov (United States)

    Lamsdell, James C; Selden, Paul A

    2017-01-01

    Mass extinctions have altered the trajectory of evolution a number of times over the Phanerozoic. During these periods of biotic upheaval a different selective regime appears to operate, although it is still unclear whether consistent survivorship rules apply across different extinction events. We compare variations in diversity and disparity across the evolutionary history of a major Paleozoic arthropod group, the Eurypterida. Using these data, we explore the group's transition from a successful, dynamic clade to a stagnant persistent lineage, pinpointing the Devonian as the period during which this evolutionary regime shift occurred. The late Devonian biotic crisis is potentially unique among the "Big Five" mass extinctions in exhibiting a drop in speciation rates rather than an increase in extinction. Our study reveals eurypterids show depressed speciation rates throughout the Devonian but no abnormal peaks in extinction. Loss of morphospace occupation is random across all Paleozoic extinction events; however, differential origination during the Devonian results in a migration and subsequent stagnation of occupied morphospace. This shift appears linked to an ecological transition from euryhaline taxa to freshwater species with low morphological diversity alongside a decrease in endemism. These results demonstrate the importance of the Devonian biotic crisis in reshaping Paleozoic ecosystems. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  12. Observed trends of soil fauna in the Antarctic Dry Valleys: early signs of shifts predicted under climate change.

    Science.gov (United States)

    Andriuzzi, W S; Adams, B J; Barrett, J E; Virginia, R A; Wall, D H

    2018-02-01

    Long-term observations of ecological communities are necessary for generating and testing predictions of ecosystem responses to climate change. We investigated temporal trends and spatial patterns of soil fauna along similar environmental gradients in three sites of the McMurdo Dry Valleys, Antarctica, spanning two distinct climatic phases: a decadal cooling trend from the early 1990s through the austral summer of February 2001, followed by a shift to the current trend of warming summers and more frequent discrete warming events. After February 2001, we observed a decline in the dominant species (the nematode Scottnema lindsayae) and increased abundance and expanded distribution of less common taxa (rotifers, tardigrades, and other nematode species). Such diverging responses have resulted in slightly greater evenness and spatial homogeneity of taxa. However, total abundance of soil fauna appears to be declining, as positive trends of the less common species so far have not compensated for the declining numbers of the dominant species. Interannual variation in the proportion of juveniles in the dominant species was consistent across sites, whereas trends in abundance varied more. Structural equation modeling supports the hypothesis that the observed biological trends arose from dissimilar responses by dominant and less common species to pulses of water availability resulting from enhanced ice melt. No direct effects of mean summer temperature were found, but there is evidence of indirect effects via its weak but significant positive relationship with soil moisture. Our findings show that combining an understanding of species responses to environmental change with long-term observations in the field can provide a context for validating and refining predictions of ecological trends in the abundance and diversity of soil fauna. © 2018 by the Ecological Society of America.

  13. Resilience, Regime Shifts, and Guided Transition under Climate Change: Examining the Practical Difficulties of Managing Continually Changing Systems

    Directory of Open Access Journals (Sweden)

    Brenda B. Lin

    2013-03-01

    Full Text Available Managing terrestrial systems has become increasingly difficult under climate change as unidirectional shifts in climate conditions challenge the resilience of ecosystems to maintain their compositional structure and function. Despite the increased attention of resilience management to guide transformational change, questions remain as to how to apply resilience to manage transitions. Rather than pushing systems across thresholds into alternative states, climate change may create a stepwise progression of unknown transitional states that track changing climate conditions. Because of this uncertainty, we must find ways to guide transitioning systems across climate boundaries towards states that are socially and environmentally desirable. We propose to ease the uncertainty of managing shifting systems by providing an approach to adaptive management that we call guided transition, where socially and environmentally important ecosystem functions are preserved through transitions by considering and maintaining the species and structures needed for the desired functions. Scientifically, it will require a better understanding of the relationships between structure, species composition, and function for specific systems. Managers will also need to identify important functions at the local, regional, and national scale, and to determine how best to transition systems to a desired state based on existing scientific knowledge. Guided transition, therefore, helps guide the process of adaptive management by specifying a function-based management pathway that guides transitions through climatic changes.

  14. The Shifting Discourses of Educational Leadership: International Trends and Scotland's Response

    Science.gov (United States)

    Torrance, Deirdre; Humes, Walter

    2015-01-01

    Increasing emphasis has been placed on leadership within educational theory, policy and practice. Drawing on a wide range of academic literature and policy documents, this paper explores how the discourse of leadership has shifted and for what purposes. The authors are critical of the lack of conceptual underpinning for that discourse, evident…

  15. Trends in age of smoking initiation in the Netherlands: a shift towards older ages?

    NARCIS (Netherlands)

    Nuyts, Paulien A. W.; Kuipers, Mirte A. G.; Willemsen, Marc C.; Kunst, Anton E.

    2018-01-01

    Background and aim As smoking initiation generally occurs in adolescence, smoking prevention is targeted primarily at young adolescents (aged below 16 years). We hypothesize that, with the adoption of increasingly stronger youth access laws, a shift in the age of smoking initiation may have

  16. Two Regimes of Bandgap Red Shift and Partial Ambient Retention in Pressure-Treated Two-Dimensional Perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China; Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, United States; Kong, Lingping [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China; Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, United States; Guo, Peijun [Center; Stoumpos, Constantinos C. [Department; Hu, Qingyang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China; Liu, Zhenxian [Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, United States; Cai, Zhonghou [Advanced; Gosztola, David J. [Center; Mao, Ho-kwang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China; Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, United States; Kanatzidis, Mercouri G. [Department; Schaller, Richard D. [Center; Department

    2017-10-09

    The discovery of elevated environmental stability in two-dimensional (2D) Ruddlesden–Popper hybrid perovskites represents a significant advance in low-cost, high-efficiency light absorbers. In comparison to 3D counterparts, 2D perovskites of organo-lead-halides exhibit wider, quantum-confined optical bandgaps that reduce the wavelength range of light absorption. Here, we characterize the structural and optical properties of 2D hybrid perovskites as a function of hydrostatic pressure. We observe bandgap narrowing with pressure of 633 meV that is partially retained following pressure release due to an atomic reconfiguration mechanism. We identify two distinct regimes of compression dominated by the softer organic and less compressible inorganic sublattices. Our findings, which also include PL enhancement, correlate well with density functional theory calculations and establish structure–property relationships at the atomic scale. These concepts can be expanded into other hybrid perovskites and suggest that pressure/strain processing could offer a new route to improved materials-by-design in applications.

  17. ENSO regimes and the late 1970's climate shift: The role of synoptic weather and South Pacific ocean spiciness

    International Nuclear Information System (INIS)

    O'Kane, Terence J.; Matear, Richard J.; Chamberlain, Matthew A.; Oke, Peter R.

    2014-01-01

    South Pacific subtropical density compensated temperature and salinity (spiciness) anomalies are known to be associated with decadal equatorial variability, however, the mechanisms by which such disturbances are generated, advect and the degree to which they modulate the equatorial thermocline remains controversial. During the late 1970's a climate regime transition preceded a period of strong and sustained El Nino events. Using an ocean general circulation model forced by the constituent mechanical and thermodynamic components of the reanalysed atmosphere we show that the late 1970's transition coincided with the arrival of a large-scale, subsurface cold and fresh water anomaly in the central tropical Pacific. An ocean reanalysis for the period 1990–2007 that assimilates subsurface Argo, XBT and CTD data, reveals that disturbances occur due to the subduction of negative surface salinity anomalies from near 30° S, 100° W which are advected along the σ=25–26 kgm −3 isopycnal surfaces. These anomalies take, on average, seven years to reach the central equatorial Pacific where they may substantially perturb the thermocline before the remnants ultimately ventilate in the region of the western Pacific warm pool. Positive (warm–salty) disturbances, known to occur due to late winter diapycnal mixing and isopycnal outcropping, arise due to both subduction of subtropical mode waters and subsurface injection. On reaching the equatorial band (10° S–0° S) these disturbances tend to deepen the thermocline reducing the model's ENSO. In contrast the emergence of negative (cold–fresh) disturbances at the equator are associated with a shoaling of the thermocline and El Nino events. Process studies are used to show that the generation and advection of anomalous density compensated thermocline disturbances critically depend on stochastic forcing of the intrinsic ocean by weather. We further show that in the absence of the inter-annual component of the atmosphere

  18. Regime shift of Indian summer monsoon rainfall to a persistent arid state: external forcing versus internal variability

    Science.gov (United States)

    Srivastava, Ankur; Pradhan, Maheswar; Goswami, B. N.; Rao, Suryachandra A.

    2017-11-01

    The high propensity of deficient monsoon rainfall over the Indian sub-continent in the recent 3 decades (seven deficient monsoons against 3 excess monsoon years) compared to the prior 3 decades has serious implications on the food and water resources in the country. Motivated by the need to understand the high occurrence of deficient monsoon during this period, we examine the change in predictability of the Indian summer monsoon (ISM) and its teleconnections with Indo-Pacific sea surface temperatures between the two periods. The shift in the tropical climate in the late 1970s appears to be one of the major reasons behind this. We find an increased predictability of the ISM in the recent 3 decades owing to reduced `internal' interannual variability (IAV) due to the high-frequency modes, while the `external' IAV arising from the low-frequency modes has remained largely the same. The Indian Ocean Dipole-ISM teleconnection has become positive during the monsoon season in the recent period thereby compensating for the weakened ENSO-ISM teleconnection. The central Pacific El-Niño and the Indian Ocean (IO) warming during the recent 3 decades are working together to realise enhanced ascending motion in the equatorial IO between 70°E and 100°E, preconditioning the Indian monsoon system prone to a deficient state.

  19. Tracking Equilibrium and Nonequilibrium Shifts in Data with TREND

    OpenAIRE

    Xu, Jia; Van Doren, Steven R.

    2017-01-01

    Principal component analysis (PCA) discovers patterns in multivariate data that include spectra, microscopy, and other biophysical measurements. Direct application of PCA to crowded spectra, images, and movies (without selecting peaks or features) was shown recently to identify their equilibrium or temporal changes. To enable the community to utilize these capabilities with a wide range of measurements, we have developed multiplatform software named TREND to Track Equilibrium and Nonequilibri...

  20. A Model-Based Approach to Infer Shifts in Regional Fire Regimes Over Time Using Sediment Charcoal Records

    Science.gov (United States)

    Itter, M.; Finley, A. O.; Hooten, M.; Higuera, P. E.; Marlon, J. R.; McLachlan, J. S.; Kelly, R.

    2016-12-01

    deposition rate exhibits changes over time coincident with major climatic and vegetation shifts over the past 10,000 years. Ongoing work will use the regional charcoal deposition rate to estimate changes in biomass burned as a function of climate variability and regional vegetation pattern.

  1. Trend shifts in satellite-derived vegetation growth in Central Eurasia, 1982-2013.

    Science.gov (United States)

    Xu, Hao-Jie; Wang, Xin-Ping; Yang, Tai-Bao

    2017-02-01

    Central Eurasian vegetation is critical for the regional ecological security and the global carbon cycle. However, climatic impacts on vegetation growth in Central Eurasia are uncertain. The reason for this uncertainty lies in the fact that the response of vegetation to climate change showed nonlinearity, seasonality and differences among plant functional types. Based on remotely sensed vegetation index and in-situ meteorological data for the years 1982-2013, in conjunction with the latest land cover type product, we analyzed how vegetation growth trend varied across different seasons and evaluated vegetation response to climate variables at regional, biome and pixel scales. We found a persistent increase in the growing season NDVI over Central Eurasia during 1982-1994, whereas this greening trend has stalled since the mid-1990s in response to increased water deficit. The stalled trend in the growing season NDVI was largely attributed by summer and autumn NDVI changes. Enhanced spring vegetation growth after 2002 was caused by rapid spring warming. The response of vegetation to climatic factors varied in different seasons. Precipitation was the main climate driver for the growing season and summer vegetation growth. Changes in temperature and precipitation during winter and spring controlled the spring vegetation growth. Autumn vegetation growth was mainly dependent on the vegetation growth in summer. We found diverse responses of different vegetation types to climate drivers in Central Eurasia. Forests were more responsive to temperature than to precipitation. Grassland and desert vegetation responded more strongly to precipitation than to temperature in summer but more strongly to temperature than to precipitation in spring. In addition, the growth of desert vegetation was more dependent on winter precipitation than that of grasslands. This study has important implications for improving the performance of terrestrial ecosystem models to predict future vegetation

  2. Relativistic Spin-Orbit Heavy Atom on the Light Atom NMR Chemical Shifts: General Trends Across the Periodic Table Explained.

    Science.gov (United States)

    Vícha, Jan; Komorovsky, Stanislav; Repisky, Michal; Marek, Radek; Straka, Michal

    2018-05-10

    The importance of relativistic effects on the NMR parameters in heavy-atom (HA) compounds, particularly the SO-HALA (Spin-Orbit Heavy Atom on the Light Atom) effect on NMR chemical shifts, has been known for about 40 years. Yet, a general correlation between the electronic structure and SO-HALA effect has been missing. By analyzing 1 H NMR chemical shifts of the sixth-period hydrides (Cs-At), we discovered general electronic-structure principles and mechanisms that dictate the size and sign of the SO-HALA NMR chemical shifts. In brief, partially occupied HA valence shells induce relativistic shielding at the light atom (LA) nuclei, while empty HA valence shells induce relativistic deshielding. In particular, the LA nucleus is relativistically shielded in 5d 2 -5d 8 and 6p 4 HA hydrides and deshielded in 4f 0 , 5d 0 , 6s 0 , and 6p 0 HA hydrides. This general and intuitive concept explains periodic trends in the 1 H NMR chemical shifts along the sixth-period hydrides (Cs-At) studied in this work. We present substantial evidence that the introduced principles have a general validity across the periodic table and can be extended to nonhydride LAs. The decades-old question of why compounds with occupied frontier π molecular orbitals (MOs) cause SO-HALA shielding at the LA nuclei, while the frontier σ MOs cause deshielding is answered. We further derive connection between the SO-HALA NMR chemical shifts and Spin-Orbit-induced Electron Deformation Density (SO-EDD), a property that can be obtained easily from differential electron densities and can be represented graphically. SO-EDD provides an intuitive understanding of the SO-HALA effect in terms of the depletion/concentration of the electron density at LA nuclei caused by spin-orbit coupling due to HA in the presence of a magnetic field. Using an analogy between the SO-EDD concept and arguments from classic NMR theory, the complex question of the SO-HALA NMR chemical shifts becomes easily understandable for a wide

  3. Support effects and catalytic trends for water gas shift activity of transition metals

    DEFF Research Database (Denmark)

    Boisen, Astrid; Janssens, T.V.W.; Schumacher, Nana Maria Pii

    2010-01-01

    Water gas shift activity measurements for 12 transition metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Re, Ir, Pt, Au) supported on inert MgAl2O4 and Ce0.75Zr0.25O2 are presented, to elucidate the influence of the active metal and the support. The activity is related to the adsorption energy of molecular...... activity on the MgAl2O4 support and are both characterized by weak CO adsorption. For the MgAl2O4-supported catalysts a volcano-type relation between the activity and the adsorption energy of atomic oxygen on the metal is obtained. The maximum activity is found for metals with a binding energy of oxygen...... around −2.5 eV. No clear correlation exists with the adsorption energy of CO. In contrast, the activity for the Ce0.75Zr0.25O2 support increases with increasing adsorption strength for CO, and based on a relatively low activity of Cu the activity does not seem to depend on the adsorption energy of oxygen...

  4. Terrorism and Political Violence in Africa: Contemporary Trends in a Shifting Terrain

    Directory of Open Access Journals (Sweden)

    James J.F. Forest

    2011-09-01

    Full Text Available In 1994, Martha Crenshaw’s edited volume Terrorism in Africa made clear how terrorism – generally defined as a tactic that uses violence or the threat of violence as a coercive strategy to cause fear and political intimidation – was a feature within resistance movements, military coups, political assassinations, and various intra- and inter-state wars that have affected most African states at some point during the continent’s transition to independence and subsequent post-colonial period.  Crenshaw further noted that terrorism was not “an isolated phenomenon” for African states or the region more broadly [1]. This description remains salient today: terrorism has been a global phenomenon for many decades, and Africa has not been unscathed by it. Terrorism is just one of several types of political violence that states and their citizens, in Africa and elsewhere, have had to grapple with. In fact, from a macro perspective, terrorism may not be universally seen as the most important security challenge faced by African states and their citizens. Famine, drought, endemic poverty, diseases and other natural and man-made disasters that undermine human security have also been at the forefront of recent policy discussions on Africa among Western governments and international aid organizations. It is thus necessary to place terrorism within the broader terrain of Africa’s security challenges, before examining the historical trends and specific examples discussed in this Special Issue of Perspectives on Terrorism.

  5. Trends in energy intake in U.S. between 1977 and 1996: similar shifts seen across age groups.

    Science.gov (United States)

    Nielsen, Samara Joy; Siega-Riz, Anna Maria; Popkin, Barry M

    2002-05-01

    To determine the trends in locations and food sources of Americans stratified by age group for both total energy and the meal and snack subcomponents. Nationally representative data was taken from the 1977 to 1978 Nationwide Food Consumption Survey and the 1989 to 1991 and 1994 to 1996 (and 1998 for children age 2 through 9) Continuing Surveys of Food Intake by Individuals. The sample consisted of 63,380 individuals, age 2 and up. For each survey year, the percentage of total energy intake from meals and snacks was calculated separately for 2- to 18-year-olds, 19- to 39-year-olds, 40- to 59-year-olds, and those 60 years and older. The percentage of energy intake by location (at-home consumption or preparation, vending, store eaten out, restaurant/fast-food, and school) and by specific food group was computed for all age groups separately. The trends in location and food sources were almost identical for all age groups. Key dietary behavior shifts included greater away-from-home consumption; large increases in total energy from salty snacks, soft drinks, and pizza; and large decreases in energy from low- and medium-fat milk and medium- and high-fat beef and pork. Total energy intake has increased over the past 20 years, with shifts away from meals to snacks and from at-home to away-from-home consumption. The similarity of changes across all age groups furthers the assertion that broad-based environmental changes are needed to improve the diets of Americans.

  6. Lead-lag cross-sectional structure and detection of correlated anticorrelated regime shifts: Application to the volatilities of inflation and economic growth rates

    Science.gov (United States)

    Zhou, Wei-Xing; Sornette, Didier

    2007-07-01

    We have recently introduced the “thermal optimal path” (TOP) method to investigate the real-time lead-lag structure between two time series. The TOP method consists in searching for a robust noise-averaged optimal path of the distance matrix along which the two time series have the greatest similarity. Here, we generalize the TOP method by introducing a more general definition of distance which takes into account possible regime shifts between positive and negative correlations. This generalization to track possible changes of correlation signs is able to identify possible transitions from one convention (or consensus) to another. Numerical simulations on synthetic time series verify that the new TOP method performs as expected even in the presence of substantial noise. We then apply it to investigate changes of convention in the dependence structure between the historical volatilities of the USA inflation rate and economic growth rate. Several measures show that the new TOP method significantly outperforms standard cross-correlation methods.

  7. Historical shifts in oxygenation regime as recorded in the laminated sediments of lake Montcortès (Central Pyrenees) support hypoxia as a continental-scale phenomenon.

    Science.gov (United States)

    Vegas-Vilarrúbia, Teresa; Corella, Juan Pablo; Pérez-Zanón, Núria; Buchaca, Teresa; Trapote, M Carmen; López, Pilar; Sigró, Javier; Rull, Valentí

    2018-01-15

    Recent expansion of anoxia has become a global issue and there is potential for worsening under global warming. At the same time, obtaining proper long-term instrumental oxygen records is difficult, thus reducing the possibility of recording long-term changes in oxygen shifts that can be related with climate or human influence. Varved lake sediments provide the better time frame to study this phenomenon at high resolution. We tracked the oxic/anoxic shifts of the varved Lake Montcortès since 1500CE, and tried to recognise anthropogenic and climatic influences combining biological and geochemical proxies. Four main scenarios emerged: 1) years with abrupt sediment inputs (A); 2) years with outstanding mixing and oxygenation of the water column (B); 3) years with strong stratification, anoxia, intense sulfur bacterial activity and increased biomass production (C); 4) years with stratification and anoxia, but relatively less biomass production (D). In line with current limnologic trends, high supra-annual variability in the occurrence of oxygenation events was observed. Interestingly, at least 45.3% of the years were mixing years and, like the meromictic ones, were mostly clustered into groups of consecutive years, thus alternating years of monomixis with years of meromixis. Most years of D belong to the period 1500-1820CE, when human activities were the most intense. Most years of A belonged to the climatic unstable period of 1850-1899CE. Years of B were irregularly distributed but were best represented in the period 1820-1849CE. Most years of C belonged to the 20th century. More than 90% of the years with climatic instrumental records belonged to B and C. Current climate warming seems to be taking control over the oxygenation capacity of the lake, especially since the second half of the 20th century. Our results support recent findings related to hypoxia spreading at the global scale. Copyright © 2017. Published by Elsevier B.V.

  8. Trends and challenges in global arms control regimes: Implications for the Mediterranean, North Africa, and the Middle East

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, R.F. II

    1994-06-01

    In another sense, however, the nuclear age and ballistic missiles long ago created a much smaller world in which the distinctions between global and regional security have been lessened. In an age of weapons of mass destruction, any point on the earth can find itself suddenly at the center of world attention. This makes it all the more important that we understand all of the arms control tools available, including global approaches. In discussing global arms control regimes, I will focus primarily on those that are open to universal membership such as the Nuclear Nonproliferation Treaty (NPT) or which have global reach, such as certain export control and supplier regimes. It is important to remember, however, that certain regional, bilateral, and even unilateral arms control measures can have a global impact as well. One need only witness the impact of the Treaty on Conventional Forces in Europe (CFE). Despite its mere {open_quotes}Atlantic to the Urals{close_quotes} focus, the CFE treaty helped change the political and strategic calculations of the entire world. Likewise, the Conference on Security and Cooperation in Europe (CSCE), with its headquarters in Vienna, is centered on Europe but spreads from Vancouver to Vladivostok (or perhaps we should say from Amchitka to Kamchatka), circumnavigating much of the northern hemisphere when measured the long way around via North America. The political significance of its successes and failures outdistance CSCE`s geographical spread.

  9. Study of recent and future trends in place of death in Belgium using death certificate data: a shift from hospitals to care homes

    NARCIS (Netherlands)

    Houttekier, D.; Cohen, J.; Surkyn, J.; Deliens, L.

    2011-01-01

    Background: Since most patients prefer out-of-hospital death, place of death can be considered an indicator of end-of-life care quality. The study of trends in place of death is necessary to examine causes of shifts, to evaluate efforts to alter place of death and develop future policies. This study

  10. Trend in coral-algal phase shift in the Mandapam group of islands, Gulf of Mannar Marine Biosphere Reserve, India

    Science.gov (United States)

    Machendiranathan, M.; Senthilnathan, L.; Ranith, R.; Saravanakumar, A.; Thangaradjou, T.; Choudhry, S. B.; Sasamal, S. K.

    2016-12-01

    The present study revealed proliferation of macro-algae modifying coral reef ecosystems in a different manner due to diseases and sedimentations in the Mandapam group of islands in the Gulf of Mannar. Benthic surveys were conducted with major attack of seven coral reefs diseases with high sedimentation rate, nine species of fleshy macro-algae ( Turbinaria ornata, Turbinaria conaides, Caulerpa scalpelliformis, Caulerpa racemosa, Kappaphycus alvarezii, Padina gymnosphora, Sargassum wightii, Ulva reticulata and Calurpa lentillifera) proliferation against major corals life forms (Acropora branching, Acropora digitate, Acropora tabulate, coral massive, coral submassive, coral foliose and coral encrusting). The results confirm that diseased corals most favor to macro-algae growth (15.27%) rather than the sedimentation covered corals (8.24 %). In the degradation of coral life forms, massive corals were more highly damaged (7.05%) than any other forms. Within a short period of time (May to September), coral coverage shrank to 17.4% from 21.9%, macro-algae increased 23.51% and the average sedimentation rate attained 77.52 mg cm-2d-1 with persisting coral reef diseases of 17.59%. The Pearson correlation showed that the coral cover decreased with increasing macro-algae growth, which was statistically significant ( r = -0.774, n = 100, P K. alvarezii, P. gymnosphora and C. lentillifera increased with percentages of 6.0, 5.8, 5.7, 4.9, 4.2, 3.7, 2.7 and 1.9, respectively. If this trend continues, the next generation of new recruit corals will undoubtedly lead to a phase shift in Gulf of Mannar corals.

  11. Trends and structural shifts in health tourism: evidence from seasonal time-series data on health-related travel spending by Canada during 1970-2010.

    Science.gov (United States)

    Loh, Chung-Ping A

    2015-05-01

    There has been a growing interest in better understanding the trends and determinants of health tourism activities. While much of the expanding literature on health tourism offers theoretical or qualitative discussion, empirical evidences has been lacking. This study employs Canada's outbound health tourism activities as an example to examine the trends in health tourism and its association with changing domestic health care market characteristics. A time-series model that accounts for potential structural changes in the trend is employed to analyze the quarterly health-related travel spending series reported in the Balance of Payments Statistics (BOPS) during 1970-2010 (n = 156). We identified a structural shift point which marks the start of an accelerated growth of health tourism and a flattened seasonality in such activities. We found that the health tourism activities of Canadian consumers increase when the private investment in medical facilities declines or when the private MPI increases during the years following the structural-change. We discussed the possible linkage of the structural shift to the General Agreement on Trade in Services (GATS), which went into effect in January, 1995. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Is a shift from research on individual medical error to research on health information technology underway? A 40-year analysis of publication trends in medical journals.

    Science.gov (United States)

    Erlewein, Daniel; Bruni, Tommaso; Gadebusch Bondio, Mariacarla

    2018-06-07

    In 1983, McIntyre and Popper underscored the need for more openness in dealing with errors in medicine. Since then, much has been written on individual medical errors. Furthermore, at the beginning of the 21st century, researchers and medical practitioners increasingly approached individual medical errors through health information technology. Hence, the question arises whether the attention of biomedical researchers shifted from individual medical errors to health information technology. We ran a study to determine publication trends concerning individual medical errors and health information technology in medical journals over the last 40 years. We used the Medical Subject Headings (MeSH) taxonomy in the database MEDLINE. Each year, we analyzed the percentage of relevant publications to the total number of publications in MEDLINE. The trends identified were tested for statistical significance. Our analysis showed that the percentage of publications dealing with individual medical errors increased from 1976 until the beginning of the 21st century but began to drop in 2003. Both the upward and the downward trends were statistically significant (P information technology doubled between 2003 and 2015. The upward trend was statistically significant (P information technology in the USA and the UK. © 2018 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd.

  13. Identificando mudanças de regimes sistêmicos em processos econômicos: um procedimento baseado na abordagem de dinâmica de sistemas Identifying systemic regime shifts in economic processes: a procedure based on the system dynamics approach

    Directory of Open Access Journals (Sweden)

    Newton Paulo Bueno

    2013-04-01

    Full Text Available A tese deste trabalho é que as técnicas mais sofisticadas atualmente utilizadas pelos economistas para fazer previsões (métodos não estruturais de previsão, em geral, e modelos de detecção de mudanças de regime, em particular não parecem realmente muito eficazes em prever mudanças radicais de regime como a que ocorreu na economia mundial recentemente. Assim, para aumentar seu grau de acurácia, parece razoável imaginar que tais técnicas devam ser complementadas por abordagens mais holísticas. O objetivo geral deste trabalho é mostrar que a metodologia de dinâmica de sistemas (system dynamics, que permite identificar os ciclos de feedback que comandam a dinâmica de sistemas complexos, parece estar especialmente bem-equipada para se tornar uma dessas abordagens complementares. Pretende-se, especificamente, apresentar um algoritmo sistêmico para identificar processos de mudança de regime como os que ocorrem quando uma economia, após anos de expansão continuada, sofre os efeitos da explosão de uma bolha financeira, como ocorreu recentemente.This paper argues that the sophisticated techniques presently used by economists to forecast macroeconomic variables behavior (non-structural forecasting methods, in general, and regime-switching models, in particular do not seem much effective for anticipating radical regime shifts as recently happened in the world economy. Thus, in order to improve their accuracy, it seems that they should be complemented by more holistic approaches. The general purpose of the paper is to show that the system dynamics methodology, which allows identifying the critical feedback loops that drive complex systems' dynamics, seems to be especially fitted to be one of those complementary approaches. To reach that goal, we present a systemic algorithm which allows identifying regime shift processes as the ones that take place when an economy is hit by the effects of a financial bubble burst.

  14. Follow-up trends of parasite community alteration in a marine fish after the Prestige oil-spill: shifting baselines?

    Science.gov (United States)

    Pérez-del-Olmo, A; Montero, F E; Raga, J A; Fernández, M; Kostadinova, A

    2009-01-01

    This study evaluates the follow-up trends in the composition and structure of the parasite communities in the marine sparid Boops boops after the Prestige oil-spill. A total of 400 fish comprising 11 seasonal samples was analyzed from three impacted localities on the Atlantic coast of Spain. A large number of parasite species was recovered only after the spill thus suggesting a substantial alteration of the marine food webs. Post-spill communities exhibited higher richness and abundance due to the significant changes in the abundance of the common species, the latter indicating accelerated parasite transmission rates. Multivariate analyses at two nested scales detected a directional trend in parasite community succession towards the pre-spill situation, however, with no full support for community recovery. The state of parasite communities in 2005-2006 may provide the new baseline data which can serve as a framework for quantifying the impact of potential future spills in the region.

  15. Ecological regime shifts and changes of lake ecosystem service in a shallow Yangtze lake (Taibai Lake, China) over the past 150 years

    Science.gov (United States)

    Dong, X.; Xu, M.; Yang, X.

    2017-12-01

    Shallow lakes provide a range of ecosystem services such as water supply, biodiversity, aquaculture, tourism, shipping and flood regulation. Over recent decades, many lakes have become severely deteriorated due to a coupled natural and human disturbance. Given the limited monitoring records, however, we still have little knowledge on how, when and why those lake experienced ecological status shifts, and how the lake ecosystem service changed. Paleolimnological techniques were widely used in understanding the historical environmental and ecological changes. Here, we chose a typical eutrophic shallow lake, Taibai Lake, and acquired geochemistry proxies, grain size, diatom, cladocera and chironomid from a 210Pb and 137Cs dated sediment core. Document records and monitoring data are also included as important marks of social and environmental change. A T-test based algorithm of STARS reveal at least two ecological shifts, respectively in the 1960s and the 1990s. The sudden shift in the 1960s is supposed to be influenced by a dam and sluice construction in the 1950s and another shift in the 1990s should be a critical transition due to the alternation of ecosystem structure for higher fishery production. Correspondingly, lake ecosystem service (LES) also experienced significant changes. Prior to 1930s, different types of LES kept relatively stable with low values. With the dam construction in the 1960s, the changed hydrological condition led to gradual increases in both regulation and provision service. However, with much effort on fishery and reclamation, the regulation service of the lake decreased, exhibiting a tradeoff among LES. After 1990s, with intense aquaculture, most types of LSE suffered a further decrease. The long-term records exhibited that ecosystem services in primary productivity and biodiversity maintenance increased (synergies) whereas services in water-purification and climate regulating decreased significantly (tradeoffs) since 1950s, when local

  16. Study of recent and future trends in place of death in Belgium using death certificate data: a shift from hospitals to care homes

    Directory of Open Access Journals (Sweden)

    Deliens Luc

    2011-04-01

    Full Text Available Abstract Background Since most patients prefer out-of-hospital death, place of death can be considered an indicator of end-of-life care quality. The study of trends in place of death is necessary to examine causes of shifts, to evaluate efforts to alter place of death and develop future policies. This study aims to examine past trends and future projections of place of death. Methods Analysis of death certificates (decedents aged ≥ 1 year in Belgium (Flanders and Brussels Capital region 1998-2007. Trends in place of death were adjusted for cause of death, sociodemographic characteristics, environmental factors, numbers of hospital beds, and residential and skilled nursing beds in care homes. Future trends were based on age- and sex-specific mortality prognoses. Results Hospital deaths decreased from 55.1% to 51.7% and care home deaths rose from 18.3% to 22.6%. The percentage of home deaths remained stable. The odds of dying in a care home versus hospital increased steadily and was 1.65 (95%CI:1.53-1.78 in 2007 compared to 1998. This increase could be attributed to the replacement of residential beds by skilled nursing beds. Continuation of these trends would result in the more than doubling of deaths in care homes and a decrease in deaths at home and in hospital by 2040. Conclusions Additional end-of-life care resources in care homes largely explain the decrease in hospital deaths. Care homes will become the main locus of end-of-life care in the future. Governments should provide sufficient skilled nursing resources in care homes to fulfil the end-of-life care preferences and needs of patients.

  17. Trends in Education-Specific Life Expectancy, Data Quality, and Shifting Education Distributions: A Note on Recent Research.

    Science.gov (United States)

    Hendi, Arun S

    2017-06-01

    Several recent articles have reported conflicting conclusions about educational differences in life expectancy, and this is partly due to the use of unreliable data subject to a numerator-denominator bias previously reported as ranging from 20 % to 40 %. This article presents estimates of life expectancy and lifespan variation by education in the United States using more reliable data from the National Health Interview Survey. Contrary to prior conclusions in the literature, I find that life expectancy increased or stagnated since 1990 among all education-race-sex groups except for non-Hispanic white women with less than a high school education; there has been a robust increase in life expectancy among white high school graduates and a smaller increase among black female high school graduates; lifespan variation did not increase appreciably among high school graduates; and lifespan variation plays a very limited role in explaining educational gradients in mortality. I also discuss the key role that educational expansion may play in driving future changes in mortality gradients. Because of shifting education distributions, within an education-specific synthetic cohort, older age groups are less negatively selected than younger age groups. We could thus expect a greater concentration of mortality at younger ages among people with a high school education or less, which would be reflected in increasing lifespan variability for this group. Future studies of educational gradients in mortality should use more reliable data and should be mindful of the effects of shifting education distributions.

  18. Trends in the Types of Usual Sources of Care: A Shift from People to Places or Nothing at All.

    Science.gov (United States)

    Liaw, Winston; Jetty, Anuradha; Petterson, Stephen; Bazemore, Andrew; Green, Larry

    2017-08-31

    (1) To examine usual source of care (USC) trends across four categories (No USC, Person USC, Person, in Facility USC, and Facility USC), and (2) to determine whether USC types are associated with emergency department (ED) visits and hospital admissions. 1996-2014 Medical Expenditure Panel Surveys. We stratified each USC category, by age, region, gender, poverty, insurance, race/ethnicity, and education and used regression to determine the characteristics associated with USC types, ED visits, and hospital admissions. Those with No USC and Facility USCs increased 10 and 18 percent, respectively, while those with Person USCs decreased by 43 percent. Compared to those in the lowest income bracket, those in the highest income bracket were less likely to have a Facility USC. Among those with low incomes, individuals with No USC, Person, in Facility, and Facility USCs were more likely to have ED visits than those with Person USCs. A growing number are reporting facilities as their USCs or none at all. The impact of these trends is uncertain, although we found that some USC types are associated with ED visits and hospital admissions. Tracking USCs will be crucial to measuring progress toward enhanced care efficiency. © Health Research and Educational Trust.

  19. Follow-up trends of parasite community alteration in a marine fish after the Prestige oil-spill: Shifting baselines?

    International Nuclear Information System (INIS)

    Perez-del-Olmo, A.; Montero, F.E.; Raga, J.A.; Fernandez, M.; Kostadinova, A.

    2009-01-01

    This study evaluates the follow-up trends in the composition and structure of the parasite communities in the marine sparid Boops boops after the Prestige oil-spill. A total of 400 fish comprising 11 seasonal samples was analyzed from three impacted localities on the Atlantic coast of Spain. A large number of parasite species was recovered only after the spill thus suggesting a substantial alteration of the marine food webs. Post-spill communities exhibited higher richness and abundance due to the significant changes in the abundance of the common species, the latter indicating accelerated parasite transmission rates. Multivariate analyses at two nested scales detected a directional trend in parasite community succession towards the pre-spill situation, however, with no full support for community recovery. The state of parasite communities in 2005-2006 may provide the new baseline data which can serve as a framework for quantifying the impact of potential future spills in the region. - Prestige oil-spill impact on parasite communities in the sparid fish B. boops

  20. Shifting perspectives - Planning for the future of the pharmacy profession taking current labor market trends into consideration.

    Science.gov (United States)

    Traulsen, Janine Marie; Druedahl, Louise C

    2018-02-17

    The future of the pharmacy profession and concerns about professional identity have been popular and recurring themes in professional journals and at international pharmacy conferences for more than 30 years. The aim of this paper is to contribute to realistic and viable visions for the future of the pharmacy profession via insights through labor market and work organization theories. These insights provide an understanding of contemporary work patterns and what they mean for the future role of community pharmacists. It appears that an important and influential contemporary trend in work organization today is precarious work, i.e. non-standard employment that promotes and relies on a flexible and fluid work force. Contrary to permanent employment, precarious work is often poorly paid, insecure, unprotected, and in many cases cannot support a household. The growth of precarious work among professionals, including pharmacists has been documented in many countries. In the early 21st century a major concern in the UK was the growth in the number of pharmacists who choose to be self-employed "locums" as opposed to seeking permanent employment. With the spread of precarious work a new, involuntary form of employment appeared a decade later with the spread of "zero-hour contracts" and "exclusivity agreements". Particularly affected by these flexible, precarious work conditions are the highly-educated young health professionals such as pharmacists. The profession needs to be proactive in order to stay abreast of economic/workforce and organizational trends. The way forward is a commitment to a dynamic, knowledge-based vision that includes an ongoing analysis of the outside world. The core role of pharmacists in the future includes: 1. engagement in interprofessional education with other healthcare professionals; 2. an acceptance of the contribution that lay knowledge provides to the understanding of health and medicines, and 3.keeping ajour with new and revolutionary

  1. This time it's different. An inevitable decline in world petroleum production will keep oil product prices high, causing military conflicts and shifting wealth and power from democracies to authoritarian regimes

    Energy Technology Data Exchange (ETDEWEB)

    Leder, Frederic [2742 Sturges Highway, Westport, CT 06880 (United States); Shapiro, Judith N. [796 Sport Hill Road, Easton, CT 06612 (United States)

    2008-08-15

    There is virtual agreement among geologists that world production of conventional oil will peak at some point in the future. Oil, after all, is a finite resource, while demand will only grow over time. Geologists disagree, however, exactly when the peak will occur. Using data from the International Energy Agency, the US Department of Energy, the Association for the Study of Peak Oil and Gas, and petroleum industry sources, we argue that conventional oil production will reach a worldwide maximum within the next 5-10 years, earlier than generally estimated, thus leaving a very short time frame within which to plan for conversion to alternative sources of energy. Unless planning is initiated immediately, the United States and other Western democracies will see their positions in the global economy undercut as military conflicts over limited energy resources increase, and wealth and power are shifted to authoritarian regimes in Russia, Venezuela, Africa and the Middle East. (author)

  2. Flow regimes

    International Nuclear Information System (INIS)

    Kh'yuitt, G.

    1980-01-01

    An introduction into the problem of two-phase flows is presented. Flow regimes arizing in two-phase flows are described, and classification of these regimes is given. Structures of vertical and horizontal two-phase flows and a method of their identification using regime maps are considered. The limits of this method application are discussed. The flooding phenomena and phenomena of direction change (flow reversal) of the flow and interrelation of these phenomena as well as transitions from slug regime to churn one and from churn one to annular one in vertical flows are described. Problems of phase transitions and equilibrium are discussed. Flow regimes in tubes where evaporating liquid is running, are described [ru

  3. Flow regimes

    International Nuclear Information System (INIS)

    Liles, D.R.

    1982-01-01

    Internal boundaries in multiphase flow greatly complicate fluid-dynamic and heat-transfer descriptions. Different flow regimes or topological configurations can have radically dissimilar interfacial and wall mass, momentum, and energy exchanges. To model the flow dynamics properly requires estimates of these rates. In this paper the common flow regimes for gas-liquid systems are defined and the techniques used to estimate the extent of a particular regime are described. Also, the current computer-code procedures are delineated and introduce a potentially better method is introduced

  4. Evolving trends in Latin American regimes of science, technology and innovation: the politics of the “GM soya model” in Argentina

    OpenAIRE

    Delvenne, Pierre

    2011-01-01

    Our interest is to understand the challenges to modern (national) science and innovation regimes under conditions of globalization and “multiple modernities” (Eisenstadt 2000). Different scholarly attention has been paid to existing institutions that may no longer be adequate to address those challenges. This may be because modern institutions are pressured for a greater reflexive opening up of their structures (Beck and Lau 2005) or because the modern world-system is facing severe turbulence...

  5. Regime change?

    International Nuclear Information System (INIS)

    Pilat, Joseph F.; Budlong-Sylvester, K.W.

    2004-01-01

    Following the 1998 nuclear tests in South Asia and later reinforced by revelations about North Korean and Iraqi nuclear activities, there has been growing concern about increasing proliferation dangers. At the same time, the prospects of radiological/nuclear terrorism are seen to be rising - since 9/11, concern over a proliferation/terrorism nexus has never been higher. In the face of this growing danger, there are urgent calls for stronger measures to strengthen the current international nuclear nonproliferation regime, including recommendations to place civilian processing of weapon-useable material under multinational control. As well, there are calls for entirely new tools, including military options. As proliferation and terrorism concerns grow, the regime is under pressure and there is a temptation to consider fundamental changes to the regime. In this context, this paper will address the following: Do we need to change the regime centered on the Treaty on the Nonproliferation of Nuclear Weapons (NPT) and the International Atomic Energy Agency (IAEA)? What improvements could ensure it will be the foundation for the proliferation resistance and physical protection needed if nuclear power grows? What will make it a viable centerpiece of future nonproliferation and counterterrorism approaches?

  6. A long-term multi-proxy record of varved sediments highlights climate-induced mixing-regime shift in a large hard-water lake ~5000 years ago

    Directory of Open Access Journals (Sweden)

    Walter Finsinger

    2014-06-01

    Full Text Available The long-term terrestrial and aquatic ecosystem dynamics spanning between approximately 6200 and 4800 cal BP were investigated using pollen, diatoms, pigments, charcoal, and geochemistry from varved sediments collected in a large stratified perialpine lake, Lago Grande di Avigliana, in the Italian Alps. Marked changes were detected in diatom and pigment assemblages and in sediment composition at ~4900 cal BP. Organic matter rapidly increased and diatom assemblages shifted from oligotrophic to oligo-mesotrophic planktonic assemblages suggesting that nutrients increased at that time. Because land cover, erosion, and fire frequency did not change significantly, external nutrient sources were possibly not essential in controlling the lake-ecosystem dynamics. This is also supported by redundancy analysis, which showed that variables explaining significant amounts of variance in the diatom data were not the ones related to changes in the catchment. Instead, the broad coincidence between the phytoplankton dynamics and rising lake-levels, cooler temperatures, and stronger spring winds in the northern Mediterranean borderlands possibly points to the effects of climate change on the nutrient recycling in the lake by means of the control that climate can exert on mixing depth. We hypothesize that the increased P-release rates and higher organic-matter accumulation rates, proceeded by enhanced precipitation of iron sulphides, were possibly caused by deeper and stronger mixing leading to enhanced input of nutrients from the anoxic hypolimnion into the epilimnion. Although we cannot completely rule out the influence of minor land-cover changes due to human activities, it may be hypothesized that climate-induced cumulative effects related to mixing regime and P-recycling from sediments influenced the aquatic-ecosystem dynamics.

  7. Multiple long-term trends and trend reversals dominate environmental conditions in a man-made freshwater reservoir.

    Science.gov (United States)

    Znachor, Petr; Nedoma, Jiří; Hejzlar, Josef; Seďa, Jaromír; Kopáček, Jiří; Boukal, David; Mrkvička, Tomáš

    2018-05-15

    Man-made reservoirs are common across the world and provide a wide range of ecological services. Environmental conditions in riverine reservoirs are affected by the changing climate, catchment-wide processes and manipulations with the water level, and water abstraction from the reservoir. Long-term trends of environmental conditions in reservoirs thus reflect a wider range of drivers in comparison to lakes, which makes the understanding of reservoir dynamics more challenging. We analysed a 32-year time series of 36 environmental variables characterising weather, land use in the catchment, reservoir hydrochemistry, hydrology and light availability in the small, canyon-shaped Římov Reservoir in the Czech Republic to detect underlying trends, trend reversals and regime shifts. To do so, we fitted linear and piecewise linear regression and a regime shift model to the time series of mean annual values of each variable and to principal components produced by Principal Component Analysis. Models were weighted and ranked using Akaike information criterion and the model selection approach. Most environmental variables exhibited temporal changes that included time-varying trends and trend reversals. For instance, dissolved organic carbon showed a linear increasing trend while nitrate concentration or conductivity exemplified trend reversal. All trend reversals and cessations of temporal trends in reservoir hydrochemistry (except total phosphorus concentrations) occurred in the late 1980s and during 1990s as a consequence of dramatic socioeconomic changes. After a series of heavy rains in the late 1990s, an administrative decision to increase the flood-retention volume of the reservoir resulted in a significant regime shift in reservoir hydraulic conditions in 1999. Our analyses also highlight the utility of the model selection framework, based on relatively simple extensions of linear regression, to describe temporal trends in reservoir characteristics. This approach can

  8. Competition Regime

    Directory of Open Access Journals (Sweden)

    Danilo Icaza Ortiz

    2013-01-01

    Full Text Available This paper is a review of the competition regime works of various authors, published under the auspices of the University of the Hemispheres and the Corporation for Studies and Publications. Analyzes the structure, the general concepts, case law taken for development. Includes comments on the usefulness of this work for the study of competition law and the contribution to the lawyers who want to practice in this branch of economic law.

  9. Changes in forest productivity across Alaska consistent with biome shift.

    Science.gov (United States)

    Beck, Pieter S A; Juday, Glenn P; Alix, Claire; Barber, Valerie A; Winslow, Stephen E; Sousa, Emily E; Heiser, Patricia; Herriges, James D; Goetz, Scott J

    2011-04-01

    Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline. © 2011 Blackwell Publishing Ltd/CNRS.

  10. Shift Colors

    Science.gov (United States)

    Publications & News Shift Colors Pages default Sign In NPC Logo Banner : Shift Colors Search Navy Personnel Command > Reference Library > Publications & News > Shift Colors Top Link Bar Navy Personnel Library Expand Reference Library Quick Launch Shift Colors Shift Colors Archives Mailing Address How to

  11. Long-term trends of typhoon-induced rainfall over Taiwan: in situ evidence of poleward shift of typhoons in western North Pacific in recent decades

    Science.gov (United States)

    Liang, Ting-Yu; Oey, Leo; Huang, Shiming; Chou, Simon

    2017-04-01

    Tracks of tropical cyclones or typhoons in the western North Pacific have recently been shown to shift northward in the past several decades; the poleward shift has been attributed to the expansion of the tropics due to climate warming. Here we use 64-year, hourly rainfall observations around Taiwan, and take advantage of the unique terrain and geographic location of the island with respect to typhoon tracks, to show that since 1950 the typhoon-related rainfalls have been rising on the western side of the island, but decreasing on the eastern side. We show that these extraordinary rainfall patterns, despite the smallness of Taiwan, are indicative of a northward shift of typhoons related to the changes in the wind fields and surface warming over the Indian and Pacific tropical/subtropical regions.

  12. LONG-TERM TRENDS IN GROWTH OF PINUS PALUSTRIS AND PINUS ELLIOTTII GROWING ALONG A HYDROLOGICAL GRADIENT IN CENTRAL FLORIDA

    Science.gov (United States)

    Land-use change and urbanization has led to changes in the hydrologic regime in wet central Florida, with a trend toward lowered water table levels. These hydrologic changes are having environmental consequences in wetlands, where shifts in species composition and fire frequency...

  13. Shifts in the Antibiotic Susceptibility, Serogroups, and Clonal Complexes of Neisseria meningitidis in Shanghai, China: A Time Trend Analysis of the Pre-Quinolone and Quinolone Eras.

    Science.gov (United States)

    Chen, Mingliang; Guo, Qinglan; Wang, Ye; Zou, Ying; Wang, Gangyi; Zhang, Xi; Xu, Xiaogang; Zhao, Miao; Hu, Fupin; Qu, Di; Chen, Min; Wang, Minggui

    2015-06-01

    Fluoroquinolones have been used broadly since the end of the 1980s and have been recommended for Neisseria meningitidis prophylaxis since 2005 in China. The aim of this study was to determine whether and how N. meningitidis antimicrobial susceptibility, serogroup prevalence, and clonal complex (CC) prevalence shifted in association with the introduction and expanding use of quinolones in Shanghai, a region with a traditionally high incidence of invasive disease due to N. meningitidis. A total of 374 N. meningitidis isolates collected by the Shanghai Municipal Center for Disease Control and Prevention between 1965 and 2013 were studied. Shifts in the serogroups and CCs were observed, from predominantly serogroup A CC5 (84%) in 1965-1973 to serogroup A CC1 (58%) in 1974-1985, then to serogroup C or B CC4821 (62%) in 2005-2013. The rates of ciprofloxacin nonsusceptibility in N. meningitidis disease isolates increased from 0% in 1965-1985 to 84% (31/37) in 2005-2013 (p convenience isolates from 1965-1985 were available. The increasing prevalence of ciprofloxacin resistance since 2005 in Shanghai was associated with the spread of hypervirulent lineages CC4821 and CC5. Two resistant meningococcal clones ChinaCC4821-R1-C/B and ChinaCC5-R14-A have emerged in Shanghai during the quinolone era. Ciprofloxacin should be utilized with caution for the chemoprophylaxis of N. meningitidis in China.

  14. 100,000-year-long terrestrial record of millennial-scale linkage between eastern North American mid-latitude paleovegetation shifts and Greenland ice-core oxygen isotope trends

    Science.gov (United States)

    Litwin, Ronald J.; Smoot, Joseph P.; Pavich, Milan J.; Markewich, Helaine Walsh; Brook, George; Durika, Nancy J.

    2013-01-01

    We document frequent, rapid, strong, millennial-scale paleovegetation shifts throughout the late Pleistocene, within a 100,000+ yr interval (~ 115–15 ka) of terrestrial sediments from the mid-Atlantic Region (MAR) of North America. High-resolution analyses of fossil pollen from one core locality revealed a continuously shifting sequence of thermally dependent forest assemblages, ranging between two endmembers: subtropical oak-tupelo-bald cypress-gum forest and high boreal spruce-pine forest. Sedimentary textural evidence indicates fluvial, paludal, and loess deposition, and paleosol formation, representing sequential freshwater to subaerial environments in which this record was deposited. Its total age"depth model, based on radiocarbon and optically stimulated luminescence ages, ranges from terrestrial oxygen isotope stages (OIS) 6 to 1. The particular core sub-interval presented here is correlative in trend and timing to that portion of the oxygen isotope sequence common among several Greenland ice cores: interstades GI2 to GI24 (≈ OIS2–5 d). This site thus provides the first evidence for an essentially complete series of "Dansgaard"Oeschger" climate events in the MAR. These data reveal that the ~ 100,000 yr preceding the Late Glacial and Holocene in the MAR of North America were characterized by frequently and dynamically changing climate states, and by vegetation shifts that closely tracked the Greenland paleoclimate sequence.

  15. Quantized beam shifts in graphene

    Energy Technology Data Exchange (ETDEWEB)

    de Melo Kort-Kamp, Wilton Junior [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sinitsyn, Nikolai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dalvit, Diego Alejandro Roberto [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-08

    We predict the existence of quantized Imbert-Fedorov, Goos-Hanchen, and photonic spin Hall shifts for light beams impinging on a graphene-on-substrate system in an external magnetic field. In the quantum Hall regime the Imbert-Fedorov and photonic spin Hall shifts are quantized in integer multiples of the fine structure constant α, while the Goos-Hanchen ones in multiples of α2. We investigate the influence on these shifts of magnetic field, temperature, and material dispersion and dissipation. An experimental demonstration of quantized beam shifts could be achieved at terahertz frequencies for moderate values of the magnetic field.

  16. Shifts in the Antibiotic Susceptibility, Serogroups, and Clonal Complexes of Neisseria meningitidis in Shanghai, China: A Time Trend Analysis of the Pre-Quinolone and Quinolone Eras.

    Directory of Open Access Journals (Sweden)

    Mingliang Chen

    2015-06-01

    Full Text Available Fluoroquinolones have been used broadly since the end of the 1980s and have been recommended for Neisseria meningitidis prophylaxis since 2005 in China. The aim of this study was to determine whether and how N. meningitidis antimicrobial susceptibility, serogroup prevalence, and clonal complex (CC prevalence shifted in association with the introduction and expanding use of quinolones in Shanghai, a region with a traditionally high incidence of invasive disease due to N. meningitidis.A total of 374 N. meningitidis isolates collected by the Shanghai Municipal Center for Disease Control and Prevention between 1965 and 2013 were studied. Shifts in the serogroups and CCs were observed, from predominantly serogroup A CC5 (84% in 1965-1973 to serogroup A CC1 (58% in 1974-1985, then to serogroup C or B CC4821 (62% in 2005-2013. The rates of ciprofloxacin nonsusceptibility in N. meningitidis disease isolates increased from 0% in 1965-1985 to 84% (31/37 in 2005-2013 (p < 0.001. Among the ciprofloxacin-nonsusceptible isolates, 87% (27/31 were assigned to either CC4821 (n = 20 or CC5 (n = 7. The two predominant ciprofloxacin-resistant clones were designated ChinaCC4821-R1-C/B and ChinaCC5-R14-A. The ChinaCC4821-R1-C/B clone acquired ciprofloxacin resistance by a point mutation, and was present in 52% (16/31 of the ciprofloxacin-nonsusceptible disease isolates. The ChinaCC5-R14-A clone acquired ciprofloxacin resistance by horizontal gene transfer, and was found in 23% (7/31 of the ciprofloxacin-nonsusceptible disease isolates. The ciprofloxacin nonsusceptibility rate was 47% (7/15 among isolates from asymptomatic carriers, and nonsusceptibility was associated with diverse multi-locus sequence typing profiles and pulsed-field gel electrophoresis patterns. As detected after 2005, ciprofloxacin-nonsusceptible strains were shared between some of the patients and their close contacts. A limitation of this study is that isolates from 1986-2004 were not available

  17. Bidirectional soliton spectral tunneling effects in the regime of optical event horizon

    DEFF Research Database (Denmark)

    Gu, Jie; Guo, Hairun; Wang, Shaofei

    2015-01-01

    We study the cross-phase-modulation-induced soliton spectral shifting in the regime of the optical event horizon. The perturbed soliton to either red-shifting or blue-shifting is controllable, which could evoke bidirectional soliton spectral tunneling effects.......We study the cross-phase-modulation-induced soliton spectral shifting in the regime of the optical event horizon. The perturbed soliton to either red-shifting or blue-shifting is controllable, which could evoke bidirectional soliton spectral tunneling effects....

  18. Is the burden of overweight shifting to the poor across the globe? Time trends among women in 39 low- and middle-income countries (1991–2008)

    Science.gov (United States)

    Jones-Smith, Jessica C.; Gordon-Larsen, Penny; Siddiqi, Arjumand; Popkin, Barry M

    2012-01-01

    Background Overweight prevalence has increased globally; however, current time trends of overweight by social class in lower income countries are unknown. Methods We used repeated cross-sectional, nationally representative data from the Demographic and Health Surveys on women aged 18–49 with young children (n=421,689) in 39 lower income countries. We present overweight (body mass index ≥25) prevalence at each survey wave, prevalence difference and prevalence growth rate for each country over time is presented separately by wealth quintile and educational attainment. We present the correlation between nation wealth and differential overweight prevalence growth by wealth and education was estimated. Results In the majority of countries the highest wealth and education groups still have the highest prevalence of overweight and obesity. However, in a substantial number of countries (31% when wealth is used as the indicator of SES and 54% for education) the estimated increases in overweight prevalence over time have been greater in the lowest compared to the highest wealth and education groups. Gross Domestic Product per capita was associated with a higher overweight prevalence growth rate for the lowest wealth group compared to the highest (Pearson’s correlation coefficient: 0.45). Conclusions Higher (versus lower) wealth and education groups had higher overweight prevalence across most developing countries. However, some countries show a faster growth rates in overweight in the lowest (versus highest) wealth and education groups, indicative of an increasing burden of overweight among lower wealth and education groups in lower income countries. PMID:21912397

  19. Shifting the burden or expanding access to care? Assessing malaria trends following scale-up of community health worker malaria case management and reactive case detection.

    Science.gov (United States)

    Larsen, David A; Winters, Anna; Cheelo, Sanford; Hamainza, Busiku; Kamuliwo, Mulakwa; Miller, John M; Bridges, Daniel J

    2017-11-02

    Malaria is a significant burden to health systems and is responsible for a large proportion of outpatient cases at health facilities in endemic regions. The scale-up of community management of malaria and reactive case detection likely affect both malaria cases and outpatient attendance at health facilities. Using health management information data from 2012 to 2013 this article examines health trends before and after the training of volunteer community health workers to test and treat malaria cases in Southern Province, Zambia. An estimated 50% increase in monthly reported malaria infections was found when community health workers were involved with malaria testing and treating in the community (incidence rate ratio 1.52, p malaria testing and treating in the community. These results suggest a large public health benefit to both community case management of malaria and reactive case detection. First, the capacity of the malaria surveillance system to identify malaria infections was increased by nearly one-third. Second, the outpatient attendance at health facilities was modestly decreased. Expanding the capacity of the malaria surveillance programme through systems such as community case management and reactive case detection is an important step toward malaria elimination.

  20. Is the burden of overweight shifting to the poor across the globe? Time trends among women in 39 low- and middle-income countries (1991-2008).

    Science.gov (United States)

    Jones-Smith, J C; Gordon-Larsen, P; Siddiqi, A; Popkin, B M

    2012-08-01

    Overweight prevalence has increased globally; however, current time trends of overweight prevalence by social class in lower income countries have not been fully explored. We used repeated cross-sectional, nationally representative data from the Demographic and Health Surveys on women aged 18-49 years with young children (n=421,689) in 39 lower-income countries. We present overweight (body mass index ≥ 25 kg m⁻²) prevalence at each survey wave, prevalence difference and prevalence growth rate for each country over time, separately by wealth quintile and educational attainment. We present the correlation between nation wealth and differential overweight prevalence growth by wealth and education. In the majority of countries, the highest wealth and education groups still have the highest prevalence of overweight and obesity. However, in a substantial number of countries (14% when wealth is used as the indicator of socioeconomic status and 28% for education) the estimated increases in overweight prevalence over time have been greater in the lowest- compared with the highest-wealth and -education groups. Gross domestic product per capita was associated with a higher overweight prevalence growth rate for the lowest-wealth group compared with the highest (Pearson's correlation coefficient: 0.45). Higher (vs lower) wealth and education groups had higher overweight prevalence across most developing countries. However, some countries show a faster growth rate in overweight in the lowest- (vs highest-) wealth and -education groups, which is indicative of an increasing burden of overweight among lower wealth and education groups in the lower-income countries.

  1. Shifting Attention

    Science.gov (United States)

    Ingram, Jenni

    2014-01-01

    This article examines the shifts in attention and focus as one teacher introduces and explains an image that represents the processes involved in a numeric problem that his students have been working on. This paper takes a micro-analytic approach to examine how the focus of attention shifts through what the teacher and students do and say in the…

  2. Seasonal changes in the human alteration of fire regimes beyond the climate forcing

    Science.gov (United States)

    Fréjaville, Thibaut; Curt, Thomas

    2017-03-01

    Human activities have altered fire regimes for millennia by suppressing or enhancing natural fire activity. However, whether these anthropogenic pressures on fire activity have exceeded and will surpass climate forcing still remains uncertain. We tested if, how and the extent to which seasonal fire activity in southern France has recently (1976-2009) deviated from climate-expected trends. The latter were simulated using an ensemble of detrended fire-climate models. We found both seasonal and regional contrasts in climatic effects through a mixture of drought-driven and fuel-limited fire regimes. Dry contemporary conditions chiefly drove fire frequency and burned area, although higher fire activity was related to wetter conditions in the last three years. Surprisingly, the relative importance of preceding wet conditions was higher in winter than in summer, illustrating the strong potential dependency of regional fire-climate relationships on the human use and control of fires. In the Mediterranean mountains, warm winters and springs favour extensive fires in the following dry summer. These results highlight that increasing dryness with climate change could have antagonistic effects on fire regime by leading to larger fires in summer (moisture-limited), but lower fire activity in winter (fuel-limited fire regime). Furthermore, fire trends have significantly diverged from climatic expectations, with a strong negative alteration in fire activity in the Mediterranean lowlands and the summer burned area in the mountains. In contrast, alteration of winter fire frequency in the Mediterranean and Temperate mountains has shifted from positive to negative (or null) trends during the mid-1990s, a period when fire suppression policy underwent major revisions. Our findings demonstrate that changes in land-use and fire suppression policy have probably exceeded the strength of climate change effects on changing fire regime in southern Europe, making regional predictions of future

  3. Lava Fountaining Discharge Regime driven by Slug-to-Churn Flow Transition. (Invited)

    Science.gov (United States)

    Ripepe, M.; Pioli, L.; Marchetti, E.; Ulivieri, G.

    2013-12-01

    Lava fountaining episodes at Etna volcano appear characterized by the transition between Strombolian and Hawaiian end-member eruptive styles. There is no evidence for this transition in the seismic (i.e. seismic tremor) signal. However, infrasonic records provide unprecedented evidence on this flow transition. Each eruptive episode is characterized by distinctive common trend in the amplitude, waveform and frequency content of the infrasonic wavefield, which evidences the shift from discrete, and transient, strombolian to sustained, and oscillatory, lava fountain dynamics. Large scale experiments on the dynamics of two-phase flow of basaltic magmas show how the transition between different regimes mainly depends on gas volume flow, which in turn controls pressure distribution within the conduit and also magma vesicularity. In particular, while regular large bubble bursting is associated with slug flow regime, large amplitude and low frequency column oscillations are associated with churn flow. In large pipes, transition from slug to churn flow regime is independent on conduit diameter and it is reached at high superficial gas velocity. Lava fountaining episodes at Etna can be thus interpreted as induced by the transition from the slug (discrete strombolian) to churn flow (sustained lava fountain) regimes that is reflecting an increase in the gas discharge rate. Based on laboratory experiments, we calculate that transition between these two end-member explosive regimes at Etna occurs when gas superficial velocity is 76 m/s for near-the-vent stagnant magma conditions.

  4. DETERMINANTS OF FOREIGN DIRECT INVESTMENT IN NIGERIA: A MARKOV REGIME-SWITCHING APPROACH

    Directory of Open Access Journals (Sweden)

    Akinlo A. Enisan

    2017-04-01

    Full Text Available Several studies have analyzed the movement of foreign direct investment in Nigeria using linear approach. In contrast with all existing studies in Nigeria, this paper runs several non linear FDI equations where the main determinants of FDI are determined using Markov- Regime Switching Model (MSMs. The approach enables us to observe structural changes, where exist, in FDI equations through time. Asides, where FDI regression equation is truly nonlinear, MSMs fit data better than the linear models. The paper adopts maximum likelihood methodology of Markov-Regime Model (MSM to identify possible structural changes in level and/or trends and possible changes in parameters of independent variables through the transition probabilities. The results show that FDI process in Nigeria is governed by two different regimes and a shift from one regime to another regime depends on transition probabilities. The results show that the main determinants of FDI are GDP growth, macro instability, financial development, exchange rate, inflation and discount rate. This implies liberalization that stems inflation and enhance the value of domestic currency will attract more FDI into the country.

  5. Optimal dividend distribution under Markov regime switching

    NARCIS (Netherlands)

    Jiang, Z.; Pistorius, M.

    2012-01-01

    We investigate the problem of optimal dividend distribution for a company in the presence of regime shifts. We consider a company whose cumulative net revenues evolve as a Brownian motion with positive drift that is modulated by a finite state Markov chain, and model the discount rate as a

  6. The Two Regimes of Postwar Shipping

    DEFF Research Database (Denmark)

    Iversen, Martin Jes; Tenold, Stig

    2014-01-01

    the bargaining that accompanied the shift from the national regime to the competitive regime. Specifically, we show that the new regime primarily accommodated the interests of private actors such as shipping companies, rather than the interests of the authorities and the trade unions.......The aim of this article is to illustrate the most important changes in the regulatory framework of the shipping sector from the 1960s to 2010, and to analyse the basis for, and effects of, these changes. In order to explain how the transformation has occurred, we use two traditional maritime...... nations—Denmark and Norway—as case studies. First, we introduce the two regimes of Danish and Norwegian shipping: ‘the national regime’ from the early 1960s to the mid-1970s; and ‘the competitive regime’, which was fully established by the middle of the 1990s and still persists. Then, we briefly sketch...

  7. Abrupt climate-independent fire regime changes

    Science.gov (United States)

    Pausas, Juli G.; Keeley, Jon E.

    2014-01-01

    Wildfires have played a determining role in distribution, composition and structure of many ecosystems worldwide and climatic changes are widely considered to be a major driver of future fire regime changes. However, forecasting future climatic change induced impacts on fire regimes will require a clearer understanding of other drivers of abrupt fire regime changes. Here, we focus on evidence from different environmental and temporal settings of fire regimes changes that are not directly attributed to climatic changes. We review key cases of these abrupt fire regime changes at different spatial and temporal scales, including those directly driven (i) by fauna, (ii) by invasive plant species, and (iii) by socio-economic and policy changes. All these drivers might generate non-linear effects of landscape changes in fuel structure; that is, they generate fuel changes that can cross thresholds of landscape continuity, and thus drastically change fire activity. Although climatic changes might contribute to some of these changes, there are also many instances that are not primarily linked to climatic shifts. Understanding the mechanism driving fire regime changes should contribute to our ability to better assess future fire regimes.

  8. Market shifting

    Energy Technology Data Exchange (ETDEWEB)

    Forst, Michael

    2013-11-01

    After years of oversupply and artificially low module pricing, market analysts believe that the solar industry will begin to stabilize by 2017. While the market activities are shifting from Europe to the Asia Pacific region and the United States, the solar shakeout continues to be in full swing including solar cell and module manufacturing. (orig.)

  9. Tough Shift

    DEFF Research Database (Denmark)

    Brewer, Robert S.; Verdezoto, Nervo; Holst, Thomas

    2015-01-01

    people to change their behavior at home. Leveraging prior research on encouraging reductions in residential energy use through game play, we introduce ShareBuddy: a casual mobile game intended to encourage players not only to reduce, but also to shift their electricity use. We conducted two field studies...... real-world resource use into a game....

  10. Sustainable urban regime adjustments

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt; Jensen, Jens Stissing; Elle, Morten

    2013-01-01

    The endogenous agency that urban governments increasingly portray by making conscious and planned efforts to adjust the regimes they operate within is currently not well captured in transition studies. There is a need to acknowledge the ambiguity of regime enactment at the urban scale. This direc...

  11. Flux scaling: Ultimate regime

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Flux scaling: Ultimate regime. With the Nusselt number and the mixing length scales, we get the Nusselt number and Reynolds number (w'd/ν) scalings: and or. and. scaling expected to occur at extremely high Ra Rayleigh-Benard convection. Get the ultimate regime ...

  12. Exploring spatial-temporal dynamics of fire regime features in mainland Spain

    Science.gov (United States)

    Jiménez-Ruano, Adrián; Rodrigues Mimbrero, Marcos; de la Riva Fernández, Juan

    2017-10-01

    This paper explores spatial-temporal dynamics in fire regime features, such as fire frequency, burnt area, large fires and natural- and human-caused fires, as an essential part of fire regime characterization. Changes in fire features are analysed at different spatial - regional and provincial/NUTS3 - levels, together with summer and winter temporal scales, using historical fire data from Spain for the period 1974-2013. Temporal shifts in fire features are investigated by means of change point detection procedures - Pettitt test, AMOC (at most one change), PELT (pruned exact linear time) and BinSeg (binary segmentation) - at a regional level to identify changes in the time series of the features. A trend analysis was conducted using the Mann-Kendall and Sen's slope tests at both the regional and NUTS3 level. Finally, we applied a principal component analysis (PCA) and varimax rotation to trend outputs - mainly Sen's slope values - to summarize overall temporal behaviour and to explore potential links in the evolution of fire features. Our results suggest that most fire features show remarkable shifts between the late 1980s and the first half of the 1990s. Mann-Kendall outputs revealed negative trends in the Mediterranean region. Results from Sen's slope suggest high spatial and intra-annual variability across the study area. Fire activity related to human sources seems to be experiencing an overall decrease in the northwestern provinces, particularly pronounced during summer. Similarly, the Hinterland and the Mediterranean coast are gradually becoming less fire affected. Finally, PCA enabled trends to be synthesized into four main components: winter fire frequency (PC1), summer burnt area (PC2), large fires (PC3) and natural fires (PC4).

  13. Exploring spatial–temporal dynamics of fire regime features in mainland Spain

    Directory of Open Access Journals (Sweden)

    A. Jiménez-Ruano

    2017-10-01

    Full Text Available This paper explores spatial–temporal dynamics in fire regime features, such as fire frequency, burnt area, large fires and natural- and human-caused fires, as an essential part of fire regime characterization. Changes in fire features are analysed at different spatial – regional and provincial/NUTS3 – levels, together with summer and winter temporal scales, using historical fire data from Spain for the period 1974–2013. Temporal shifts in fire features are investigated by means of change point detection procedures – Pettitt test, AMOC (at most one change, PELT (pruned exact linear time and BinSeg (binary segmentation – at a regional level to identify changes in the time series of the features. A trend analysis was conducted using the Mann–Kendall and Sen's slope tests at both the regional and NUTS3 level. Finally, we applied a principal component analysis (PCA and varimax rotation to trend outputs – mainly Sen's slope values – to summarize overall temporal behaviour and to explore potential links in the evolution of fire features. Our results suggest that most fire features show remarkable shifts between the late 1980s and the first half of the 1990s. Mann–Kendall outputs revealed negative trends in the Mediterranean region. Results from Sen's slope suggest high spatial and intra-annual variability across the study area. Fire activity related to human sources seems to be experiencing an overall decrease in the northwestern provinces, particularly pronounced during summer. Similarly, the Hinterland and the Mediterranean coast are gradually becoming less fire affected. Finally, PCA enabled trends to be synthesized into four main components: winter fire frequency (PC1, summer burnt area (PC2, large fires (PC3 and natural fires (PC4.

  14. What is the New Chinese Currency Regime?

    OpenAIRE

    Shah, Ajay; Zeileis, Achim; Patnaik, Ila

    2005-01-01

    The revaluation of the yuan in July 2005 was described by the Chinese central bank as a change in the currency regime, rather than merely a changed level of the exchange rate. The reform was said to involve a shift away from the fixed exchange rate, a gradual movement towards greater flexibility, and a peg to a basket of currencies. This paper closely examines the post-July Chinese currency regime utilising contemporary ideas in the econometrics of structural change. We find that the yuan has...

  15. Forecasting inflation with gradual regime shifts and exogenous information

    DEFF Research Database (Denmark)

    González, Andrés; Hubrich, Kirstin; Teräsvirta, Timo

    to be forecast to form a single inflation forecast. We show, both theoretically and by simulations, how this is done by using the penalised likelihood in the estimation of model parameters. In forecasting inflation, the central bank inflation target, if it exists, is a natural example of such prior information...

  16. Oceanographic regime shift during 1997 in Disko Bay, Western Greenland

    DEFF Research Database (Denmark)

    Hansen, Marc Overgaard; Nielsen, Torkel Gissel; Stedmon, Colin A.

    2012-01-01

    conditions, while the deeper water strata were more stable and were primarily influenced by large-scale circulation patterns. There was a marked increase in the average water temperatures at 200-m depth in spring 1997, with the long-term average increasing from 1.30uC to 2.25uC. Weekly data from 1996 to 1997...

  17. Avoiding an ecological regime shift is sound economic policy

    NARCIS (Netherlands)

    Heijnen, P.; Wagener, F.O.O.

    2013-01-01

    We extend the shallow lake model by adding the capital stock of an industry. A government can mitigate the effects of pollution arising from industrial activities by imposing the requirement to abate emissions. Within this framework two scenarios are examined: in the social optimal benchmark, the

  18. Avoiding an ecological regime shift is sound economic policy

    NARCIS (Netherlands)

    Heijnen, P.; Wagener, F. O. O.

    We extend the shallow lake model by adding the capital stock of an industry. A government can mitigate the effects of pollution arising from industrial activities by imposing the requirement to abate emissions. Within this framework two scenarios are examined: in the social optimal benchmark, the

  19. Fluid Shifts

    Science.gov (United States)

    Stenger, M. B.; Hargens, A. R.; Dulchavsky, S. A.; Arbeille, P.; Danielson, R. W.; Ebert, D. J.; Garcia, K. M.; Johnston, S. L.; Laurie, S. S.; Lee, S. M. C.; hide

    2017-01-01

    Introduction. NASA's Human Research Program is focused on addressing health risks associated with long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but now more than 50 percent of ISS astronauts have experienced more profound, chronic changes with objective structural findings such as optic disc edema, globe flattening and choroidal folds. These structural and functional changes are referred to as the visual impairment and intracranial pressure (VIIP) syndrome. Development of VIIP symptoms may be related to elevated intracranial pressure (ICP) secondary to spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to determine if a relation exists with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as any VIIP-related effects of those shifts, are predicted by the crewmember's pre-flight status and responses to acute hemodynamic manipulations, specifically posture changes and lower body negative pressure. Methods. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, and calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid

  20. Experimental study of steam condensation regime map for simplified spargers

    International Nuclear Information System (INIS)

    Kim, Y. S.; Yoon, Y. J.; Song, C. H.; Park, C. K.; Kang, H. S.; Jun, H. K.

    2003-01-01

    An experimental study was conducted to produce a condensation regime map for single-hole and 4-hole steam spargers using GIRLS facility. The regime map for a single-hole sparger was derived using parameters such as the frequency and magnitude of the dynamic pressure. For 4-hole sparager, the regime map was derived using the trends of sound and dynamic pressure. Using the single-hole and 4-hole data, a steam jet condensation regime map was suggested with respect to pool temperature and steam mass flux

  1. 'CANDLE' burnup regime after LWR regime

    International Nuclear Information System (INIS)

    Sekimoto, Hiroshi; Nagata, Akito

    2008-01-01

    CANDLE (Constant Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy producing reactor) burnup strategy can derive many merits. From safety point of view, the change of excess reactivity along burnup is theoretically zero, and the core characteristics, such as power feedback coefficients and power peaking factor, are not changed along burnup. Application of this burnup strategy to neutron rich fast reactors makes excellent performances. Only natural or depleted uranium is required for the replacing fuels. About 40% of natural or depleted uranium undergoes fission without the conventional reprocessing and enrichment. If the LWR produced energy of X Joules, the CANDLE reactor can produce about 50X Joules from the depleted uranium left at the enrichment facility for the LWR fuel. If we can say LWRs have produced energy sufficient for full 20 years, we can produce the energy for 1000 years by using the CANDLE reactors with depleted uranium. We need not mine any uranium ore, and do not need reprocessing facility. The burnup of spent fuel becomes 10 times. Therefore, the spent fuel amount per produced energy is also reduced to one-tenth. The details of the scenario of CANDLE burnup regime after LWR regime will be presented at the symposium. (author)

  2. Leisure in transformation: Meta-trends changing the world | Edginton ...

    African Journals Online (AJOL)

    Meta-trends often arise from underlying shifts in social, cultural, political, ... discussed the impact of several key meta-trends on leisure, quality of life and community ... changes and shifts; 2) social media, technology and universal connectivity; ...

  3. Arctic circulation regimes.

    Science.gov (United States)

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L

    2015-10-13

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. © 2015 The Authors.

  4. THE INFLUENCED FLOW REGIMES

    Directory of Open Access Journals (Sweden)

    Gavril PANDI

    2011-03-01

    Full Text Available The influenced flow regimes. The presence and activities ofhumanity influences the uniform environmental system, and in this context, therivers water resources. In concordance with this, the natural runoff regime suffersbigger and deeper changes. The nature of these changes depending on the type anddegree of water uses. The multitude of the use cause different types of influence,whit different quantitative aspects. In the same time, the influences havequalitative connotations, too, regarding to the modifications of the yearly watervolume runoff. So the natural runoff regime is modified. After analyzing thedistribution laws of the monthly runoff, there have been differenced four types ofinfluenced runoff regimes. In the excess type the influenced runoff is bigger thanthe natural, continuously in the whole year. The deficient type is characterized byinverse rapports like the first type, in the whole year. In the sinusoidal type, theinfluenced runoff is smaller than the natural in the period when the water isretained in the lake reservoirs, and in the depletion period the situation inverts. Atthe irregular type the ratio between influenced and natural runoff is changeable ina random meaner monthly. The recognition of the influenced regime and the gradeof influence are necessary in the evaluation and analysis of the usable hydrologicalriver resources, in the flood defence activities, in the complex scheme of thehydrographic basins, in the environment design and so on.

  5. Supply regimes in fisheries

    DEFF Research Database (Denmark)

    Nielsen, Max

    2006-01-01

    Supply in fisheries is traditionally known for its backward bending nature, owing to externalities in production. Such a supply regime, however, exist only for pure open access fisheries. Since most fisheries worldwide are neither pure open access, nor optimally managed, rather between the extremes......, the traditional understanding of supply regimes in fisheries needs modification. This paper identifies through a case study of the East Baltic cod fishery supply regimes in fisheries, taking alternative fisheries management schemes and mesh size limitations into account. An age-structured Beverton-Holt based bio......-economic supply model with mesh sizes is developed. It is found that in the presence of realistic management schemes, the supply curves are close to vertical in the relevant range. Also, the supply curve under open access with mesh size limitations is almost vertical in the relevant range, owing to constant...

  6. Shifting Sugars and Shifting Paradigms

    Science.gov (United States)

    Siegal, Mark L.

    2015-01-01

    No organism lives in a constant environment. Based on classical studies in molecular biology, many have viewed microbes as following strict rules for shifting their metabolic activities when prevailing conditions change. For example, students learn that the bacterium Escherichia coli makes proteins for digesting lactose only when lactose is available and glucose, a better sugar, is not. However, recent studies, including three PLOS Biology papers examining sugar utilization in the budding yeast Saccharomyces cerevisiae, show that considerable heterogeneity in response to complex environments exists within and between populations. These results join similar recent results in other organisms that suggest that microbial populations anticipate predictable environmental changes and hedge their bets against unpredictable ones. The classical view therefore represents but one special case in a range of evolutionary adaptations to environmental changes that all organisms face. PMID:25688600

  7. Shifting sugars and shifting paradigms.

    Directory of Open Access Journals (Sweden)

    Mark L Siegal

    2015-02-01

    Full Text Available No organism lives in a constant environment. Based on classical studies in molecular biology, many have viewed microbes as following strict rules for shifting their metabolic activities when prevailing conditions change. For example, students learn that the bacterium Escherichia coli makes proteins for digesting lactose only when lactose is available and glucose, a better sugar, is not. However, recent studies, including three PLOS Biology papers examining sugar utilization in the budding yeast Saccharomyces cerevisiae, show that considerable heterogeneity in response to complex environments exists within and between populations. These results join similar recent results in other organisms that suggest that microbial populations anticipate predictable environmental changes and hedge their bets against unpredictable ones. The classical view therefore represents but one special case in a range of evolutionary adaptations to environmental changes that all organisms face.

  8. Cargo liability regimes

    Science.gov (United States)

    2001-01-01

    There are at present at least three international regimes of maritime cargo liability in force in different countries of the world - the original Hague rules (1924), the updated version known as the Hague-Visby rules (1968, further amended 1979), and...

  9. Trust in regulatory regimes

    NARCIS (Netherlands)

    Six, Frédérique; Verhoest, Koen

    2017-01-01

    Within political and administrative sciences generally, trust as a concept is contested, especially in the field of regulatory governance. This groundbreaking book is the first to systematically explore the role and dynamics of trust within regulatory regimes. Conceptualizing, mapping and analyzing

  10. East Asian welfare regime

    DEFF Research Database (Denmark)

    Abrahamson, Peter

    2017-01-01

    The paper asks if East Asian welfare regimes are still productivist and Confucian? And, have they developed public care policies? The literature is split on the first question but (mostly) confirmative on the second. Care has to a large, but insufficient extent, been rolled out in the region...

  11. Governance regime and location influence avoided deforestation success of protected areas in the Brazilian Amazon.

    Science.gov (United States)

    Nolte, Christoph; Agrawal, Arun; Silvius, Kirsten M; Soares-Filho, Britaldo S

    2013-03-26

    Protected areas in tropical countries are managed under different governance regimes, the relative effectiveness of which in avoiding deforestation has been the subject of recent debates. Participants in these debates answer appeals for more strict protection with the argument that sustainable use areas and indigenous lands can balance deforestation pressures by leveraging local support to create and enforce protective regulations. Which protection strategy is more effective can also depend on (i) the level of deforestation pressures to which an area is exposed and (ii) the intensity of government enforcement. We examine this relationship empirically, using data from 292 protected areas in the Brazilian Amazon. We show that, for any given level of deforestation pressure, strictly protected areas consistently avoided more deforestation than sustainable use areas. Indigenous lands were particularly effective at avoiding deforestation in locations with high deforestation pressure. Findings were stable across two time periods featuring major shifts in the intensity of government enforcement. We also observed shifting trends in the location of protected areas, documenting that between 2000 and 2005 strictly protected areas were more likely to be established in high-pressure locations than in sustainable use areas and indigenous lands. Our findings confirm that all protection regimes helped reduce deforestation in the Brazilian Amazon.

  12. International Food Regime

    Directory of Open Access Journals (Sweden)

    A. V. Malov

    2018-01-01

    Full Text Available The review article reveals the content of the concept of Food Regime, which is little-known in the Russian academic reference. The author monitored and codified the semantic dynamic of the terminological unit from its original interpretations to modern formulations based on the retrospective analysis. The rehabilitation of the academic merits of D. Puchala and R. Hopkins — authors who used the concept Food Regime for a few years before its universally recognized origin and official scientific debut, was accomplished with help of historical and comparative methods. The author implemented the method of ascension from the abstract to the concrete to demonstrating the classification of Food Regimes compiled on the basis of geopolitical interests in the sphere of international production, consumption, and distribution of foodstuffs. The characteristic features of historically formed Food Regime were described in the chronological order, as well as modern tendencies possessing reformist potential were identified. In particular, it has been established that the idea of Food Sovereignty (which is an alternative to the modern Corporate Food Regime is the subject for acute academic disputes. The discussion between P. McMichael P. and H. Bernstein devoted to the “peasant question” — mobilization frame of the Food Sovereignty strategy was analyzed using the secondary data processing method. Due to the critical analysis, the author comes to the conclusion that it is necessary to follow the principles of the Food Sovereignty strategy to prevent the catastrophic prospects associated with ecosystem degradation, accelerated erosion of soils, the complete disappearance of biodiversity and corporate autoc racy successfully. The author is convinced that the idea of Food Sovereignty can ward off energetic liberalization of nature, intensive privatization of life and rapid monetization of unconditioned human reflexes.

  13. Dynamic Effect of a Change in the Exchange Rate System: From a Fixed Regime to a Basket-Peg or a Floating Regime

    OpenAIRE

    Yoshino, Naoyuki; Kaji, Sahoko; Asonuma, Tamon

    2015-01-01

    This paper theoretically evaluates the dynamic effects of a shift in an exchange rate system from a fixed regime to a basket peg, or to a floating regime, and obtains transition paths for the shift based on a dynamic stochastic general equilibrium model of a small open economy. We apply quantitative analysis using data from the People's Republic of China and Thailand and find that a small open country would be better off shifting to a basket peg or to a floating regime than maintaining a doll...

  14. Travel and tourism trends

    Science.gov (United States)

    Deborah J. Chavez

    1995-01-01

    Demographic trends which impact leisure time activities are highlighted, with particular emphasis given to the impacts of the growth of minority populations. Data was collected from recreationists to National Forests and from residents of an urban community. The data indicate a shift in outdoor recreation activities.

  15. Floating Exchange Rate Regime

    OpenAIRE

    Quader, Syed Manzur

    2004-01-01

    In recent years, many developing countries having a history of high inflation, unfavorable balance of payment situation and a high level of foreign currencies denominated debt, have switched or are in the process of switching to a more flexible exchange rate regime. Therefore, the stability of the exchange rate and the dynamics of its volatility are more crucial than before to prevent financial crises and macroeconomic disturbances. This paper is designed to find out the reasons behind Bangla...

  16. Water regime of steam power plants

    International Nuclear Information System (INIS)

    Oesz, Janos

    2011-01-01

    The water regime of water-steam thermal power plants (secondary side of pressurized water reactors (PWR); fossil-fired thermal power plants - referred to as steam power plants) has changed in the past 30 years, due to a shift from water chemistry to water regime approach. The article summarizes measures (that have been realised by chemists of NPP Paks) on which the secondary side of NPP Paks has become a high purity water-steam power plant and by which the water chemistry stress corrosion risk of heat transfer tubes in the VVER-440 steam generators was minimized. The measures can also be applied to the water regime of fossil-fired thermal power plants with super- and subcritical steam pressure. Based on the reliability analogue of PWR steam generators, water regime can be defined as the harmony of construction, material(s) and water chemistry, which needs to be provided in not only the steam generators (boiler) but in each heat exchanger of steam power plant: - Construction determines the processes of flow, heat and mass transfer and their local inequalities; - Material(s) determines the minimal rate of general corrosion and the sensitivity for local corrosion damage; - Water chemistry influences the general corrosion of material(s) and the corrosion products transport, as well as the formation of local corrosion environment. (orig.)

  17. Infrasound reveals transition to oscillatory discharge regime during lava fountaining: Implication for early warning

    Science.gov (United States)

    Ulivieri, Giacomo; Ripepe, Maurizio; Marchetti, Emanuele

    2013-06-01

    present the analysis of ~4 million infrasonic signals which include 39 episodes of lava fountains recorded at 5.5 km from the active vents. We show that each eruptive episode is characterized by a distinctive trend in the amplitude, waveform, and frequency content of the acoustic signals, reflecting different explosive levels. Lava fountain starts with an ~93 min long violent phase of acoustic transients at ~1.25 Hz repeating every 2-5 s. Infrasound suddenly evolves into a persistent low-frequency quasi-monochromatic pressure oscillation at ~0.4 Hz. We interpret this shift as induced by the transition from the slug (discrete Strombolian) to churn flow (sustained lava fountain) regime that is reflecting an increase in the gas discharge rate. We calculate that infrasonic transition can occur at a gas superficial velocity of ≤76 m/s and it can be used to define infrasonic-based thresholds for an efficient early warning system.

  18. The shifting beverage landscape.

    Science.gov (United States)

    Storey, Maureen

    2010-04-26

    STOREY, M.L. The shifting beverage landscape. PHYSIOL BEHAV, 2010. - Simultaneous lifestyle changes have occurred in the last few decades, creating an imbalance in energy intake and energy expenditure that has led to overweight and obesity. Trends in the food supply show that total daily calories available per capita increased 28% since 1970. Total energy intake among men and women has also increased dramatically since that time. Some have suggested that intake of beverages has had a disproportional impact on obesity. Data collected by the Beverage Marketing Corporation between 1988-2008 demonstrate that, in reality, fewer calories per ounce are being produced by the beverage industry. Moreover, data from the National Cancer Institute show that soft drink intake represents 5.5% of daily calories. Data from NHANES 1999-2003 vs. 2003-06 may demonstrate a shift in beverage consumption for age/gender groups, ages 6 to>60years. The beverages provided in schools have significantly changed since 2006 when the beverage industry implemented School Beverage Guidelines. This voluntary action has removed full-calorie soft drinks from participating schools across the country. This shift to lower-calorie and smaller-portion beverages in school has led to a significant decrease in total beverage calories in schools. These data support the concept that to prevent and treat obesity, public health efforts should focus on energy balance and that a narrow focus on sweetened beverages is unlikely to have any meaningful impact on this complex problem. Copyright 2010 Elsevier Inc. All rights reserved.

  19. H-mode regimes and observators of central toroidal rotation in Alcator C-Mod

    International Nuclear Information System (INIS)

    Greenwald, M.; Rice, J.; Boivin, R.

    1999-01-01

    The Enhanced D α or EDA H-mode regime in Alcator C-Mod has been investigated and compared in detail to ELM-free plasmas. (In this paper, ELM-free will refer to discharges with no type I ELMs and with no sign of EDA, though technically, most EDA plasmas are ELM-free as well.) EDA discharges have only slightly lower energy confinement than comparable ELM-free ones, but show markedly reduced impurity confinement. Thus EDA discharges do not accumulate impurities and typically have a lower fraction of radiated power. EDA plasmas are seen to be more likely at low plasma current (q > 3.7 - 4), for moderate plasma shaping (0.35 - 0.55), and for high neutral pressures. No obvious trends were observed with input power or pressure (β). In both H-mode regimes, and in ICRF heated L-modes, central impurity toroidal rotation has been deduced, from the Doppler shifts of argon x-ray lines. Rotation velocities up to 1.3 x 10 5 m/s in the co-current direction have been observed in H-mode discharges that had no direct momentum input. There is a strong correlation between the increase in the central impurity rotation velocity and the increase in the plasma stored energy, induced by ICRF heating. In otherwise similar discharges with the same stored energy increase, plasmas with lower current rotate faster. The ion pressure gradient is an unimportant contributor to the central impurity rotation and the presence of a substantial core radial electric field is inferred during the ICRF pulse. An inward shift of ions induced by ICRF waves could give rise to a non-ambipolar electric field in the plasma core. Comparisons with a neo-classical ion orbit shift model show good agreement with the observations, both in magnitude, and in the scaling with plasma current. (author)

  20. Regime-switching models to study psychological process

    NARCIS (Netherlands)

    Hamaker, E.L.; Grasman, R.P.P.P.; Kamphuis, J.H.

    2010-01-01

    Many psychological processes are characterized by recurrent shifts between different states. To model these processes at the level of the individual, regime-switching models may prove useful. In this chapter we discuss two of these models: the threshold autoregressive model and the Markov

  1. Characteristics of regulatory regimes

    Directory of Open Access Journals (Sweden)

    Noralv Veggeland

    2013-03-01

    Full Text Available The overarching theme of this paper is institutional analysis of basic characteristics of regulatory regimes. The concepts of path dependence and administrative traditions are used throughout. Self-reinforcing or positive feedback processes in political systems represent a basic framework. The empirical point of departure is the EU public procurement directive linked to OECD data concerning use of outsourcing among member states. The question is asked: What has caused the Nordic countries, traditionally not belonging to the Anglo-Saxon market-centred administrative tradition, to be placed so high on the ranking as users of the Market-Type Mechanism (MTM of outsourcing in the public sector vs. in-house provision of services? A thesis is that the reason may be complex, but might be found in an innovative Scandinavian regulatory approach rooted in the Nordic model.

  2. Regime switching state-space models applied to psychological processes: handling missing data and making inferences

    NARCIS (Netherlands)

    Hamaker, E.L.; Grasman, R.P.P.P.

    2012-01-01

    Many psychological processes are characterized by recurrent shifts between distinct regimes or states. Examples that are considered in this paper are the switches between different states associated with premenstrual syndrome, hourly fluctuations in affect during a major depressive episode, and

  3. Crustal stress regime in Italy

    Directory of Open Access Journals (Sweden)

    M. Cesaro

    1997-06-01

    Full Text Available In order to obtain a reliable map of the present-day stress field in Italy, needed to better understand the active tectonic processes and to contribute to the assessment of seismic hazard, in 1992 we started to collect and analyze new data from borehole breakouts in deep oil and geothermal wells and focal mechanisms of earthquakes (2.5 < M <5 occurred in Italy between 1988 and 1995. From about 200 deep wells and 300 focal mechanisms analyzed to date, we infer that: the internal (SW sector of the Northern Apenninic arc is extending with minimum compressional stress (Shmin oriented ? ENE, while the external front is thrusting over the Adriatic foreland (Shmin ? NW-SE. The entire Southern Apennine is extending in NE direction (from the Tyrrhenian margin to the Apulian foreland and compression (in the foredeep is no longer active at the outer (NE thrust front. Between these two arcs, an abrupt change in the tectonic regime is detected with directions of horizontal stress changing by as much as 90º in the external front, around latitude 430N. Along the Ionian side of the Calabrian arc the stress directions inferred from breakouts and focal mechanisms are scattered with a hint of rotation from N-S Shmin close to the Southern Apennines, to ~ E-W directions in the Messina Strait. In Sicily, a NW-SE direction of SHmax is evident in the Hyblean foreland, parallel to the direction of plate motion between Africa and Europe. A more complex pattern of stress directions is observed in the thrust belt zone, with rotations from the regional trend (NW í directed SHmax to NE oriented SHmax. A predominant NW direction of SHmax is also detected in mainland Sicily from earthquake focal mechanisms, but no well data are available in this region. In the northern part of Sicily (Aeolian Islands a ~N-S direction of SHmax is observed.

  4. A Study on the cooperation policy in multilateral nuclear control regimes and the advancing of national export control system

    International Nuclear Information System (INIS)

    Lee, Byung Wook; Oh, K. B.; Yang, M. H.; Lee, H. M.; Lee, K. S.; Ko, H. S.; Ryu, J. S.; Kim, J. S.

    2004-08-01

    This study carried out the analysis of trends of the multilateral nuclear control in four aspects. First, this study analyzes the past trends of the international nuclear non-proliferation regime, which includes the NPT, the IAEA safeguards system, the international nuclear export control regime and the physical protection of nuclear materials. Second, this study establishes the multilateral cooperation strategies for the effective cooperation in the process of strengthening the nuclear control regimes. Third, this study reviews the major agenda of nuclear control regimes and establishes national positions on each agenda. Fourth, this study also analyzes outstanding issues in nuclear control regimes and derives some factors to reflect national nuclear control system

  5. Market Suitability and Performance Tradeoffs Offered by Commercial Wind Turbines across Differing Wind Regimes

    Directory of Open Access Journals (Sweden)

    Souma Chowdhury

    2016-05-01

    Full Text Available The suitability of turbine configurations to different wind resources has been traditionally restricted to considering turbines operating as standalone entities. In this paper, a framework is thus developed to investigate turbine suitability in terms of the minimum cost of energy offered when operating as a group of optimally-micro-sited turbines. The four major steps include: (i characterizing the geographical variation of wind regimes in the onshore U.S. market; (ii determining the best performing turbines for different wind regimes through wind farm layout optimization; (iii developing a metric to quantify the expected market suitability of available turbine configurations; and (iv exploring the best tradeoffs between the cost and capacity factor yielded by these turbines. One hundred thirty one types of commercial turbines offered by major global manufacturers in 2012 are considered for selection. It is found that, in general, higher rated power turbines with medium tower heights are the most favored. Interestingly, further analysis showed that “rotor diameter/hub height” ratios greater than 1.1 are the least attractive for any of the wind classes. It is also observed that although the “cost-capacity factor” tradeoff curve expectedly shifted towards higher capacity factors with increasing wind class, the trend of the tradeoff curve remained practically similar.

  6. Perspectives on the International and Internal Nuclear Security Regime

    International Nuclear Information System (INIS)

    Jang, Sung Soon

    2015-01-01

    The term, 'Nuclear Security' became more familiar to Korean public after the government hosted 2012 Seoul Nuclear Security Summit. Nuclear Security is prevention of, detection of and response to criminal or intentional unauthorized acts involving or directed at nuclear material, other radioactive material, associated facilities, or associated activities. Nuclear Security includes physical protection, security of radioactive sources, nuclear forensics, nuclear smuggling prevention, border monitoring, and cyber security with regard to nuclear and other radiological materials. This abstract will review recent international trends and discuss the nuclear security regime in the Republic of Korea (ROK). The international Nuclear Security Regime has been strengthened. The upcoming Chicago Summit in 2016 and the entry into force of the Amendment of Convention on Physical Protection of Nuclear Materials (CPPNM) will bring major changes in nuclear security. The Republic of Korea hosted the 2012 Seoul Summit and strengthened domestic regime to meet international standards. The ROK has worked hard to contribute to the international security regime and to establish a robust domestic security regime against terrorist threats. Even if the nuclear security regime is robust, Risk-informed Nuclear Security management should be established to meet international standards and to implement effective as well as an efficient nuclear security regime

  7. Perspectives on the International and Internal Nuclear Security Regime

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Sung Soon [Korea Nuclear Non-proliferation and Control, Daejeon (Korea, Republic of)

    2015-10-15

    The term, 'Nuclear Security' became more familiar to Korean public after the government hosted 2012 Seoul Nuclear Security Summit. Nuclear Security is prevention of, detection of and response to criminal or intentional unauthorized acts involving or directed at nuclear material, other radioactive material, associated facilities, or associated activities. Nuclear Security includes physical protection, security of radioactive sources, nuclear forensics, nuclear smuggling prevention, border monitoring, and cyber security with regard to nuclear and other radiological materials. This abstract will review recent international trends and discuss the nuclear security regime in the Republic of Korea (ROK). The international Nuclear Security Regime has been strengthened. The upcoming Chicago Summit in 2016 and the entry into force of the Amendment of Convention on Physical Protection of Nuclear Materials (CPPNM) will bring major changes in nuclear security. The Republic of Korea hosted the 2012 Seoul Summit and strengthened domestic regime to meet international standards. The ROK has worked hard to contribute to the international security regime and to establish a robust domestic security regime against terrorist threats. Even if the nuclear security regime is robust, Risk-informed Nuclear Security management should be established to meet international standards and to implement effective as well as an efficient nuclear security regime.

  8. Energy efficiency improvement by gear shifting optimization

    Directory of Open Access Journals (Sweden)

    Blagojevic Ivan A.

    2013-01-01

    Full Text Available Many studies have proved that elements of driver’s behavior related to gear selection have considerable influence on the fuel consumption. Optimal gear shifting is a complex task, especially for inexperienced drivers. This paper presents an implemented idea for gear shifting optimization with the aim of fuel consumption minimization with more efficient engine working regimes. Optimized gear shifting enables the best possible relation between vehicle motion regimes and engine working regimes. New theoretical-experimental approach has been developed using On-Board Diagnostic technology which so far has not been used for this purpose. The matrix of driving modes according to which tests were performed is obtained and special data acquisition system and analysis process have been developed. Functional relations between experimental test modes and adequate engine working parameters have been obtained and all necessary operations have been conducted to enable their use as inputs for the designed algorithm. The created Model has been tested in real exploitation conditions on passenger car with Otto fuel injection engine and On-Board Diagnostic connection without any changes on it. The conducted tests have shown that the presented Model has significantly positive effects on fuel consumption which is an important ecological aspect. Further development and testing of the Model allows implementation in wide range of motor vehicles with various types of internal combustion engines.

  9. Trend analysis

    International Nuclear Information System (INIS)

    Smith, M.; Jones, D.R.

    1991-01-01

    The goal of exploration is to find reserves that will earn an adequate rate of return on the capital invested. Neither exploration nor economics is an exact science. The authors must therefore explore in those trends (plays) that have the highest probability of achieving this goal. Trend analysis is a technique for organizing the available data to make these strategic exploration decisions objectively and is in conformance with their goals and risk attitudes. Trend analysis differs from resource estimation in its purpose. It seeks to determine the probability of economic success for an exploration program, not the ultimate results of the total industry effort. Thus the recent past is assumed to be the best estimate of the exploration probabilities for the near future. This information is combined with economic forecasts. The computer software tools necessary for trend analysis are (1) Information data base - requirements and sources. (2) Data conditioning program - assignment to trends, correction of errors, and conversion into usable form. (3) Statistical processing program - calculation of probability of success and discovery size probability distribution. (4) Analytical processing - Monte Carlo simulation to develop the probability distribution of the economic return/investment ratio for a trend. Limited capital (short-run) effects are analyzed using the Gambler's Ruin concept in the Monte Carlo simulation and by a short-cut method. Multiple trend analysis is concerned with comparing and ranking trends, allocating funds among acceptable trends, and characterizing program risk by using risk profiles. In summary, trend analysis is a reality check for long-range exploration planning

  10. Micropatch Antenna Phase Shifting

    National Research Council Canada - National Science Library

    Thursby, Michael

    2000-01-01

    .... We have been looking at the ability of embedded element to adjust the phase shift seen by the element with the goal of being able to remove the phase shifting devices from the antenna and replace...

  11. Micropatch Antenna Phase Shifting

    National Research Council Canada - National Science Library

    Thursby, Michael

    1999-01-01

    .... We have been looking at the ability of embedded element to adjust the phase shift seen by the element wit the goal of being able to remove the phase shifting devices from the antenna and replace...

  12. OpenShift Workshop

    CERN Multimedia

    CERN. Geneva; Rodriguez Peon, Alberto

    2017-01-01

    Workshop to introduce developers to the OpenShift platform available at CERN. Several use cases will be shown, including deploying an existing application into OpenShift. We expect attendees to realize about OpenShift features and general architecture of the service.

  13. Critical Review--Outsourcing: A Paradigm Shift.

    Science.gov (United States)

    Kakabadse, Nada; Kakabadse, Andrew

    2000-01-01

    Discusses trends in outsourcing, provision of goods and services to an organization that were previously delivered in house. Addresses outsourcing in the public sector, advantages and disadvantages, implications for human resource development, and the shift to the new "psychological contract" between employers and employees. (Contains…

  14. Effectiveness of the Twelve-Hour Shift.

    Science.gov (United States)

    Brinton, Robert D.

    1983-01-01

    Although labor unions traditionally have fought for shorter working hours, there have been recent reversals in this trend. The Pulp and Paperboard Division of Temple-Eastex Incorporated converted to a 12-hour shift and found that safety improved, productivity increased, and overtime decreased. (JOW)

  15. Precipitation collector bias and its effects on temporal trends and spatial variability in National Atmospheric Deposition Program/National Trends Network data

    Science.gov (United States)

    Wetherbee, Gregory A.

    2017-01-01

    Precipitation samples have been collected by the National Atmospheric Deposition Program's (NADP) National Trends Network (NTN) using the Aerochem Metrics Model 301 (ACM) collector since 1978. Approximately one-third of the NTN ACM collectors have been replaced with N-CON Systems, Inc. Model ADS 00-120 (NCON) collectors. Concurrent data were collected over 6 years at 12 NTN sites using colocated ACM and NCON collectors in various precipitation regimes. Linear regression models of the colocated data were used to adjust for relative bias between the collectors. Replacement of ACM collectors with NCON collectors resulted in shifts in 10-year seasonal precipitation-weighted mean concentration (PWMC) trend slopes for: cations (−0.001 to −0.007 mgL−1yr−1), anions (−0.009 to −0.028 mgL−1yr−1), and hydrogen ion (+0.689 meqL-1yr−1). Larger shifts in NO3− and SO4−2 seasonal PWMC trend slopes were observed in the Midwest and Northeast US, where concentrations are generally higher than in other regions. Geospatial analysis of interpolated concentration rasters indicated regions of accentuated variability introduced by incorporation of NCON collectors into the NTN.

  16. Regime-switching stochastic volatility. Evidence from the crude oil market

    International Nuclear Information System (INIS)

    Vo, Minh T.

    2009-01-01

    This paper incorporates regime-switching into the stochastic volatility (SV) framework in an attempt to explain the behavior of crude oil prices in order to forecast their volatility. More specifically, it models the volatility of oil return as a stochastic volatility process whose mean is subject to shifts in regime. The shift is governed by a two-state first-order Markov process. The Bayesian Markov Chain Monte Carlo method is used to estimate the models. The main findings are: first, there is clear evidence of regime-switching in the oil market. Ignoring it will lead to a false impression that the volatility is highly persistent and therefore highly predictable. Second, incorporating regime-switching into the SV framework significantly enhances the forecasting power of the SV model. Third, the regime-switching stochastic volatility model does a good job in capturing major events affecting the oil market. (author)

  17. Regime-Based Versus Static Asset Allocation: Letting the Data Speak

    DEFF Research Database (Denmark)

    Nystrup, Peter; Hansen, Bo William; Madsen, Henrik

    2015-01-01

    Regime shifts present a big challenge to traditional strategic asset allocation. This article investigates whether regimebased asset allocation can effectively respond to changes in financial regimes at the portfolio level, in an effort to provide better long-term results than more static...... approaches can offer. The authors center their regime-based approach around a regime-switching model with time-varying parameters that can match financial markets’ tendency to change behavior abruptly and the fact that the new behavior often persists for several periods after a change. In an asset universe...

  18. Current US nuclear liability regime

    International Nuclear Information System (INIS)

    Brown, O.F.

    2000-01-01

    The Price-Anderson Act Adopted by US Congress in 1957 as the world's first national nuclear liability regime. It is a comprehensive, complicated and unique system and stems from special features of US legal regime and federal system of government. It differs from other systems by providing for 'economic', not legal; channeling of liability to facility operator and not recommended as model for other states, but most features adopted by other states and international conventions

  19. Totalitäre Regimes

    OpenAIRE

    Merkel, Wolfgang

    2004-01-01

    "The development of the term and the analytical concept of totalitarianism have gone through several stages since the 1920s. However, even in its most sophisticated form, the version seen in Friedrich/ Brzezinski, the concept exhibits substantial systematic classification problems and analytical weaknesses. This article attempts to frame the type of totalitarian regime within a general typology of political regimes. Special attention is dedicated to the problem of distinguishing autocra...

  20. Endogenous Monetary Policy Regime Change

    OpenAIRE

    Troy Davig; Eric M. Leeper

    2006-01-01

    This paper makes changes in monetary policy rules (or regimes) endogenous. Changes are triggered when certain endogenous variables cross specified thresholds. Rational expectations equilibria are examined in three models of threshold switching to illustrate that (i) expectations formation effects generated by the possibility of regime change can be quantitatively important; (ii) symmetric shocks can have asymmetric effects; (iii) endogenous switching is a natural way to formally model preempt...

  1. Global Trends in Workplace Learning

    Science.gov (United States)

    Lee, Lung-Sheng; Lai, Chun-Chin

    2012-01-01

    The paradigm of human resource development has shifted to workplace learning and performance. Workplace can be an organization, an office, a kitchen, a shop, a farm, a website, even a home. Workplace learning is a dynamic process to solve workplace problems through learning. An identification of global trends of workplace learning can help us to…

  2. Consistency of Trend Break Point Estimator with Underspecified Break Number

    Directory of Open Access Journals (Sweden)

    Jingjing Yang

    2017-01-01

    Full Text Available This paper discusses the consistency of trend break point estimators when the number of breaks is underspecified. The consistency of break point estimators in a simple location model with level shifts has been well documented by researchers under various settings, including extensions such as allowing a time trend in the model. Despite the consistency of break point estimators of level shifts, there are few papers on the consistency of trend shift break point estimators in the presence of an underspecified break number. The simulation study and asymptotic analysis in this paper show that the trend shift break point estimator does not converge to the true break points when the break number is underspecified. In the case of two trend shifts, the inconsistency problem worsens if the magnitudes of the breaks are similar and the breaks are either both positive or both negative. The limiting distribution for the trend break point estimator is developed and closely approximates the finite sample performance.

  3. Transition from weak wave turbulence regime to solitonic regime

    Science.gov (United States)

    Hassani, Roumaissa; Mordant, Nicolas

    2017-11-01

    The Weak Turbulence Theory (WTT) is a statistical theory describing the interaction of a large ensemble of random waves characterized by very different length scales. For both weak non-linearity and weak dispersion a different regime is predicted where solitons propagate while keeping their shape unchanged. The question under investigation here is which regime between weak turbulence or soliton gas does the system choose ? We report an experimental investigation of wave turbulence at the surface of finite depth water in the gravity-capillary range. We tune the wave dispersion and the level of nonlinearity by modifying the depth of water and the forcing respectively. We use space-time resolved profilometry to reconstruct the deformed surface of water. When decreasing the water depth, we observe a drastic transition between weak turbulence at the weakest forcing and a solitonic regime at stronger forcing. We characterize the transition between both states by studying their Fourier Spectra. We also study the efficiency of energy transfer in the weak turbulence regime. We report a loss of efficiency of angular transfer as the dispersion of the wave is reduced until the system bifurcates into the solitonic regime. This project has recieved funding from the European Research Council (ERC, Grant Agreement No. 647018-WATU).

  4. Choice Shifts in Groups

    OpenAIRE

    Kfir Eliaz; Debraj Ray

    2004-01-01

    The phenomenon of "choice shifts" in group decision-making is fairly ubiquitous in the social psychology literature. Faced with a choice between a ``safe" and ``risky" decision, group members appear to move to one extreme or the other, relative to the choices each member might have made on her own. Both risky and cautious shifts have been identified in different situations. This paper demonstrates that from an individual decision-making perspective, choice shifts may be viewed as a systematic...

  5. Implementing OpenShift

    CERN Document Server

    Miller, Adam

    2013-01-01

    A standard tutorial-based approach to using OpenShift and deploying custom or pre-built web applications to the OpenShift Online cloud.This book is for software developers and DevOps alike who are interested in learning how to use the OpenShift Platform-as-a-Service for developing and deploying applications, how the environment works on the back end, and how to deploy their very own open source Platform-as-a-Service based on the upstream OpenShift Origin project.

  6. Insomnia in shift work.

    Science.gov (United States)

    Vallières, Annie; Azaiez, Aïda; Moreau, Vincent; LeBlanc, Mélanie; Morin, Charles M

    2014-12-01

    Shift work disorder involves insomnia and/or excessive sleepiness associated with the work schedule. The present study examined the impact of insomnia on the perceived physical and psychological health of adults working on night and rotating shift schedules compared to day workers. A total of 418 adults (51% women, mean age 41.4 years), including 51 night workers, 158 rotating shift workers, and 209 day workers were selected from an epidemiological study. An algorithm was used to classify each participant of the two groups (working night or rotating shifts) according to the presence or absence of insomnia symptoms. Each of these individuals was paired with a day worker according to gender, age, and income. Participants completed several questionnaires measuring sleep, health, and psychological variables. Night and rotating shift workers with insomnia presented a sleep profile similar to that of day workers with insomnia. Sleep time was more strongly related to insomnia than to shift work per se. Participants with insomnia in the three groups complained of anxiety, depression, and fatigue, and reported consuming equal amounts of sleep-aid medication. Insomnia also contributed to chronic pain and otorhinolaryngology problems, especially among rotating shift workers. Work productivity and absenteeism were more strongly related to insomnia. The present study highlights insomnia as an important component of the sleep difficulties experienced by shift workers. Insomnia may exacerbate certain physical and mental health problems of shift workers, and impair their quality of life. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. The Treaty of Lisbon and the European Border Control Regime

    Directory of Open Access Journals (Sweden)

    Marianne Takle

    2012-08-01

    Full Text Available The question raised in the article is how the new provisions of the Lisbon Treaty and the Stockholm programme concerning the EU’s asylum and migration policy might consolidate existing trends within the European border control regime. The regime is defined by a combination of three features: (i a harmonisation of categories among the EU/Schengen member states, (ii a growing use of new technology in networked databases and (iii an increasing sorting of individuals based on security concerns. Although none of these features is new, the combination gives a new impetus to the European border control regime. The article concludes that the Lisbon Treaty and the Stockholm programme consolidate and strengthen existing trends. This implies that policies on border control, asylum, immigration, judicial cooperation and police cooperation are consolidated in a broader approach to border control, and that there is a strengthening of EU foreign policy within the European border control regime. The boundaries between previously dispersed policy areas are blurred. The combination of different aspects of security and various levels of authority requires coordination of policies with substantially different goals, and goes beyond mere border control.

  8. The political use of psychiatry: A comparison between totalitarian regimes.

    Science.gov (United States)

    Buoli, Massimiliano; Giannuli, Aldo Sabino

    2017-03-01

    After the end of Second World War, the recent experience of the Nazi horrors stimulated a debate about the political use of psychiatry. Over the years, the focus shifted on major dictatorships of the time and especially on Soviet Union. This article aims to provide a critical review of the ways in which psychiatry was used by totalitarian regimes of the 20th century. We summarized relevant literature about political use of psychiatry in totalitarian regimes of the 20th century, with particular focus on Fascism, Nazism, Argentina dictatorship, Soviet Union and China. One of the features that are common to most of the dictatorships is that the use of psychiatry has become more prominent when the regimes have had the need to make more acceptable the imprisonment of enemies in the eyes of the world. This for example happened in the Nazi regime when sterilization and killing of psychiatric patients was explained as a kind of euthanasia, or in the Soviet Union after the formal closure of the corrective labor camps and the slow resumption of relations with the capitalistic world, or in China to justify persecution of religious minorities and preserve economic relations with Western countries. Psychiatry has been variously used by totalitarian regimes as a means of political persecution and especially when it was necessary to make acceptable to public opinion the imprisonment of political opponents.

  9. Evaluation and Comparison of Extremal Hypothesis-Based Regime Methods

    Directory of Open Access Journals (Sweden)

    Ishwar Joshi

    2018-03-01

    Full Text Available Regime channels are important for stable canal design and to determine river response to environmental changes, e.g., due to the construction of a dam, land use change, and climate shifts. A plethora of methods is available describing the hydraulic geometry of alluvial rivers in the regime. However, comparison of these methods using the same set of data seems lacking. In this study, we evaluate and compare four different extremal hypothesis-based regime methods, namely minimization of Froude number (MFN, maximum entropy and minimum energy dissipation rate (ME and MEDR, maximum flow efficiency (MFE, and Millar’s method, by dividing regime channel data into sand and gravel beds. The results show that for sand bed channels MFN gives a very high accuracy of prediction for regime channel width and depth. For gravel bed channels we find that MFN and ‘ME and MEDR’ give a very high accuracy of prediction for width and depth. Therefore the notion that extremal hypotheses which do not contain bank stability criteria are inappropriate for use is shown false as both MFN and ‘ME and MEDR’ lack bank stability criteria. Also, we find that bank vegetation has significant influence in the prediction of hydraulic geometry by MFN and ‘ME and MEDR’.

  10. On the regimes of premixing

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, S.; Theofanous, T.G.; Yuen, W.W. [California Univ., Santa Barbara, CA (United States). Center for Risk Studies and Safety

    1998-01-01

    The conditions of the MAGICO-2000 experiment are extended to more broadly investigate the regimes of premixing, and the corresponding internal structures of mixing zones. With the help of the data and numerical simulations using the computer code PM-ALPHA, we can distinguish extremes of behavior dominated by inertia and thermal effects - we name these the inertia and thermal regimes, respectively. This is an important distinction that should guide future experiments aimed at code verification in this area. Interesting intermediate behaviors are also delineated and discussed. (author)

  11. Blue and red shifted temperature dependence of implicit phonon shifts in graphene

    Science.gov (United States)

    Mann, Sarita; Jindal, V. K.

    2017-07-01

    We have calculated the implicit shift for various modes of frequency in a pure graphene sheet. Thermal expansion and Grüneisen parameter which are required for implicit shift calculation have already been studied and reported. For this calculation, phonon frequencies are obtained using force constants derived from dynamical matrix calculated using VASP code where the density functional perturbation theory (DFPT) is used in interface with phonopy software. The implicit phonon shift shows an unusual behavior as compared to the bulk materials. The frequency shift is large negative (red shift) for ZA and ZO modes and the value of negative shift increases with increase in temperature. On the other hand, blue shift arises for all other longitudinal and transverse modes with a similar trend of increase with increase in temperature. The q dependence of phonon shifts has also been studied. Such simultaneous red and blue shifts in transverse or out plane modes and surface modes, respectively leads to speculation of surface softening in out of plane direction in preference to surface melting.

  12. Weather regimes in past climate atmospheric general circulation model simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kageyama, M.; Ramstein, G. [CEA Saclay, Gif-sur-Yvette (France). Lab. des Sci. du Climat et de l' Environnement; D' Andrea, F.; Vautard, R. [Laboratoire de Meteorologie Dynamique, Ecole Normale Superieure, Paris (France); Valdes, P.J. [Department of Meteorology, University of Reading (United Kingdom)

    1999-10-01

    We investigate the climates of the present-day, inception of the last glaciation (115000 y ago) and last glacial maximum (21000 y ago) in the extratropical north Atlantic and Europe, as simulated by the laboratoire de Meteorologie dynamique atmospheric general circulation model. We use these simulations to investigate the low-frequency variability of the model in different climates. The aim is to evaluate whether changes in the intraseasonal variability, which we characterize using weather regimes, can help describe the impact of different boundary conditions on climate and give a better understanding of climate change processes. Weather regimes are defined as the most recurrent patterns in the 500 hPa geopotential height, using a clustering algorithm method. The regimes found in the climate simulations of the present-day and inception of the last glaciation are similar in their number and their structure. It is the regimes' populations which are found to be different for these climates, with an increase of the model's blocked regime and a decrease in the zonal regime at the inception of the last glaciation. This description reinforces the conclusions from a study of the differences between the climatological averages of the different runs and confirms the northeastward shift to the tail of the Atlantic storm-track, which would favour more precipitation over the site of growth of the Fennoscandian ice-sheet. On the other hand, the last glacial maximum results over this sector are not found to be classifiable, showing that the change in boundary conditions can be responsible for severe changes in the weather regime and low-frequency dynamics. The LGM Atlantic low-frequency variability appears to be dominated by a large-scale retrogressing wave with a period 40 to 50 days. (orig.)

  13. Shifted Independent Component Analysis

    DEFF Research Database (Denmark)

    Mørup, Morten; Madsen, Kristoffer Hougaard; Hansen, Lars Kai

    2007-01-01

    Delayed mixing is a problem of theoretical interest and practical importance, e.g., in speech processing, bio-medical signal analysis and financial data modelling. Most previous analyses have been based on models with integer shifts, i.e., shifts by a number of samples, and have often been carried...

  14. Homogeneous bilateral block shifts

    Indian Academy of Sciences (India)

    Douglas class were classified in [3]; they are unilateral block shifts of arbitrary block size (i.e. dim H(n) can be anything). However, no examples of irreducible homogeneous bilateral block shifts of block size larger than 1 were known until now.

  15. OpenShift cookbook

    CERN Document Server

    Gulati, Shekhar

    2014-01-01

    If you are a web application developer who wants to use the OpenShift platform to host your next big idea but are looking for guidance on how to achieve this, then this book is the first step you need to take. This is a very accessible cookbook where no previous knowledge of OpenShift is needed.

  16. Skiing trends

    Science.gov (United States)

    Charles R. Goeldner; Stacy Standley

    1980-01-01

    A brief historical overview of skiing is presented, followed by a review of factors such as energy, population trends, income, sex, occupation and attitudes which affect the future of skiing. A. C. Neilson's Sports Participation Surveys show that skiing is the second fastest growing sport in the country. Skiing Magazine's study indicates there are...

  17. Billing Trends

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Billing Trends. Internet access: Bandwidth becoming analogous to electric power. Only maximum capacity (load) is fixed; Charges based on usage (units). Leased line bandwidth: Billing analogous to phone calls. But bandwidth is variable.

  18. Food Trends.

    Science.gov (United States)

    Schwenk, Nancy E.

    1991-01-01

    An overall perspective on trends in food consumption is presented. Nutrition awareness is at an all-time high; consumption is influenced by changes in disposable income, availability of convenience foods, smaller household size, and an increasing proportion of ethnic minorities in the population. (18 references) (LB)

  19. Josephson shift registers

    International Nuclear Information System (INIS)

    Przybysz, J.X.

    1989-01-01

    This paper gives a review of Josephson shift register circuits that were designed, fabricated, or tested, with emphasis on work in the 1980s. Operating speed is most important, since it often limits system performance. Older designs used square-wave clocks, but most modern designs use offset sine waves, with either two or three phases. Operating margins and gate bias uniformity are key concerns. The fastest measured Josephson shift register operated at 2.3 GHz, which compares well with a GaAs shift register that consumes 250 times more power. The difficulties of high-speed testing have prevented many Josephson shift registers from being operated at their highest speeds. Computer simulations suggest that 30-GHz operation is possible with current Nb/Al 2 O 3 /Nb technology. Junctions with critical current densities near 10 kA/cm 2 would make 100-GHz shift registers feasible

  20. Evaluation of Five Different Regimes For the Treatment of Vitiligo

    Directory of Open Access Journals (Sweden)

    J S Pasricha

    1989-01-01

    Full Text Available Response of vitiligo patients to five different regimes was evaluated taking only those patients who had either static or progressively increasing lesions. Selection of the regimen depended upon the clinical characteristics of the disease. Each regime was tried for at least 4 months and if a patient didnot improve with one regime, he was shifted to another regime. A patient was considered to have improved, if the lesions started regimenting or the previously progressive lesions stopped increasing further. Regime I consisted of 150 mg levamisol orally on two consecutive days per week, given to 13 cases, it resulted in improvement in 7 (53.80/o. Regime II consisted of levamisole in the same dose combined with once a day topical massage with 0.1% fluocinolone acetonide acetate cream; it led to improvement in 27 (81.8% of the 33 cases. Regime III consisted of 3 mg betamethasone orally on alternate days combined with levamisole and topical fluocinolone; given to 32 cases, it was successful in 28 (87.50/o. A combination of 2 mg betamethasone orally alternating with 20 mg 8-methoxypsoralen and sun exposure (regime IV caused improvement in 17 (85% of the 20 cases. An oral mini pulse consisting of 5 mg betamethasone orally twice a week combined with 50 mg cyclophosphimide daily orally (regime V was successful in 20 (90.9% of the 22 cases, the remaining two cases showed unprovement when the dose ofbetamethasonc .was increased from 5 mg to 7.5 mg twice a week. Thus ultimately each one of the 91 patients responded to one or the other regime. The side effects were minimal and insignificant.The degree of improvement at the time of analysis was 100% in 23.3% cases, 50-100% in 44.2′Yo cases and less than 50% in 32.5%, after 4-14 months of treatment. It is felt that the results may be better after a longer follow-up although all patients are not expected to get complete repigmentation.

  1. Land degradation and property regimes

    Science.gov (United States)

    Paul M. Beaumont; Robert T. Walker

    1996-01-01

    This paper addresses the relationship between property regimes and land degradation outcomes, in the context of peasant agriculture. We consider explicitly whether private property provides for superior soil resource conservation, as compared to common property and open access. To assess this we implement optimization algorithms on a supercomputer to address resource...

  2. Regime identification in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Giannone, L; Sips, A C C; Kardaun, O; Spreitler, F; Suttrop, W

    2004-01-01

    The ability to recognize the transition from the L-mode to the H-mode or from the H-mode to the improved H-mode reliably from a conveniently small number of measurements in real time is of increasing importance for machine control. Discriminant analysis has been applied to regime identification of plasma discharges in the ASDEX Upgrade tokamak. An observation consists of a set of plasma parameters averaged over a time slice in a discharge. The data set consists of all observations over different discharges and time slices. Discriminant analysis yields coefficients allowing the classification of a new observation. The results of a frequentist and a formal Bayesian approach to discriminant analysis are compared. With five plasma variables, a failure rate of 1.3% for predicting the L-mode and the H-mode confinement regime was achieved. With five plasma variables, a failure rate of 5.3% for predicting the H-mode and the improved H-mode confinement regime was achieved. The coefficients derived by discriminant analysis have been applied subsequently to discharges to illustrate the operation of regime identification in a real time control system

  3. Monetary regimes in open economies

    NARCIS (Netherlands)

    Korpos, A.

    2006-01-01

    This thesis presents a two-country open economy framework for the analysis of strategic interactions among monetary authorities and wage bargaining institutions. From this perspective, the thesis investigates the economic consequences of replacing flexible and fixed exchange rate regimes with a

  4. Ozone time scale decomposition and trend assessment from surface observations in National Parks of the United States

    Science.gov (United States)

    Mao, H.; McGlynn, D. F.; Wu, Z.; Sive, B. C.

    2017-12-01

    A time scale decomposition technique, the Ensemble Empirical Mode Decomposition (EEMD), has been employed to decompose the time scales in long-term ozone measurement data at 24 US National Park Service sites. Time scales of interest include the annual cycle, variability by large scale climate oscillations, and the long-term trend. The implementation of policy regulations was found to have had a greater effect on sites nearest to urban regions. Ozone daily mean values increased until around the late 1990s followed by decreasing trends during the ensuing decades for sites in the East, southern California, and northwestern Washington. Sites in the Midwest did not experience a reversal of trends from positive to negative until the mid- to late 2000s. The magnitude of the annual amplitude decreased for nine sites and increased for three sites. Stronger decreases in the annual amplitude occurred in the East, with more sites in the East experiencing decreases in annual amplitude than in the West. The date of annual ozone peaks and minimums has changed for 12 sites in total, but those with a shift in peak date did not necessarily have a shift in the trough date. There appeared to be a link between peak dates occurring earlier and a decrease in the annual amplitude. This is likely related to a decrease in ozone titration due to NOx emission reductions. Furthermore, it was found that the shift in the Pacific Decadal Oscillation (PDO) regime from positive to negative in 1998-1999 resulting in an increase in occurrences of La Niña-like conditions had the effect of directing more polluted air masses from East Asia to higher latitudes over North America. This change in PDO regime was likely one main factor causing the increase in ozone concentrations on all time scales at an Alaskan site DENA-HQ.

  5. Trends in food packaging: Arising opportunities and shifting demands

    NARCIS (Netherlands)

    Gerding, T.K.; Rijk, M.A.H.; Jetten, J.; Berg, F. van den; Kruijf, N. de

    1996-01-01

    Packaging foodstuffs is a dynamic process which continually has to respond to the changes in supply and demand which are the result of adaptations to the varying demands of the consumer, changes in retail practices, technological innovations, new materials and developments in legislation, especially

  6. Food crises, food regimes and food movements: rumblings of reform or tides of transformation?

    Science.gov (United States)

    Holt Giménez, Eric; Shattuck, Annie

    2011-01-01

    This article addresses the potential for food movements to bring about substantive changes to the current global food system. After describing the current corporate food regime, we apply Karl Polanyi's 'double-movement' thesis on capitalism to explain the regime's trends of neoliberalism and reform. Using the global food crisis as a point of departure, we introduce a comparative analytical framework for different political and social trends within the corporate food regime and global food movements, characterizing them as 'Neoliberal', 'Reformist', 'Progressive', and 'Radical', respectively, and describe each trend based on its discourse, model, and key actors, approach to the food crisis, and key documents. After a discussion of class, political permeability, and tensions within the food movements, we suggest that the current food crisis offers opportunities for strategic alliances between Progressive and Radical trends within the food movement. We conclude that while the food crisis has brought a retrenchment of neoliberalization and weak calls for reform, the worldwide growth of food movements directly and indirectly challenge the legitimacy and hegemony of the corporate food regime. Regime change will require sustained pressure from a strong global food movement, built on durable alliances between Progressive and Radical trends.

  7. Industry trends

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This section discusses the US energy supply and demand situation including projections for energy use, the clean coal industry (constraints of regulation on investment in new technologies, technology trends, and current pollution control efficiency), opportunities in clean coal technology (Phase 2 requirements of Title 4 of the Clean Air Act, scrubber demand for lime and limestone, and demand for low sulfur coal), and the international market of clean coal technologies

  8. Nurses' shift reports

    DEFF Research Database (Denmark)

    Buus, Niels; Hoeck, Bente; Hamilton, Bridget Elizabeth

    2017-01-01

    AIMS AND OBJECTIVES: To identify reporting practices that feature in studies of nurses' shift reports across diverse nursing specialities. The objectives were to perform an exhaustive systematic literature search and to critically review the quality and findings of qualitative field studies...... of nurses' shift reports. BACKGROUND: Nurses' shift reports are routine occurrences in healthcare organisations that are viewed as crucial for patient outcomes, patient safety and continuity of care. Studies of communication between nurses attend primarily to 1:1 communication and analyse the adequacy...... and accuracy of patient information and feature handovers at the bedside. Still, verbal reports between groups of nurses about patients are commonplace. Shift reports are obvious sites for studying the situated accomplishment of professional nursing at the group level. This review is focused exclusively...

  9. Shift Verification and Validation

    Energy Technology Data Exchange (ETDEWEB)

    Pandya, Tara M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Evans, Thomas M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Davidson, Gregory G [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnson, Seth R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Godfrey, Andrew T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-07

    This documentation outlines the verification and validation of Shift for the Consortium for Advanced Simulation of Light Water Reactors (CASL). Five main types of problems were used for validation: small criticality benchmark problems; full-core reactor benchmarks for light water reactors; fixed-source coupled neutron-photon dosimetry benchmarks; depletion/burnup benchmarks; and full-core reactor performance benchmarks. We compared Shift results to measured data and other simulated Monte Carlo radiation transport code results, and found very good agreement in a variety of comparison measures. These include prediction of critical eigenvalue, radial and axial pin power distributions, rod worth, leakage spectra, and nuclide inventories over a burn cycle. Based on this validation of Shift, we are confident in Shift to provide reference results for CASL benchmarking.

  10. Molecular Electronic Shift Registers

    Science.gov (United States)

    Beratan, David N.; Onuchic, Jose N.

    1990-01-01

    Molecular-scale shift registers eventually constructed as parts of high-density integrated memory circuits. In principle, variety of organic molecules makes possible large number of different configurations and modes of operation for such shift-register devices. Several classes of devices and implementations in some specific types of molecules proposed. All based on transfer of electrons or holes along chains of repeating molecular units.

  11. Exchange rate regimes and monetary arrangements

    Directory of Open Access Journals (Sweden)

    Ivan Ribnikar

    2005-06-01

    Full Text Available There is a close relationship between a country’s exchange rate regime and monetary arrangement and if we are to examine monetary arrangements then exchange rate regimes must first be analysed. Within the conventional and most widely used classification of exchange rate regimes into rigid and flexible or into polar regimes (hard peg and float on one side, and intermediate regimes on the other there, is a much greater variety among intermediate regimes. A more precise and, as will be seen, more useful classification of exchange rate regimes is the first topic of the paper. The second topic is how exchange rate regimes influence or determine monetary arrangements and monetary policy or monetary policy regimes: monetary autonomy versus monetary nonautonomy and discretion in monetary policy versus commitment in monetary policy. Both topics are important for countries on their path to the EU and the euro area

  12. Status and trends of U.S. pulpwood market.

    Science.gov (United States)

    Peter J. Ince

    2009-01-01

    Global trends in pulp, paper, and paperboard have deeply affected U.S. pulpwood markets since the late 1990s. Global trends included a shift of growth in paper and paperboard production from North America to Europe and Asia over the past decade. This trend was associated with generally slower growth in U.S. industrial production and displacement of growth in print...

  13. Detecting spatial regimes in ecosystems

    Science.gov (United States)

    Sundstrom, Shana M.; Eason, Tarsha; Nelson, R. John; Angeler, David G.; Barichievy, Chris; Garmestani, Ahjond S.; Graham, Nicholas A.J.; Granholm, Dean; Gunderson, Lance; Knutson, Melinda; Nash, Kirsty L.; Spanbauer, Trisha; Stow, Craig A.; Allen, Craig R.

    2017-01-01

    Research on early warning indicators has generally focused on assessing temporal transitions with limited application of these methods to detecting spatial regimes. Traditional spatial boundary detection procedures that result in ecoregion maps are typically based on ecological potential (i.e. potential vegetation), and often fail to account for ongoing changes due to stressors such as land use change and climate change and their effects on plant and animal communities. We use Fisher information, an information theory-based method, on both terrestrial and aquatic animal data (U.S. Breeding Bird Survey and marine zooplankton) to identify ecological boundaries, and compare our results to traditional early warning indicators, conventional ecoregion maps and multivariate analyses such as nMDS and cluster analysis. We successfully detected spatial regimes and transitions in both terrestrial and aquatic systems using Fisher information. Furthermore, Fisher information provided explicit spatial information about community change that is absent from other multivariate approaches. Our results suggest that defining spatial regimes based on animal communities may better reflect ecological reality than do traditional ecoregion maps, especially in our current era of rapid and unpredictable ecological change.

  14. Cloud regimes as phase transitions

    Science.gov (United States)

    Stechmann, Samuel; Hottovy, Scott

    2017-11-01

    Clouds are repeatedly identified as a leading source of uncertainty in future climate predictions. Of particular importance are stratocumulus clouds, which can appear as either (i) closed cells that reflect solar radiation back to space or (ii) open cells that allow solar radiation to reach the Earth's surface. Here we show that these clouds regimes - open versus closed cells - fit the paradigm of a phase transition. In addition, this paradigm characterizes pockets of open cells (POCs) as the interface between the open- and closed-cell regimes, and it identifies shallow cumulus clouds as a regime of higher variability. This behavior can be understood using an idealized model for the dynamics of atmospheric water as a stochastic diffusion process. Similar viewpoints of deep convection and self-organized criticality will also be discussed. With these new conceptual viewpoints, ideas from statistical mechanics could potentially be used for understanding uncertainties related to clouds in the climate system and climate predictions. The research of S.N.S. is partially supported by a Sloan Research Fellowship, ONR Young Investigator Award N00014-12-1-0744, and ONR MURI Grant N00014-12-1-0912.

  15. Late Holocene influence of societies on the fire regime in southern Québec temperate forests

    Science.gov (United States)

    Blarquez, Olivier; Talbot, Julie; Paillard, Jordan; Lapointe-Elmrabti, Lyna; Pelletier, Nicolas; Gates St-Pierre, Christian

    2018-01-01

    Climatic change that occurred during the Holocene is often recognized as the main factor for explaining fire dynamics, while the influence of human societies is less apparent. In eastern North America, human influence on fire regime before European settlement has been debated, mainly because of a paucity of sites and paleoecological techniques that can distinguish human influences unequivocally from climate. We applied a multiproxy analysis to a 12 000-year-old paleoecological sequence from a site in the vicinity of known settlement areas that were occupied over more than 7000 years. From this analysis, we were able detect the human influence on the fire regime before and after European colonization. Fire occurrence and fire return intervals (FRI) were based on analysis of sedimentary charcoals at a high temporal and spatial resolution. Fire occurrence was then compared to vegetation that was reconstructed from pollen analysis, from population densities deduced from archeological site dating, from demographic and technological models, and from climate reconstructed using general circulation models and ice-core isotopes. Holocene mean FRI was short (164 ± 134 years) and associated with small charcoal peaks that were likely indicative of surface fires affecting small areas. After 1500 BP, large vegetation changes and human demographic growth that was demonstrated through increased settlement evidence likely caused the observed FRI lengthening (301 ± 201 years), which occurred without significant changes in climate. Permanent settlement by Europeans in the area around 1800 AD was followed by a substantial demographic increase, leading to the establishment of Gatineau, Hull and Ottawa. This trend was accompanied by a shift in the charcoal record toward anthropogenic particles that were reflective of fossil fuel burning and an apparent absence of wood charcoal that would be indicative of complete fire suppression. An anthropogenic fire regime that was characterized by

  16. The NPT regime, present and future global security: an American view

    International Nuclear Information System (INIS)

    Thompson, Sam.

    1987-01-01

    Although not perfect, an international non-proliferation regime as set out by the IAEA and Non-Proliferation Treaty is in existence. The history of the involvement of the United States in the development of this regime is mentioned as a background to explaining the current approach of the Reagan Administration to non-proliferation. Trends and challenges which may affect future global security are then identified and discussed. The author is optimistic about the future. (U.K.)

  17. Pluton emplacement in a releasing bend in a transpressive regime: the arrozal granite in the Paraíba do Sul shear belt, Rio de Janeiro.

    Science.gov (United States)

    Nummer, Alexis R; Machado, Rômulo; Dehler, Nolan M

    2007-06-01

    The Arrozal Granite, situated in the southwestern region of the State of Rio de Janeiro, has a granitic to granodioritic composition. It contains a strong mylonitic foliation along its border, passing gradually to a well-developed magmatic foliation towards its center. Structural analysis indicates that the Arrozal Granite was emplaced along the Além-Paraíba Shear Zone in a dextral transpressive tectonic regime. A regional shift of the trend along this shear zone from NE-SW to E-W, observed in the area, is interpreted to be casually related to the creation of space for the emplacement of the granite. Our data indicate that releasing bends may have played an important role for space generation during the emplacement of the Arrozal Granite and other plutons.

  18. Macroeconomic regime and labor market: the Argentine experience of the past two decades

    Directory of Open Access Journals (Sweden)

    Luis Beccaria

    2016-12-01

    Full Text Available This document analyzes the interactions between macroeconomic regimes, employment generation and the dynamics of labor incomes in Argentina under two different macroeconomic regimes: the currency board regime of the 1990s and the high real exchange rate regime that followed. The former, characterized by a strong currency overvaluation, had a negative impact on economic activity and the labor market. However, the maintenance of a competitive real exchange rate does not by itself guarantee the sustained positive performance of the labor market, as it became evident in Argentina during the 2000s. Although the sizable depreciation of the peso –together with a positive international context- favored the expansion of output and employment, the initial concern of maintaining the real exchange rate at a competitive level was not continued with policies aimed to counteract the appreciation trend that appeared a few years after the implementation of the new regime.

  19. Oil and gas fiscal regimes of the western Canadian provinces

    International Nuclear Information System (INIS)

    1991-11-01

    This report compares the fiscal regimes in British Columbia, Alberta, Saskatchewan and Manitoba. During 1985-1988, federal and provincial governments have made numerous fiscal changes, many in response to the drop in world oil prices. The new fiscal policies generally have reflected governments' willingness to forego revenues in an effort to aid the oil and gas industry, with certain exemptions. Since 1988, changes have reflected trends of consolidation and less government willingness to forego revenues. A federal large corporations capital tax has been introduced, the natural gas exploration holiday in Alberta expired, new oil royalties were introduced, and changes were made in fiscal regimes to accomodate horizontal drilling in Saskatchewan and Manitoba. In this document, the existing corporate tax regime is described. A comparison of fiscal regimes must recognize the differing scale and nature of oil and gas operations among the 4 provinces, with Alberta accounting for 80-90% of Canada's oil and gas productions, while British Columbia, Saskatchewan and Manitoba are much smaller producers. The document describes Crown royalties and incentives and freehold taxes for each type of fuel (crude oil, natural gas, natural gas byproducts, nonconventional oil). 8 figs

  20. Alberta oil sands royalty regime

    International Nuclear Information System (INIS)

    Asgarpour, S.

    2004-01-01

    The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

  1. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Sherwood, D.G.; Wilson, J.F.; Salton, R.B.; Fensterer, H.F.

    1981-01-01

    A mechanical spectral shift reactor comprises apparatus for inserting and withdrawing water displacer elements from the reactor core for selectively changing the water-moderator volume in the core thereby changing the reactivity of the core. The apparatus includes drivemechanisms for moving the displacer elements relative to the core and guide mechanisms for guiding the displayer rods through the reactor vessel

  2. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Sherwood, D.G.; Wilson, J.F.; Salton, R.B.; Fensterer, H.F.

    1982-01-01

    A mechanical spectral shift reactor comprises apparatus for inserting and withdrawing water displacer elements from the reactor core for selectively changing the water-moderator volume in the core thereby changing the reactivity of the core. The apparatus includes drive mechanisms for moving the displacer elements relative to the core and guide mechanisms for guiding the displacer rods through the reactor vessel. (author)

  3. Adaptation in Collaborative Governance Regimes

    Science.gov (United States)

    Emerson, Kirk; Gerlak, Andrea K.

    2014-10-01

    Adaptation and the adaptive capacity of human and environmental systems have been of central concern to natural and social science scholars, many of whom characterize and promote the need for collaborative cross-boundary systems that are seen as flexible and adaptive by definition. Researchers who study collaborative governance systems in the public administration, planning and policy literature have paid less attention to adaptive capacity specifically and institutional adaptation in general. This paper bridges the two literatures and finds four common dimensions of capacity, including structural arrangements, leadership, knowledge and learning, and resources. In this paper, we focus on institutional adaptation in the context of collaborative governance regimes and try to clarify and distinguish collaborative capacity from adaptive capacity and their contributions to adaptive action. We posit further that collaborative capacities generate associated adaptive capacities thereby enabling institutional adaptation within collaborative governance regimes. We develop these distinctions and linkages between collaborative and adaptive capacities with the help of an illustrative case study in watershed management within the National Estuary Program.

  4. Measuring the effectiveness of international environmental regimes

    Energy Technology Data Exchange (ETDEWEB)

    Helm, C.; Sprinz, D.F.

    1999-05-01

    While past research has emphasized the importance of international regimes for international governance, systematic assessments of regime effects are missing. This article derives a standardized measurement concept for the effectiveness of international environmental regimes by developing an operational rational choice calculus to evaluate actual policy simultaneously against a non-regime counterfactual and a collective optimum. Subsequently, the empirical feasibility of the measurement instrument is demonstrated by way of two international treaties regulating transboundary air pollution in Europe. The results demonstrate that the regimes indeed show positive effects - but fall substantially short of the collective optima. (orig.)

  5. Sensitivity to spatial and temporal scale and fire regime inputs in deriving fire regime condition class

    Science.gov (United States)

    Linda Tedrow; Wendel J. Hann

    2015-01-01

    The Fire Regime Condition Class (FRCC) is a composite departure measure that compares current vegetation structure and fire regime to historical reference conditions. FRCC is computed as the average of: 1) Vegetation departure (VDEP) and 2) Regime (frequency and severity) departure (RDEP). In addition to the FRCC rating, the Vegetation Condition Class (VCC) and Regime...

  6. Tempo of Diversification of Global Amphibians: One-Constant Rate, One-Continuous Shift or Multiple-Discrete Shifts?

    Directory of Open Access Journals (Sweden)

    Youhua Chen

    2014-01-01

    Full Text Available In this brief report, alternative time-varying diversification rate models were fitted onto the phylogeny of global amphibians by considering one-constant-rate (OCR, one-continuous-shift (OCS and multiplediscrete- shifts (MDS situations. The OCS diversification model was rejected by γ statistic (γ=-5.556, p⁄ 0.001, implying the existence of shifting diversification rates for global amphibian phylogeny. Through model selection, MDS diversification model outperformed OCS and OCR models using “laser” package under R environment. Moreover, MDS models, implemented using another R package “MEDUSA”, indicated that there were sixteen shifts over the internal nodes for amphibian phylogeny. Conclusively, both OCS and MDS models are recommended to compare so as to better quantify rate-shifting trends of species diversification. MDS diversification models should be preferential for large phylogenies using “MEDUSA” package in which any arbitrary numbers of shifts are allowed to model.

  7. Fire regime in Mediterranean ecosystem

    Science.gov (United States)

    Biondi, Guido; Casula, Paolo; D'Andrea, Mirko; Fiorucci, Paolo

    2010-05-01

    The analysis of burnt areas time series in Mediterranean regions suggests that ecosystems characterising this area consist primarily of species highly vulnerable to the fire but highly resilient, as characterized by a significant regenerative capacity after the fire spreading. In a few years the area burnt may once again be covered by the same vegetation present before the fire. Similarly, Mediterranean conifer forests, which often refers to plantations made in order to reforest the areas most severely degraded with high erosion risk, regenerate from seed after the fire resulting in high resilience to the fire as well. Only rarely, and usually with negligible damages, fire affects the areas covered by climax species in relation with altitude and soil types (i.e, quercus, fagus, abies). On the basis of these results, this paper shows how the simple Drossel-Schwabl forest fire model is able to reproduce the forest fire regime in terms of number of fires and burned area, describing whit good accuracy the actual fire perimeters. The original Drossel-Schwabl model has been slightly modified in this work by introducing two parameters (probability of propagation and regrowth) specific for each different class of vegetation cover. Using model selection methods based on AIC, the model with the optimal number of classes with different fire behaviour was selected. Two different case studies are presented in this work: Regione Liguria and Regione Sardegna (Italy). Both regions are situated in the center of the Mediterranean and are characterized by a high number of fires and burned area. However, the two regions have very different fire regimes. Sardinia is affected by the fire phenomenon only in summer whilst Liguria is affected by fires also in winter, with higher number of fires and larger burned area. In addition, the two region are very different in vegetation cover. The presence of Mediterranean conifers, (Pinus Pinaster, Pinus Nigra, Pinus halepensis) is quite spread in

  8. Towards a green urban economy? Unravelling urban sustainability transitions from a regime perspective

    NARCIS (Netherlands)

    Mans, U.; Meerow, S.

    2012-01-01

    The current debate about sustainability transitions has embraced the multi-level perspective as a useful methodological tool for assessing the dynamics that are at play between landscape, regime and niche. As a consequence, the thinking about socio-technical transitions has gradually shifted in

  9. Spatiotemporal changes in precipitation extremes over Yangtze River basin, China, considering the rainfall shift in the late 1970s

    Science.gov (United States)

    Gao, Tao; Xie, Lian

    2016-12-01

    Precipitation extremes are the dominated causes for the formation of severe flood disasters at regional and local scales under the background of global climate change. In the present study, five annual extreme precipitation events, including 1, 7 and 30 day annual maximum rainfall and 95th and 97.5th percentile threshold levels, are analyzed relating to the reference period 1960-2011 from 140 meteorological stations over Yangtze River basin (YRB). A generalized extreme value (GEV) distribution is applied to fit annual and percentile extreme precipitation events at each station with return periods up to 200 years. The entire time period is divided into preclimatic (preceding climatic) period 1960-1980 and aftclimatic (after climatic) period 1981-2011 by considering distinctly abrupt shift of precipitation regime in the late 1970s across YRB. And the Mann-Kendall trend test is adopted to conduct trend analysis during pre- and aftclimatic periods, respectively, for the purpose of exploring possible increasing/decreasing patterns in precipitation extremes. The results indicate that the increasing trends for return values during aftclimatic period change significantly in time and space in terms of different magnitudes of extreme precipitation, while the stations with significantly positive trends are mainly distributed in the vicinity of the mainstream and major tributaries as well as large lakes, this would result in more tremendous flood disasters in the mid-lower reaches of YRB, especially in southeast coastal regions. The increasing/decreasing linear trends based on annual maximum precipitation are also investigated in pre- and aftclimatic periods, respectively, whereas those changes are not significantly similar to the variations of return values during both subperiods. Moreover, spatiotemporal patterns of precipitation extremes become more uneven and unstable in the second half period over YRB.

  10. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Wilson, J.F.; Sherwood, D.G.

    1982-01-01

    A mechanical spectral shift reactor comprises a reactive core having fuel assemblies accommodating both water displacer elements and neutron absorbing control rods for selectively changing the volume of water-moderator in the core. The fuel assemblies with displacer and control rods are arranged in alternating fashion so that one displacer element drive mechanism may move displacer elements in more than one fuel assembly without interfering with the movement of control rods of a corresponding control rod drive mechanisms. (author)

  11. Neoclassical transport in ERS regime

    International Nuclear Information System (INIS)

    Lin, Z.; Tang, W.; Lee, W.W.

    1996-01-01

    The core ion thermal conductivity has been observed to fall below the standard neoclassical level in recent TFTR reversed magnetic shear discharges. Due to the combination of high central q and small local inverse aspect ratio, the ion poloidal gyroradius can be larger than the minor radius and comparable to the pressure gradient scale length in this ERS regime. It is then expected that finite orbit width effects play a key role in modifying the standard picture of neoclassical transport. Specifically, both the trapped particle fraction and the banana orbit width axe reduced by the finite minor radius and possibly by the pressure-gradient-driven radial electric field. In addition, the steep pressure gradient can generate neoclassical poloidal flows which, in turn, could reduce the particle and heat transports. Results from analytic estimates as well as those from full toroidal gyrokinetic neoclassical simulations will be presented

  12. Unitary Housing Regimes in Transition

    DEFF Research Database (Denmark)

    Bengtsson, Bo; Jensen, Lotte

    2013-01-01

    Path dependence is strong in housing institutions and policy. In both Denmark and Sweden, today’s universal and ‘unitary’ (Kemeny) housing regimes can be traced back to institutions that were introduced fifty years back in history or more. Recently, universal and unitary housing systems...... in Scandinavia, and elsewhere, are under challenge from strong political and economic forces. These challenges can be summarized as economic cutbacks, privatization and Europeanization. Although both the Danish and the Swedish housing system are universal and unitary in character, they differ considerably...... in institutional detail. Both systems have corporatist features, however in Denmark public housing is based on local tenant democracy and control, and in Sweden on companies owned and controlled by the municipalities, combined with a centralized system of rent negotiations. In the paper the present challenges...

  13. Reassessing the nuclear liability regime

    International Nuclear Information System (INIS)

    Havinh Phuong

    1985-01-01

    The nuclear liability regime was thoroughly reviewed by nuclear plant operators, officials of regulatory authorities, and legal and insurance experts at the Symposium on Nuclear Third Party Liability and Insurance, held in September 1984 in Munich, Federal Republic of Germany. The symposium highlighted specific areas where adjustments or improvements would be needed in order to cope with practical problems encountered or emerging issues. By focusing on questions of legitimate concern to the public, it also sought to promote confidence in a compensation system for public protection that is in many ways unique. Topics addressed included the following: greater harmonization of the compensation amounts for nuclear damage established in different countries and in territorial scope; the concept of unlimited liability; the time limitation for compensation claims; the problem of proving causation; the concept of nuclear damage; and insurance coverage

  14. Hall effect in hopping regime

    International Nuclear Information System (INIS)

    Avdonin, A.; Skupiński, P.; Grasza, K.

    2016-01-01

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  15. Hall effect in hopping regime

    Energy Technology Data Exchange (ETDEWEB)

    Avdonin, A., E-mail: avdonin@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Skupiński, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Grasza, K. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Institute of Electronic Materials Technology, ul. Wólczyńska 133, 01-919 Warszawa (Poland)

    2016-02-15

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  16. Early Detection and Identification of Anomalies in Chemical Regime

    International Nuclear Information System (INIS)

    Figedy, Stefan; Smiesko, Ivan

    2011-01-01

    This paper provides a brief information about the basic features of a newly developed diagnostic system for early detection and identification of anomalies incoming in the water chemistry regime of the primary and secondary circuit of VVER-440 reactor. This system, called SACHER (System of Analysis of CHEmical Regime) is being installed within the major modernization project at the NPP-V2 Bohunice in the Slovak Republic. System SACHER has been developed fully in MATLAB environment. The availability of prompt information about the chemical conditions of the primary and secondary circuit is very important to prevent the undue corrosion and deposit build-up. The typical chemical information systems that exist and work at the NPPs give the user values of the measured quantities together with their time trends and other derived values. It is then the experienced user's role to recognize the situation the monitored process is in and make the subsequent decisions and take the measures. The SACHER system, based on the computational intelligence techniques, inserts the elements of intelligence into the overall chemical information system. It has the modular structure with the following most important modules: normality module- its aim is to recognize that the process starts to deviate from the normal one and serves as the early warning to the staff to take the adequate measures, fuzzy identification module- its aim is to identify the anomaly on the basis of a set of fuzzy rules, time-prediction module- its aim is to predict the behavior/trend of selected chemical quantities 8 hours ahead in 15 min step from the moment of request, validation module- its aim is to validate the measured quantities, trend module- this module serves for showing the trends of the acquired quantities

  17. Analytical theory for the nuclear level shift of hadronic atoms

    International Nuclear Information System (INIS)

    Kudryavtsev, A.E.; Lisin, V.I.; Popov, V.S.

    1982-01-01

    The spectrum problem in the Coulomb potential distorted at small distances is considered. Nuclear shifts of 3-levels in p anti p and Σ - p atoms are calculated. The probabilities of radiative transitions from p-states to the shifted s-states in hadronic atom are also given. It is shown that the reconstruction of atomic levels switches to oscillation regime when absorption increases. The limits of applicability of the perturbation theory in terms of the scattering length for different values of absorption is discussed. An exactly solvable model, Coulomb plus Yamaguchi potential, is considered

  18. Accommodating human values in the climate regime

    Directory of Open Access Journals (Sweden)

    Rosalind Cook

    2008-12-01

    Full Text Available The climate regime addresses one of the most important challenges facing humankind today. However, while the environmental and economic sides of the problem are well represented, it lacks the inclusion of social and human aspects. The human rights regime, in contrast, is a regime which has been established precisely to implement human values. This article ex-plains the problems of climate change in terms of human values and argues that some proce-dures from the human rights regime offer possibilities for improvement. It is submitted that through the inclusion of human rights instruments, such as individual communication, pro-gressive realisation and authoritative interpretation, the inclusion of human values into the climate regime will be facilitated. This article presents these instruments and discusses their potential for inclusion in the climate regime.

  19. De Facto Regimes in International Law

    OpenAIRE

    Essen, Jonte van

    2012-01-01

    The ambiguous position of de facto regimes in international law has long been the subject of scholarly debate and a source of political conflict. An assessment of the current standing of these regimes in international law and the consequences of actions by international actors on this status has, however, been long overdue. The manner in which de facto regimes are regarded internationally has serious consequences for the individuals under the influence of this legal grey area. Therefore, the ...

  20. Impacts of precipitation and temperature trends on different time scales on the water cycle and water resource availability in mountainous Mediterranean catchments.

    Science.gov (United States)

    José Pérez-Palazón, María; Pimentel, Rafael; Herrero, Javier; José Polo, María

    2017-04-01

    increase. From the analyses of river flow observations and hydrological modelling, these trends result in an estimated decreasing annual trend of the mean river inflow to reservoirs of 0.091 m3/s, which is equivalent to a mean loss of 2.87 hm3/year during the study period. Nonetheless, these results are associated to a high variability of both extreme values and the annual and decadal values. Moreover, the decrease of the annual inflow is approximately a 25% higher than the loss of precipitation, due to the impact on the different water fluxes from the snowpack associated to the enhanced torrential behaviour of both snowfall/rainfall occurrence and snow persistence. The results show the complexity of hydrological processes in Mediterranean regions, especially under the snow influence, and point out to a significant shift in the precipitation and temperature regime, and thus on the snow-affected hydrological variables in the study area, with a decrease of the available water resource volume in the medium and long term. However, on an annual basis, years with an intense snowfall regime but mild and longer dry periods result in a significant increase of the annual river flow and water storage. Reservoir operation criteria and water allocation should undergo a revision based on hydrological modelling of the snow regions and scenario analysis.

  1. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Doshi, P.K.; George, R.A.; Dollard, W.J.

    1982-01-01

    A mechanical spectral shift arrangement for controlling a nuclear reactor includes a plurality of reactor coolant displacer members which are inserted into a reactor core at the beginning of the core life to reduce the volume of reactor coolant-moderator in the core at start-up. However, as the reactivity of the core declines with fuel depletion, selected displacer members are withdrawn from the core at selected time intervals to increase core moderation at a time when fuel reactivity is declining. (author)

  2. Spectral shift reactor

    International Nuclear Information System (INIS)

    Carlson, W.R.; Piplica, E.J.

    1982-01-01

    A spectral shift pressurized water reactor comprising apparatus for inserting and withdrawing water displacer elements having differing neutron absorbing capabilities for selectively changing the water-moderator volume in the core thereby changing the reactivity of the core. The displacer elements comprise substantially hollow cylindrical low neutron absorbing rods and substantially hollow cylindrical thick walled stainless rods. Since the stainless steel displacer rods have greater neutron absorbing capability, they can effect greater reactivity change per rod. However, by arranging fewer stainless steel displacer rods in a cluster, the reactivity worth of the stainless steel displacer rod cluster can be less than a low neutron absorbing displacer rod cluster. (author)

  3. Proliferation Control Regimes: Background and Status

    National Research Council Canada - National Science Library

    Nikitin, Mary B; Kerr, Paul; Bowman, Steve; Hildreth, Steven A

    2008-01-01

    .... national security interests. Multilateral regimes were established to restrict trade in nuclear, chemical, and biological weapons and missile technologies, and to monitor their civil applications...

  4. Proliferation Control Regimes: Background and Status

    National Research Council Canada - National Science Library

    Squassoni, Sharon; Bowman, Steve; Hildreth, Steven A

    2006-01-01

    .... national security interests. Multilateral regimes were established to restrict trade in nuclear, chemical, and biological weapons and missile technologies, and to monitor their civil applications...

  5. Transforming Water Supply Regimes in India: Do Public-Private Partnerships Have a Role to Play?

    Directory of Open Access Journals (Sweden)

    Govind Gopakumar

    2010-10-01

    Full Text Available Public-private partnerships (PPP are an important governance strategy that has recently emerged as a solution to enhance the access of marginalised residents to urban infrastructures. With the inception of neo-liberal economic reforms in India, in Indian cities too PPP has emerged as an innovative approach to expand coverage of water supply and sanitation infrastructures. However, there has been little study of the dynamics of partnership efforts in different urban contexts: What role do they play in transforming existing infrastructure regimes? Do reform strategies such as partnerships result in increased privatisation or do they make the governance of infrastructures more participative? Reviewing some of the recent literature on urban political analysis, this article develops the concept of water supply regime to describe the context of water provision in three metropolitan cities in India. To further our understanding of the role of PPP within regimes, this article sketches five cases of water supply and sanitation partnerships located within these three metropolitan cities. From these empirical studies, the article arrives at the conclusion that while PPP are always products of the regime-context they are inserted within, quite often strategic actors in the partnership use the PPP to further their interests by initiating a shift in the regime pathway. This leads us to conclude that PPPs do play a role in making water supply regimes more participative but that depends on the nature of the regime as well as the actions of partners.

  6. Competing fiscal regimes and incentives in the developing world

    International Nuclear Information System (INIS)

    Meurs, P. van

    1991-01-01

    The new order in the former Communist countries, the growth of deregulation and trade liberalization, and the opening up of formerly closed countries to outside investment have worked to increase the available exploratory acreage for the oil and gas industry. It is estimated that the total amount of this acreage available in the 1990s is about twice what it was in the 1970s. This is accompanied by an apparent trend toward lower government takes and better terms as governments are forced to compete with one another to attract investment. A particular trend is noted among governments to improve terms and conditions for what are internationally called small fields (those in the 10-30 million bbl class) and in deep water or other marginal conditions. Factors to be taken into account in evaluating the potential profitability of an investment in a developing country are discussed. Various types of fiscal systems are considered, including regressive regimes involving royalties and rentals, progressive features such as sliding royalties and taxes which increase as the field becomes more profitable, hybrid systems, and specialty incentives. Examples are presented to illustrate analyses of different fiscal regimes and the economic risk involved in an oil production investment. 6 tabs

  7. BGK-type models in strong reaction and kinetic chemical equilibrium regimes

    International Nuclear Information System (INIS)

    Monaco, R; Bianchi, M Pandolfi; Soares, A J

    2005-01-01

    A BGK-type procedure is applied to multi-component gases undergoing chemical reactions of bimolecular type. The relaxation process towards local Maxwellians, depending on mass and numerical densities of each species as well as common velocity and temperature, is investigated in two different cases with respect to chemical regimes. These cases are related to the strong reaction regime characterized by slow reactions, and to the kinetic chemical equilibrium regime where fast reactions take place. The consistency properties of both models are stated in detail. The trend to equilibrium is numerically tested and comparisons for the two regimes are performed within the hydrogen-air and carbon-oxygen reaction mechanism. In the spatial homogeneous case, it is also shown that the thermodynamical equilibrium of the models recovers satisfactorily the asymptotic equilibrium solutions to the reactive Euler equations

  8. Repetition and Translation Shifts

    Directory of Open Access Journals (Sweden)

    Simon Zupan

    2006-06-01

    Full Text Available Repetition manifests itself in different ways and at different levels of the text. The first basic type of repetition involves complete recurrences; in which a particular textual feature repeats in its entirety. The second type involves partial recurrences; in which the second repetition of the same textual feature includes certain modifications to the first occurrence. In the article; repetitive patterns in Edgar Allan Poe’s short story “The Fall of the House of Usher” and its Slovene translation; “Konec Usherjeve hiše”; are compared. The author examines different kinds of repetitive patterns. Repetitions are compared at both the micro- and macrostructural levels. As detailed analyses have shown; considerable microstructural translation shifts occur in certain types of repetitive patterns. Since these are not only occasional; sporadic phenomena; but are of a relatively high frequency; they reduce the translated text’s potential for achieving some of the gothic effects. The macrostructural textual property particularly affected by these shifts is the narrator’s experience as described by the narrative; which suffers a reduction in intensity.

  9. Shift Work: Improving Daytime Sleep

    Science.gov (United States)

    ... night. Good daytime sleep is possible, though, if shift work is a necessary part of your work life. ... mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/shift-work/faq-20057991 . Mayo Clinic Footer Legal Conditions and ...

  10. Rotating night shift work, sleep, and colorectal adenoma in women.

    Science.gov (United States)

    Devore, Elizabeth E; Massa, Jennifer; Papantoniou, Kyriaki; Schernhammer, Eva S; Wu, Kana; Zhang, Xuehong; Willett, Walter C; Fuchs, Charles S; Chan, Andrew T; Ogino, Shuji; Giovannucci, Edward; Wei, Esther K

    2017-07-01

    This study aims to investigate the associations of rotating night shift work history and sleep duration with risk of colorectal adenoma. We evaluated 56,275 cancer-free participants of the Nurses' Health Study II, who had their first colonoscopy or sigmoidoscopy between 1991 and 2011; rotating night shift work and sleep duration were reported by mailed questionnaire. Multivariable-adjusted logistic regression was used to estimate relative risks (RR) of colorectal adenoma, with 95% confidence intervals (CI), across categories of rotating night shift work history (none, 1-4, 5-9, and ≥10 years) and sleep duration (≤5, 6, 7, 8, and ≥9 h/day). We found no association between duration of rotating night shift work and occurrence of colorectal adenoma (p-trend across shift work categories = 0.5). Women with the longest durations of rotating night shift work (≥10 years) had a similar risk of adenoma compared to women without a history of rotating night shift work (multivariable-adjusted RR = 0.96, 95% CI = 0.83-1.11). Similarly, there were no associations of shorter or longer sleep durations with adenoma risk (p-trend = 0.2 across sleep durations of ≤5 through 7 h/day and p-trend = 0.5 across sleep durations of 7 through ≥9 h/day). Results were similar when we examined associations according to adenoma location and subtype. Our results do not support an association between rotating night shift work or sleep duration and risk of colorectal adenoma in women.

  11. Online Marketing Trends

    OpenAIRE

    Horecká, Ivana

    2015-01-01

    This thesis deals with online marketing trends. Its main goal is to define the latest online marketing trends, create a website with the free online marketing trends, and analyse their effectiveness. The theoretical part brings a thorough description of the latest online marketing trends. Moreover, it provides an insight into the latest trends in the website development. The chosen online marketing trends defined in the theoretical part are subsequently applied on a newly created website. All...

  12. Lanthanide shift reagents, binding, shift mechanisms and exchange

    International Nuclear Information System (INIS)

    Boer, J.W.M. de

    1977-01-01

    Paramagnetic lanthanide shift reagents, when added to a solution of a substrate, induce shifts in the nuclear magnetic resonance (NMR) spectrum of the substrate molecules. The induced shifts contain information about the structure of the shift reagent substrate complex. The structural information, however, may be difficult to extract because of the following effects: (1) different complexes between shift reagent and substrate may be present in solution, e.g. 1:1 and 1:2 complexes, and the shift observed is a weighed average of the shifts of the substrate nuclei in the different complexes; (2) the Fermi contact interaction, arising from the spin density at the nucleus, contributes to the induced shift; (3) chemical exchange effects may complicate the NMR spectrum. In this thesis, the results of an investigation into the influence of these effects on the NMR spectra of solutions containing a substrate and LSR are presented. The equations describing the pseudo contact and the Fermi contact shift are derived. In addition, it is shown how the modified Bloch equations describing the effect of the chemical exchange processes occurring in the systems studied can be reduced to the familiar equations for a two-site exchange case. The binding of mono- and bifunctional ethers to the shift reagent are reported. An analysis of the induced shifts is given. Finally, the results of the experiments performed to study the exchange behavior of dimethoxyethane and heptafluorodimethyloctanedionato ligands are presented

  13. How the origin of organic compounds affects vegetation patchiness and regime shifts in ecosystems

    NARCIS (Netherlands)

    Dekker, S.C.; Nierop, K.G.J.; Mao, J.

    2012-01-01

    Soil water repellency (SWR) is a common property of soils and has been reported from all inhabited continents. It can have negative consequences for plant growth due to stagnation of water infiltration. Recently, the understanding of SWR has increased, mainly for the soil physical mechanisms.

  14. Smart social adaptation prevents catastrophic ecological regime shifts in networks of myopic harvesters

    Science.gov (United States)

    Donges, Jonathan; Lucht, Wolfgang; Wiedermann, Marc; Heitzig, Jobst; Kurths, Jürgen

    2015-04-01

    In the anthropocene, the rise of global social and economic networks with ever increasing connectivity and speed of interactions, e.g., the internet or global financial markets, is a key challenge for sustainable development. The spread of opinions, values or technologies on these networks, in conjunction with the coevolution of the network structures themselves, underlies nexuses of current concern such as anthropogenic climate change, biodiversity loss or global land use change. To isolate and quantitatively study the effects and implications of network dynamics for sustainable development, we propose an agent-based model of information flow on adaptive networks between myopic harvesters that exploit private renewable resources. In this conceptual model of a network of socio-ecological systems, information on management practices flows between agents via boundedly rational imitation depending on the state of the resource stocks involved in an interaction. Agents can also adapt the structure of their social network locally by preferentially connecting to culturally similar agents with identical management practices and, at the same time, disconnecting from culturally dissimilar agents. Investigating in detail the statistical mechanics of this model, we find that an increasing rate of information flow through faster imitation dynamics or growing density of network connectivity leads to a marked increase in the likelihood of environmental resource collapse. However, we show that an optimal rate of social network adaptation can mitigate this negative effect without loss of social cohesion through network fragmentation. Our results highlight that seemingly immaterial network dynamics of spreading opinions or values can be of large relevance for the sustainable management of socio-ecological systems and suggest smartly conservative network adaptation as a strategy for mitigating environmental collapse. Hence, facing the great acceleration, these network dynamics should be more routinely incorporated in standard models of economic development or integrated assessment models used for evaluating anthropogenic climate change.

  15. Wavelet decomposition and regime shifts. Assessing the effects of crude oil shocks on stock market returns

    Energy Technology Data Exchange (ETDEWEB)

    Jammazi, Rania; Aloui, Chaker [International finance group-Tunisia, Faculty of Management and Economic Sciences of Tunis, Boulevard du 7 novembre, El Manar University, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia)

    2010-03-15

    While there is a large body of empirical studies on the relationship between crude oil price changes and stock market returns, they have failed to achieve a consensus on this subject. In this paper, we combine wavelet analysis and Markov Switching Vector Autoregressive (MS-VAR) approach to explore the impact of the crude oil (CO) shocks on the stock market returns for UK, France and Japan over the period from January 1989 to December 2007. Our procedure involves the estimation of the extended MS-VAR model in order to investigate the importance of the resultant wavelet filtering series (after removing random components) in determining the behavior of the stock market volatilities. We show that CO shocks do not affect the recession stock market phases (except for Japan). However, they significantly reduce moderate and/or expansion stock market phases temporarily. Moreover, this negative relationship appears to be more pronounced during the pre-1999 period. The empirical findings will prove extremely useful to investors who need to understand the exact effect of international oil changes on certain stocks prices as well as for policy managers who need a more thorough evaluation about the efficiency of hedging policies affected by oil price changes. (author)

  16. Wavelet decomposition and regime shifts: Assessing the effects of crude oil shocks on stock market returns

    Energy Technology Data Exchange (ETDEWEB)

    Jammazi, Rania, E-mail: jamrania2@yahoo.f [International finance group-Tunisia, Faculty of Management and Economic Sciences of Tunis, Boulevard du 7 novembre, El Manar University, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia); Aloui, Chaker, E-mail: chaker.aloui@fsegt.rnu.t [International finance group-Tunisia, Faculty of Management and Economic Sciences of Tunis, Boulevard du 7 novembre, El Manar University, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia)

    2010-03-15

    While there is a large body of empirical studies on the relationship between crude oil price changes and stock market returns, they have failed to achieve a consensus on this subject. In this paper, we combine wavelet analysis and Markov Switching Vector Autoregressive (MS-VAR) approach to explore the impact of the crude oil (CO) shocks on the stock market returns for UK, France and Japan over the period from January 1989 to December 2007. Our procedure involves the estimation of the extended MS-VAR model in order to investigate the importance of the resultant wavelet filtering series (after removing random components) in determining the behavior of the stock market volatilities. We show that CO shocks do not affect the recession stock market phases (except for Japan). However, they significantly reduce moderate and/or expansion stock market phases temporarily. Moreover, this negative relationship appears to be more pronounced during the pre-1999 period. The empirical findings will prove extremely useful to investors who need to understand the exact effect of international oil changes on certain stocks prices as well as for policy managers who need a more thorough evaluation about the efficiency of hedging policies affected by oil price changes.

  17. Regime shifts and weakened environmental gradients in open oak and pine ecosystems

    Science.gov (United States)

    Brice B. Hanberry; Dan C. Dey; Hong S. He

    2012-01-01

    Fire suppression allows tree species that are intolerant of fire stress to increase their distribution, potentially resulting in disruption of historical species-environmental relationships. To measure changes between historical General Land Office surveys (1815 to 1850) and current USDA Forest Inventory and Assessment surveys (2004 to 2008), we compared composition,...

  18. Tropical Atlantic climate and ecosystem regime shifts during the Paleocene-Eocene Thermal Maximum

    Science.gov (United States)

    Frieling, Joost; Reichart, Gert-Jan; Middelburg, Jack J.; Röhl, Ursula; Westerhold, Thomas; Bohaty, Steven M.; Sluijs, Appy

    2018-01-01

    The Paleocene-Eocene Thermal Maximum (PETM, 56 Ma) was a phase of rapid global warming associated with massive carbon input into the ocean-atmosphere system from a 13C-depleted reservoir. Many midlatitude and high-latitude sections have been studied and document changes in salinity, hydrology and sedimentation, deoxygenation, biotic overturning, and migrations, but detailed records from tropical regions are lacking. Here, we study the PETM at Ocean Drilling Program (ODP) Site 959 in the equatorial Atlantic using a range of organic and inorganic proxies and couple these with dinoflagellate cyst (dinocyst) assemblage analysis. The PETM at Site 959 was previously found to be marked by a ˜ 3.8 ‰ negative carbon isotope excursion (CIE) and a ˜ 4 °C surface ocean warming from the uppermost Paleocene to peak PETM, of which ˜ 1 °C occurs before the onset of the CIE. We record upper Paleocene dinocyst assemblages that are similar to PETM assemblages as found in extratropical regions, confirming poleward migrations of ecosystems during the PETM. The early stages of the PETM are marked by a typical acme of the tropical genus Apectodinium, which reaches abundances of up to 95 %. Subsequently, dinocyst abundances diminish greatly, as do carbonate and pyritized silicate microfossils. The combined paleoenvironmental information from Site 959 and a close-by shelf site in Nigeria implies the general absence of eukaryotic surface-dwelling microplankton during peak PETM warmth in the eastern equatorial Atlantic, most likely caused by heat stress. We hypothesize, based on a literature survey, that heat stress might have reduced calcification in more tropical regions, potentially contributing to reduced deep sea carbonate accumulation rates, and, by buffering acidification, also to biological carbonate compensation of the injected carbon during the PETM. Crucially, abundant organic benthic foraminiferal linings imply sustained export production, likely driven by prokaryotes. In sharp contrast, the recovery of the CIE yields rapid (≪ 10 kyr) fluctuations in the abundance of several dinocyst groups, suggesting extreme ecosystem and environmental variability.

  19. Regime shifts and weakened environmental gradients in open oak and pine ecosystems.

    Science.gov (United States)

    Hanberry, Brice B; Dey, Dan C; He, Hong S

    2012-01-01

    Fire suppression allows tree species that are intolerant of fire stress to increase their distribution, potentially resulting in disruption of historical species-environmental relationships. To measure changes between historical General Land Office surveys (1815 to 1850) and current USDA Forest Inventory and Assessment surveys (2004 to 2008), we compared composition, distribution, and site factors of 21 tree species or species groups in the Missouri Ozarks. We used 24 environmental variables and random forests as a classification method to model distributions. Eastern redcedar, elms, maples, and other fire-sensitive species have increased in dominance in oak forests, with concurrent reductions by oak species; specific changes varied by ecological subsection. Ordinations displayed loss of separation between formerly distinctive oak and fire-sensitive tree species groups. Distribution maps showed decreased presence of disturbance-dependent oak and pine species and increased presence of fire-sensitive species that generally expanded from subsections protected from fire along rivers to upland areas, except for eastern redcedar, which expanded into these subsections. Large scale differences in spatial gradients between past and present communities paralleled reduced influence of local topographic gradients in the varied relief of the Missouri Ozarks, as fire-sensitive species have moved to higher, drier, and sunnier sites away from riverine corridors. Due to changes in land use, landscapes in the Missouri Ozarks, eastern United States, and world-wide are changing from open oak and pine-dominated ecosystems to novel oak-mixed species forests, although at fine scales, forests are becoming more diverse in tree species today. Fire suppression weakened the influence by environmental gradients over species dominance, allowing succession from disturbance-dependent oaks to an alternative state of fire-sensitive species. Current and future research and conservation that rely on historical relationships and ecological principles based on disturbance across the landscape will need to incorporate modern interactions among species for resources into management plans and projections.

  20. Regime shifts and weakened environmental gradients in open oak and pine ecosystems.

    Directory of Open Access Journals (Sweden)

    Brice B Hanberry

    Full Text Available Fire suppression allows tree species that are intolerant of fire stress to increase their distribution, potentially resulting in disruption of historical species-environmental relationships. To measure changes between historical General Land Office surveys (1815 to 1850 and current USDA Forest Inventory and Assessment surveys (2004 to 2008, we compared composition, distribution, and site factors of 21 tree species or species groups in the Missouri Ozarks. We used 24 environmental variables and random forests as a classification method to model distributions. Eastern redcedar, elms, maples, and other fire-sensitive species have increased in dominance in oak forests, with concurrent reductions by oak species; specific changes varied by ecological subsection. Ordinations displayed loss of separation between formerly distinctive oak and fire-sensitive tree species groups. Distribution maps showed decreased presence of disturbance-dependent oak and pine species and increased presence of fire-sensitive species that generally expanded from subsections protected from fire along rivers to upland areas, except for eastern redcedar, which expanded into these subsections. Large scale differences in spatial gradients between past and present communities paralleled reduced influence of local topographic gradients in the varied relief of the Missouri Ozarks, as fire-sensitive species have moved to higher, drier, and sunnier sites away from riverine corridors. Due to changes in land use, landscapes in the Missouri Ozarks, eastern United States, and world-wide are changing from open oak and pine-dominated ecosystems to novel oak-mixed species forests, although at fine scales, forests are becoming more diverse in tree species today. Fire suppression weakened the influence by environmental gradients over species dominance, allowing succession from disturbance-dependent oaks to an alternative state of fire-sensitive species. Current and future research and conservation that rely on historical relationships and ecological principles based on disturbance across the landscape will need to incorporate modern interactions among species for resources into management plans and projections.

  1. Immune Boosting Explains Regime-Shifts in Prevaccine-Era Pertussis Dynamics

    DEFF Research Database (Denmark)

    Lavine, Jennie; King, Aaron A; Andreasen, Viggo

    2013-01-01

    Understanding the biological mechanisms underlying episodic outbreaks of infectious diseases is one of mathematical epidemiology’s major goals. Historic records are an invaluable source of information in this enterprise. Pertussis (whooping cough) is a re-emerging infection whose intermittent bouts...... with permanent or passively-waning immunity. Our results emphasize the importance of understanding the mechanisms responsible for maintaining immune memory for pertussis epidemiology....

  2. Early warning signals of regime shifts from cross-scale connectivity of land-cover patterns

    Science.gov (United States)

    Giovanni Zurlini; Kenneth Bruce Jones; Kurt Hans Riitters; Bai-Lian Li; Irene Petrosillo

    2014-01-01

    Increasing external pressures from human activities and climate change can lead to desertification, affecting the livelihood of more than 25% of the world’s population. Thus, determining proximity to transition to desertification is particularly central for arid regions before they may convert into deserts, and recent research has focused on devising early warning...

  3. Dynamic Analytical Capability to Better Understand and Anticipate Extremist Shifts Within Populations under Authoritarian Regimes.

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Michael Lewis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    The purpose of this work is to create a generalizable data- and theory-supported capability to better understand and anticipate (with quantifiable uncertainty): 1) how the dynamics of allegiance formations between various groups and society are impacted by active conflict and by third-party interventions and 2) how/why extremist allegiances co-evolve over time due to changing geopolitical, sociocultural, and military conditions.

  4. Regime shifts in shallow lakes: the importance of seasonal fish migration

    DEFF Research Database (Denmark)

    Brönmark, Christer; Brodersen, Jakob; Chapman, Ben B.

    2010-01-01

    . Our earlier research shows that a large proportion of zooplanktivorous fish populations in shallow lakes undertake seasonal migrations where they leave the lake during winter and migrate back to the lake in spring. Based on our past research, we propose a number of scenarios of how feedback processes...... properties, including piscivore abundance and zooplankton productivity, affect the individual state of zooplanktivorous fish, such as growth rate or condition. Individual state, in turn, affects the relative proportion and timing of migrating zooplanktivorous fish. This change, in turn, may stabilize states...... between the individual and ecosystem levels may affect stability of alternative stable states in shallow lakes when mediated by fish migration. Migration effects on shallow lakes result from processes at different scales, from the individual to the ecosystem. Our earlier research has shown that ecosystem...

  5. Base flow-driven shifts in tropical stream temperature regimes across a mean annual rainfall gradient

    Science.gov (United States)

    Ayron M. Strauch; Richard A. MacKenzie; Ralph W. Tingley

    2017-01-01

    Climate change is expected to affect air temperature and watershed hydrology, but the degree to which these concurrent changes affect stream temperature is not well documented in the tropics. How stream temperature varies over time under changing hydrologic conditions is difficult to isolate from seasonal changes in air temperature. Groundwater and bank storage...

  6. Wavelet decomposition and regime shifts: Assessing the effects of crude oil shocks on stock market returns

    International Nuclear Information System (INIS)

    Jammazi, Rania; Aloui, Chaker

    2010-01-01

    While there is a large body of empirical studies on the relationship between crude oil price changes and stock market returns, they have failed to achieve a consensus on this subject. In this paper, we combine wavelet analysis and Markov Switching Vector Autoregressive (MS-VAR) approach to explore the impact of the crude oil (CO) shocks on the stock market returns for UK, France and Japan over the period from January 1989 to December 2007. Our procedure involves the estimation of the extended MS-VAR model in order to investigate the importance of the resultant wavelet filtering series (after removing random components) in determining the behavior of the stock market volatilities. We show that CO shocks do not affect the recession stock market phases (except for Japan). However, they significantly reduce moderate and/or expansion stock market phases temporarily. Moreover, this negative relationship appears to be more pronounced during the pre-1999 period. The empirical findings will prove extremely useful to investors who need to understand the exact effect of international oil changes on certain stocks prices as well as for policy managers who need a more thorough evaluation about the efficiency of hedging policies affected by oil price changes.

  7. Tropical Atlantic climate and ecosystem regime shifts during the Paleocene–Eocene Thermal Maximum

    Directory of Open Access Journals (Sweden)

    J. Frieling

    2018-01-01

    Full Text Available The Paleocene–Eocene Thermal Maximum (PETM, 56 Ma was a phase of rapid global warming associated with massive carbon input into the ocean–atmosphere system from a 13C-depleted reservoir. Many midlatitude and high-latitude sections have been studied and document changes in salinity, hydrology and sedimentation, deoxygenation, biotic overturning, and migrations, but detailed records from tropical regions are lacking. Here, we study the PETM at Ocean Drilling Program (ODP Site 959 in the equatorial Atlantic using a range of organic and inorganic proxies and couple these with dinoflagellate cyst (dinocyst assemblage analysis. The PETM at Site 959 was previously found to be marked by a  ∼  3.8 ‰ negative carbon isotope excursion (CIE and a  ∼  4 °C surface ocean warming from the uppermost Paleocene to peak PETM, of which  ∼  1 °C occurs before the onset of the CIE. We record upper Paleocene dinocyst assemblages that are similar to PETM assemblages as found in extratropical regions, confirming poleward migrations of ecosystems during the PETM. The early stages of the PETM are marked by a typical acme of the tropical genus Apectodinium, which reaches abundances of up to 95 %. Subsequently, dinocyst abundances diminish greatly, as do carbonate and pyritized silicate microfossils. The combined paleoenvironmental information from Site 959 and a close-by shelf site in Nigeria implies the general absence of eukaryotic surface-dwelling microplankton during peak PETM warmth in the eastern equatorial Atlantic, most likely caused by heat stress. We hypothesize, based on a literature survey, that heat stress might have reduced calcification in more tropical regions, potentially contributing to reduced deep sea carbonate accumulation rates, and, by buffering acidification, also to biological carbonate compensation of the injected carbon during the PETM. Crucially, abundant organic benthic foraminiferal linings imply sustained export production, likely driven by prokaryotes. In sharp contrast, the recovery of the CIE yields rapid (≪ 10 kyr fluctuations in the abundance of several dinocyst groups, suggesting extreme ecosystem and environmental variability.

  8. Evolutionary regime shifts in age and size at maturation of exploited fish stocks

    Czech Academy of Sciences Publication Activity Database

    de Roos, A. M.; Boukal S., David; Persson, L.

    2006-01-01

    Roč. 1596, č. 273, (2006), s. 1873-1880 ISSN 0962-8452 R&D Projects: GA ČR GP201/02/D088 Institutional research plan: CEZ:AV0Z50070508 Keywords : complex adaptive systems * life-history evolution * ecological feedbacks Subject RIV: ED - Physiology Impact factor: 3.612, year: 2006

  9. Regime shifts and panarchies in regional scale social-ecological water systems

    Science.gov (United States)

    In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive gove...

  10. Faktor Dan Penjadualan Shift Kerja

    OpenAIRE

    Maurits, Lientje Setyawati; Widodo, Imam Djati

    2008-01-01

    Work shift has negative effect in physical and mental health, work performance and job accident. Disturbance of circadian rhythms is indicated as source of the problems. This article explores some researches related to the impacts of work shift and establishes basic principles of work shift scheduling that considers human need and limitation.

  11. Isotope shifting capacity of rock

    International Nuclear Information System (INIS)

    Blattner, P.; Department of Scientific and Industrial Research, Lower Hutt

    1980-01-01

    Any oxygen isotope shifted rock volume exactly defines a past throughput of water. An expression is derived that relates the throughput of an open system to the isotope shift of reservoir rock and present-day output. The small isotope shift of Ngawha reservoir rock and the small, high delta oxygen-18 output are best accounted for by a magmatic water source

  12. Shifting conceptions of complexity in forest management and silviculture

    Science.gov (United States)

    Robert T. Fahey; Brandon C. Alveshere; Julia I. Burton; Anthony W. D' Amato; Yvette L. Dickinson; William S. Keeton; Christel C. Kern; Andrew J. Larson; Brian J. Palik; Klaus J. Puettmann; Michael R. Saunders; Christopher R. Webster; Jeff W. Atkins; Christopher M. Gough; Brady S. Hardiman

    2018-01-01

    In the past several decades, a trend in forestry and silviculture has been toward promoting complexity in forest ecosystems, but how complexity is conceived and described has shifted over time as new ideas and terminology have been introduced. Historically, ecologically-focused silviculture has focused largely on manipulation of structural complexity, but often with...

  13. International arbitration and its exclusion from the Brussels regime

    Directory of Open Access Journals (Sweden)

    Hamed Alavi

    2016-06-01

    Full Text Available The Brussels regime, which regulates the matters of transnational litigation excludes arbitration from its scope. Upon formation of the Brussels regime the existing instruments concerning arbitration - the United Nations Convention on Recognition and Enforcement of Foreign Arbitral Awards and the 1961 European Convention on International Commercial Arbitration - were believed to be sufficient. The original Brussels Convention 1968 on recognition and enforcement of judgments delivered in the courts of the EU Member States expressly provided for the exclusion of arbitration. The following Brussels I Regulation followed the trend and reinforced the exclusion of arbitration from their material scopes. The rationale for doing so was primarily the prevention of parallel proceedings and irreconcilable judgments. The arbitration exclusion from the Brussels regime has caused a fair amount of confusion, especially regarding the extent and limits of the exclusion. That is, whether the arbitration agreement, the arbitral award and its consequences are covered by the exclusion or they may fall under the scope of the Brussels regulation if they constitute only an incidental question to the main cause of action? The confusion was illustrated in the ECJ judgment West Tankers, which generated negative feedback from the arbitration community and indicated the need for reform. The recently adopted Recast Regulation took it upon itself to clarify the relationship between arbitration and the EU regime of transnational litigation. The exclusion is reinforced ye again and its boundaries are specified in the Preamble. However, whether or not the concerns about the extent and objectives of arbitration exclusion have been at present eliminated, remains to be seen.

  14. Social development in cities and the impact of the Nordic welfare regime

    DEFF Research Database (Denmark)

    Christensen, Anders Bøggild; Rasmussen, Tove Valborg; Rasinkangas, Jarkko

    The ongoing globalisation and urbanisation in most Western societies points at the cities and urban regions as especially interesting in order to discover new trends in the societal development and the welfare regimes ability to deal with these trends. In the literature about social polarisation...... it is mostly the so called global cities - and further capital cities - which are in focus of the analysis {{81 Sassen,Saskia 2001; 366 Sassen, Saskia 2000; 85 Castells,Manuel 1991; 86 Mollenkopf,John Hull 1991; 57 Marcuse,Peter 2000; 94 Hamnett,Chris 2003; 409 Andersen,Hans Thor 2005; 410 Wessel, Terje; 411...... Vaattovaara, Mari and Matti Kortteinen 2003}}. Following central thesis of trends in the distributional and spatial development in cities and discussions about the role of the welfare regime, we shall compare two middle sized cities in two Nordic countries: Aarhus, Denmark (approx 300.000 inhabitants...

  15. Capacitance densitometer for flow regime identification

    International Nuclear Information System (INIS)

    Shipp, R.L. Jr.

    1978-01-01

    This invention relates to a capacitance densitometer for determining the flow regime of a two-phase flow system. A two-element capacitance densitometer is used in conjunction with a conventional single-beam gamma densitometer to unambiguously identify the prevailing flow regime and the average density of a flowing fluid

  16. TARIFFS AND REGIMES OF POWER CONSUMPTION

    Directory of Open Access Journals (Sweden)

    S. V. Batsova

    2010-01-01

    Full Text Available Analysis of regimes of electro-consumption at RUP «BMZ» is carried out. It is shown that in conditions of rapid growth of prices for electric power one of the conditions of reduction of production expenses is to be the increase of efficiency of the electro-consumption regimes control.

  17. Strengthening the nuclear non-proliferation regime

    International Nuclear Information System (INIS)

    Carlson, J.

    2003-01-01

    Although the nuclear non-proliferation regime has enjoyed considerable success, today the regime has never been under greater threat. Three states have challenged the objectives of the NPT, and there is a technology challenge - the spread of centrifuge enrichment technology and know-how. A major issue confronting the international community is, how to deal with a determined proliferator? Despite this gloomy scenario, however, the non-proliferation regime has considerable strengths - many of which can be developed further. The regime comprises complex interacting and mutually reinforcing elements. At its centre is the NPT - with IAEA safeguards as the Treaty's verification mechanism. Important complementary elements include: restraint in the supply and the acquisition of sensitive technologies; multilateral regimes such as the CTBT and proposed FMCT; various regional and bilateral regimes; the range of security and arms control arrangements outside the nuclear area (including other WMD regimes); and the development of proliferation-resistant technologies. Especially important are political incentives and sanctions in support of non-proliferation objectives. This paper outlines some of the key issues facing the non-proliferation regime

  18. Synergies between nonproliferation regimes: A pragmatic approach

    International Nuclear Information System (INIS)

    Findlay, Trevor; Meier, Oliver

    2001-01-01

    Full text: With the recent progress in establishing international nonproliferation regimes, the question of synergies between different verification and monitoring regimes is becoming more acute. Three multilateral and universal nonproliferation organisations covering safeguards on civil nuclear materials, nuclear testing, and chemical weapons are up and running. A regime on biological weapons is under negotiation. Several regional organisations concerned with monitoring nonproliferation commitments in the nuclear field are in place; others are being established. Past discussions on synergies between these regimes have suffered from being too far-reaching. These discussions often have not reflected adequately the political difficulties of cooperation between regimes with different membership, scope and institutional set-up. This paper takes a pragmatic look at exploiting synergies and identifies some potential and real overlaps in the work between different verification regimes. It argues for a bottom-up approach and identifies building blocks for collaboration between verification regimes. By realising such, more limited potential for cooperation, the ground could be prepared for exploiting other synergies between these regimes. (author)

  19. The shift in windpower

    International Nuclear Information System (INIS)

    Gipe, P.

    1992-01-01

    Despite new production records, the near-term market for new windpower projects in the US remains bleak. Congressional incentives and project proposals in the mid-1990s offer promise, but for now most development has shifted to Europe. During 1992 and 1993 the largest wind projects developed by US companies will not be in the US, but in the United Kingdom and Spain. Indeed, most of the US's windpower industry is going abroad, establishing offices overseas. This move toward Europe comes as little surprise. New project development for US firms has faltered at home while the European market has burgeoned. The topics of the article include the move to Europe, a reduction in California's share of producing wind power plants, a rise in Europe's share of producing wind power plants, the future market for wind power in the US, and reawakening California's market

  20. The shift of accounting models and accounting quality: the case of Norwegian GAAP

    OpenAIRE

    Stenheim, Tonny; Madsen, Dag Øivind

    2017-01-01

    This is an Open Access journal available from http://www.virtusinterpress.org This paper investigates the change in accounting quality w hen firms shift from a revenue - oriented historical cost accounting regime as Norwegian GAAP (NGAAP) to a balance - oriented fair value accounting regime as International Financial Reporting Standards (IFRS). Previous studies have demonstrated mixed effects o n the accounting quality upon IFRS adoption. One possible reason is that the investigated domest...

  1. Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

    Science.gov (United States)

    Göckede, Mathias; Kittler, Fanny; Kwon, Min Jung; Burjack, Ina; Heimann, Martin; Kolle, Olaf; Zimov, Nikita; Zimov, Sergey

    2017-12-01

    Hydrologic conditions are a key factor in Arctic ecosystems, with strong influences on ecosystem structure and related effects on biogeophysical and biogeochemical processes. With systematic changes in water availability expected for large parts of the northern high-latitude region in the coming centuries, knowledge on shifts in ecosystem functionality triggered by altered water levels is crucial for reducing uncertainties in climate change predictions. Here, we present findings from paired ecosystem observations in northeast Siberia comprising a drained and a control site. At the drainage site, the water table has been artificially lowered by up to 30 cm in summer for more than a decade. This sustained primary disturbance in hydrologic conditions has triggered a suite of secondary shifts in ecosystem properties, including vegetation community structure, snow cover dynamics, and radiation budget, all of which influence the net effects of drainage. Reduced thermal conductivity in dry organic soils was identified as the dominating drainage effect on energy budget and soil thermal regime. Through this effect, reduced heat transfer into deeper soil layers leads to shallower thaw depths, initially leading to a stabilization of organic permafrost soils, while the long-term effects on permafrost temperature trends still need to be assessed. At the same time, more energy is transferred back into the atmosphere as sensible heat in the drained area, which may trigger a warming of the lower atmospheric surface layer.

  2. Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

    Directory of Open Access Journals (Sweden)

    M. Göckede

    2017-12-01

    Full Text Available Hydrologic conditions are a key factor in Arctic ecosystems, with strong influences on ecosystem structure and related effects on biogeophysical and biogeochemical processes. With systematic changes in water availability expected for large parts of the northern high-latitude region in the coming centuries, knowledge on shifts in ecosystem functionality triggered by altered water levels is crucial for reducing uncertainties in climate change predictions. Here, we present findings from paired ecosystem observations in northeast Siberia comprising a drained and a control site. At the drainage site, the water table has been artificially lowered by up to 30 cm in summer for more than a decade. This sustained primary disturbance in hydrologic conditions has triggered a suite of secondary shifts in ecosystem properties, including vegetation community structure, snow cover dynamics, and radiation budget, all of which influence the net effects of drainage. Reduced thermal conductivity in dry organic soils was identified as the dominating drainage effect on energy budget and soil thermal regime. Through this effect, reduced heat transfer into deeper soil layers leads to shallower thaw depths, initially leading to a stabilization of organic permafrost soils, while the long-term effects on permafrost temperature trends still need to be assessed. At the same time, more energy is transferred back into the atmosphere as sensible heat in the drained area, which may trigger a warming of the lower atmospheric surface layer.

  3. Legislative proposal for a controlled foreign companies regime in Poland from an international perspective

    Directory of Open Access Journals (Sweden)

    Magdalena Małgorzata Hybka

    2014-12-01

    Full Text Available Tackling corporate profit shifting requires appropriate anti-avoidance measures. This article reviews one of these measures, a controlled foreign companies (corporations regime. It has been implemented in many countries, in some of them as early as the 1960s. The need for its introduction has also been expressed on many occasions by the Polish legislator. The article is composed of three sections. The first considers the reasons for the implementation of the analyzed regime. The second describes the controlled foreign corporation legislation in the USA and selected European Union member states. The last section is devoted to a bill on taxing controlled foreign companies in Poland.

  4. Relationships between copepod community structure, rainfall regimes, and hydrological variables in a tropical mangrove estuary (Amazon coast, Brazil)

    Science.gov (United States)

    Magalhães, André; Pereira, Luci Cajueiro Carneiro; da Costa, Rauquírio Marinho

    2015-03-01

    The influence of rainfall and hydrological variables on the abundance and diversity of the copepod community was investigated on a monthly basis over an annual cycle in the Taperaçu mangrove estuary. In general, the results show that there were no clear spatial or tidal patterns in any biological variables during the study period, which was related to the reduced horizontal gradient in abiotic parameters, determined mainly by the morphological and morphodynamic features of the estuary. Nevertheless, seasonal and monthly trends were recorded in both the hydrological data and the abundance of the dominant copepod species. In particular, Pseudodiaptomus marshi (6,004.6 ± 22,231.6 ind m-3; F = 5.0, p < 0.05) and Acartia tonsa (905.6 ± 2,400.9 ind m-3; F = 14.6, p < 0.001) predominated during the rainy season, whereas Acartia lilljeborgii (750.8 ± 808.3 ind m-3; U = 413.0, p < 0.01) was the most abundant species in the dry season. A distinct process of succession was observed in the relative abundance of these species, driven by the shift in the rainfall regime, which affected hydrological, in particular salinity, and consequently the abundance of copepod species. We suggest that this may be a general pattern governing the dynamics of copepod populations in the estuaries of the Brazilian Amazonian region.

  5. Pluton emplacement in a releasing bend in a transpressive regime: the arrozal granite in the Paraíba do Sul shear belt, Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Alexis R. Nummer

    2007-06-01

    Full Text Available The Arrozal Granite, situated in the southwestern region of the State of Rio de Janeiro, has a granitic to granodioritic composition. It contains a strong mylonitic foliation along its border, passing gradually to a well-developed magmatic foliation towards its center. Structural analysis indicates that the Arrozal Granite was emplaced along the Além-Paraíba Shear Zone in a dextral transpressive tectonic regime. A regional shift of the trend along this shear zone from NE-SW to E-W, observed in the area, is interpreted to be casually related to the creation of space for the emplacement of the granite. Our data indicate that releasing bends may have played an important role for space generation during the emplacement of the Arrozal Granite and other plutons.O Granito Arrozal ocorre na porção sudoeste do Estado do Rio de Janeiro e associa-se à Zona de Cisalhamento de Além-Paraíba. Possui composição granítica a granodiorítica eexibe predomínio de estruturas magmáticas na parte central, e estruturas de alto strain (miloníticas nas bordas. Os dados estruturais sugerem colocação em segmentos extensionais(releasing bends associados a uma tectônica transcorrentedestral, sob regime transpressivo. A forte mudança do trend estrutural desta zona de cisalhamento na região, passando de NE-SW para próximo de E-W, criou condições para geração de espaços que favoreceram a colocação do Granito Arrozal, além de outros granitos associados à referida zona.

  6. The collective Lamb shift in nuclear γ-ray superradiance

    International Nuclear Information System (INIS)

    Röhlsberger, Ralf

    2012-01-01

    The electromagnetic transitions of Mössbauer nuclei provide almost ideal two-level systems to transfer quantum optical concepts into the regime of hard x-rays. If many identical atoms collectively interact with a resonant radiation field, one observes (quantum) optical properties that are strongly different from those of a single atom. The most prominent effect is the broadening of the resonance line known as collective enhancement, resulting from multiple scattering of real photons within the atomic ensemble. On the other hand, the exchange of virtual photons within the ensemble leads to a tiny energy shift of the resonance line, the collective Lamb shift, that remained experimentally elusive for a long time after its prediction. Here we illustrate how highly brilliant synchrotron radiation allows one to prepare superradiant states of excited Mössbauer nuclei, an important condition for observation of the collective Lamb shift.

  7. Observation of the Phononic Lamb Shift with a Synthetic Vacuum

    Directory of Open Access Journals (Sweden)

    T. Rentrop

    2016-11-01

    Full Text Available In contrast to classical empty space, the quantum vacuum fundamentally alters the properties of embedded particles. This paradigm shift allows one to explain the discovery of the celebrated Lamb shift in the spectrum of the hydrogen atom. Here, we engineer a synthetic vacuum, building on the unique properties of ultracold atomic gas mixtures, offering the ability to switch between empty space and quantum vacuum. Using high-precision spectroscopy, we observe the phononic Lamb shift, an intriguing many-body effect originally conjectured in the context of solid-state physics. We find good agreement with theoretical predictions based on the Fröhlich model. Our observations establish this experimental platform as a new tool for precision benchmarking of open theoretical challenges, especially in the regime of strong coupling between the particles and the quantum vacuum.

  8. Flow Regime Classification and Hydrological Characterization: A Case Study of Ethiopian Rivers

    Directory of Open Access Journals (Sweden)

    Belete Berhanu

    2015-06-01

    Full Text Available The spatiotemporal variability of a stream flow due to the complex interaction of catchment attributes and rainfall induce complexity in hydrology. Researchers have been trying to address this complexity with a number of approaches; river flow regime is one of them. The flow regime can be quantified by means of hydrological indices characterizing five components: magnitude, frequency, duration, timing, and rate of change of flow. Similarly, this study aimed to understand the flow variability of Ethiopian Rivers using the observed daily flow data from 208 gauging stations in the country. With this process, the Hierarchical Ward Clustering method was implemented to group the streams into three flow regimes (1 ephemeral, (2 intermittent, and (3 perennial. Principal component analysis (PCA is also applied as the second multivariate analysis tool to identify dominant hydrological indices that cause the variability in the streams. The mean flow per unit catchment area (QmAR and Base flow index (BFI show an incremental trend with ephemeral, intermittent and perennial streams. Whereas the number of mean zero flow days ratio (ZFI and coefficient of variation (CV show a decreasing trend with ephemeral to perennial flow regimes. Finally, the streams in the three flow regimes were characterized with the mean and standard deviation of the hydrological variables and the shape, slope, and scale of the flow duration curve. Results of this study are the basis for further understanding of the ecohydrological processes of the river basins in Ethiopia.

  9. De Facto Regimes in International Law

    Directory of Open Access Journals (Sweden)

    Jonte van Essen

    2012-02-01

    Full Text Available The ambiguous position of de facto regimes in international law has long been the subject of scholarly debate and a source of political conflict. An assessment of the current standing of these regimes in international law and the consequences of actions by international actors on this status has, however, been long overdue. The manner in which de facto regimes are regarded internationally has serious consequences for the individuals under the influence of this legal grey area. Therefore, the study into this problem and possible solutions is of great significance. The 2011 developments in Northern Africa underline the need of contemporary research into this area. This essay aims to clarify the position of de facto regimes in international law and the influence on their status by actions of international actors. The author first argues that de facto regimes have rights and obligations under international law, which provide them with (some form of international legal personality. He then pleads for a reconsideration of the contemporary legal treatment of these regimes. The author argues against the current system of government recognition and proposes a system that better addresses the needs of both de facto regimes and the international community. 

  10. Evaluating the traditional day and night shift in an acute care surgery fellowship: Is the swing shift a better choice?

    Science.gov (United States)

    Chestovich, Paul J; McNicoll, Christopher F; Ingalls, Nichole K; Kuhls, Deborah A; Fraser, Douglas R; Morrissey, Shawna L; Fildes, John J

    2018-01-01

    Fellowship trainees in acute care surgery require experience in the management of complex and operative trauma cases. Trauma center staffing usually follows standard 12-hour or 24-hour shifts, with resident and fellow trainees following a similar schedule. Although trauma admissions can be generally unpredictable, we analyzed temporal trends of trauma patient arrival times to determine the best time frame to maximize trainee experience during each day. We reviewed 10 years (2007-2016) of trauma registry data for blunt and penetrating trauma activations. Hourly volumetric trends were observed, and three specific events were chosen for detailed analysis: (1) trauma activation with Injury Severity Score (ISS) greater than 15, (2) laparotomy for trauma, and (3) thoracotomy for trauma. A retrospective shift log was created, which included day (7:00 AM to 7:00 PM), night (7:00 PM to 7:00 AM), and swing (noon to midnight) shifts. A swing shift was chosen because it captures the peak volume for all three events. Means and 95% confidence intervals were calculated, and comparisons were made between shifts using the Wilcoxon matched-pairs signed rank test with Bonferroni correction, and p less than 0.05 considered significant. During the 10-year study period, 28,287 patients were treated at our trauma center. This included the evaluation and management of 7,874 patients with ISS greater than 15, performance of 1,766 laparotomies, and 392 thoracotomies for trauma. Swing shift was superior to both day and night shifts for ISS greater than 15 (p night shifts were superior to day shift for laparotomies (p day shift (p night shift (p = 0.031). Shifts with the highest yield of ISS greater than 15, laparotomies, and thoracotomies include night and swing shifts on Fridays and Saturdays. Projected experience of acute care surgery fellows in managing complex trauma patients increases with the integration of swing shifts into the schedule. Daily trauma volume follows a temporal pattern

  11. Is there a shift to 'active nanostructures'?

    International Nuclear Information System (INIS)

    Subramanian, Vrishali; Youtie, Jan; Porter, Alan L.; Shapira, Philip

    2010-01-01

    It has been suggested that an important transition in the long-run trajectory of nanotechnology development is a shift from passive to active nanostructures. Such a shift could present different or increased societal impacts and require new approaches for risk assessment. An active nanostructure 'changes or evolves its state during its operation,' according to the National Science Foundation's (2006) Active Nanostructures and Nanosystems grant solicitation. Active nanostructure examples include nanoelectromechanical systems (NEMS), nanomachines, self-healing materials, targeted drugs and chemicals, energy storage devices, and sensors. This article considers two questions: (a) Is there a 'shift' to active nanostructures? (b) How can we characterize the prototypical areas into which active nanostructures may emerge? We build upon the NSF definition of active nanostructures to develop a research publication search strategy, with a particular intent to distinguish between passive and active nanotechnologies. We perform bibliometric analyses and describe the main publication trends from 1995 to 2008. We then describe the prototypes of research that emerge based on reading the abstracts and review papers encountered in our search. Preliminary results suggest that there is a sharp rise in active nanostructures publications in 2006, and this rise is maintained in 2007 and through to early 2008. We present a typology that can be used to describe the kind of active nanostructures that may be commercialized and regulated in the future.

  12. Is there a shift to "active nanostructures"?

    Science.gov (United States)

    Subramanian, Vrishali; Youtie, Jan; Porter, Alan L.; Shapira, Philip

    2010-01-01

    It has been suggested that an important transition in the long-run trajectory of nanotechnology development is a shift from passive to active nanostructures. Such a shift could present different or increased societal impacts and require new approaches for risk assessment. An active nanostructure "changes or evolves its state during its operation," according to the National Science Foundation's (2006) Active Nanostructures and Nanosystems grant solicitation. Active nanostructure examples include nanoelectromechanical systems (NEMS), nanomachines, self-healing materials, targeted drugs and chemicals, energy storage devices, and sensors. This article considers two questions: (a) Is there a "shift" to active nanostructures? (b) How can we characterize the prototypical areas into which active nanostructures may emerge? We build upon the NSF definition of active nanostructures to develop a research publication search strategy, with a particular intent to distinguish between passive and active nanotechnologies. We perform bibliometric analyses and describe the main publication trends from 1995 to 2008. We then describe the prototypes of research that emerge based on reading the abstracts and review papers encountered in our search. Preliminary results suggest that there is a sharp rise in active nanostructures publications in 2006, and this rise is maintained in 2007 and through to early 2008. We present a typology that can be used to describe the kind of active nanostructures that may be commercialized and regulated in the future.

  13. TIPS (trigger an IIF paradigm shift)

    Energy Technology Data Exchange (ETDEWEB)

    Kilcup, P.E. Glen [Intel Corporation, MS: F9-016, 4100 Sara Road, Rio Rancho, NM 87124 (United States)]. E-mail: glen.w.kilcup@intel.com; Hickox, Dick [Intel Corporation, MS: F9-016, 4100 Sara Road, Rio Rancho, NM 87124 (United States); Reynaga, Adolfo [Intel Corporation, MS: F9-016, 4100 Sara Road, Rio Rancho, NM 87124 (United States)

    2007-04-11

    Challenge: New Mexico Corporate Services (NMCS) recordable injuries have been averaging 2-4 per year for the last 5 years with no statistical improvement. However, we believe all NM employees must go home incident and injury free every day and just as healthy as they came to work. In addition, we have received feedback from several sources, that indicates some employees are reluctant to report injuries. These indicators showed us that continuing our current strategies, making incremental improvement and changes, would not give us the improvement desired. We needed a paradigm shift to get everyone completely engaged in the IIF (Incident and Injury Free) culture, in order to achieve true IIF results. Methods/Strategies: We formed a small (3-person) taskforce consisting of safety representatives from EHS, Site Services and CS Operations. We reviewed 5 years worth of data to determine what was injuring our people. We also decided to review all injuries, not simply those classified as recordable by OSHA standards. First we identified the types of injury information needed to get a true picture of our safety issues. We analyzed IRB (Incident Review Board) data showing us the following factors and whether any of them contributed to the injury: - Date - Incident Description - Severity - Root Cause - Type of Injury - Season - Work Group/Shift - Area - Improper evaluation of hazard - Inadequate work procedures - Incorrect Mental Model - Inadequate PPE Requirement - Failure to Follow or Unaware of PPE Requirement - Shortcut or Schedule Pressure - Last or First Day of Shift or Adjacent to Holiday - OT - Aggravate Existing Condition - Inadequate Training or Passdown - Experience in Task - Corrective Action Taken - Overall Quality of Response. Once this information was collected for all injuries in an Excel file, we graphed it several ways to help reveal trends: - Shift 7 had double the injuries of shift 5 - Night shift injuries were relatively high but lower than Shift 7 -Shift

  14. TIPS (trigger an IIF paradigm shift)

    International Nuclear Information System (INIS)

    Kilcup, P.E. Glen; Hickox, Dick; Reynaga, Adolfo

    2007-01-01

    Challenge: New Mexico Corporate Services (NMCS) recordable injuries have been averaging 2-4 per year for the last 5 years with no statistical improvement. However, we believe all NM employees must go home incident and injury free every day and just as healthy as they came to work. In addition, we have received feedback from several sources, that indicates some employees are reluctant to report injuries. These indicators showed us that continuing our current strategies, making incremental improvement and changes, would not give us the improvement desired. We needed a paradigm shift to get everyone completely engaged in the IIF (Incident and Injury Free) culture, in order to achieve true IIF results. Methods/Strategies: We formed a small (3-person) taskforce consisting of safety representatives from EHS, Site Services and CS Operations. We reviewed 5 years worth of data to determine what was injuring our people. We also decided to review all injuries, not simply those classified as recordable by OSHA standards. First we identified the types of injury information needed to get a true picture of our safety issues. We analyzed IRB (Incident Review Board) data showing us the following factors and whether any of them contributed to the injury: - Date - Incident Description - Severity - Root Cause - Type of Injury - Season - Work Group/Shift - Area - Improper evaluation of hazard - Inadequate work procedures - Incorrect Mental Model - Inadequate PPE Requirement - Failure to Follow or Unaware of PPE Requirement - Shortcut or Schedule Pressure - Last or First Day of Shift or Adjacent to Holiday - OT - Aggravate Existing Condition - Inadequate Training or Passdown - Experience in Task - Corrective Action Taken - Overall Quality of Response. Once this information was collected for all injuries in an Excel file, we graphed it several ways to help reveal trends: - Shift 7 had double the injuries of shift 5 - Night shift injuries were relatively high but lower than Shift 7 -Shift

  15. TIPS (trigger an IIF paradigm shift).

    Science.gov (United States)

    Kilcup P E, Glen; Hickox, Dick; Reynaga, Adolfo

    2007-04-11

    New Mexico Corporate Services (NMCS) recordable injuries have been averaging 2-4 per year for the last 5 years with no statistical improvement. However, we believe all NM employees must go home incident and injury free every day and just as healthy as they came to work. In addition, we have received feedback from several sources, that indicates some employees are reluctant to report injuries. These indicators showed us that continuing our current strategies, making incremental improvement and changes, would not give us the improvement desired. We needed a paradigm shift to get everyone completely engaged in the IIF (Incident & Injury Free) culture, in order to achieve true IIF results. We formed a small (3-person) taskforce consisting of safety representatives from EHS, Site Services and CS Operations. We reviewed 5 years worth of data to determine what was injuring our people. We also decided to review all injuries, not simply those classified as recordable by OSHA standards. First we identified the types of injury information needed to get a true picture of our safety issues. We analyzed IRB (Incident Review Board) data showing us the following factors and whether any of them contributed to the injury: - Date - Incident Description - Severity - Root Cause - Type of Injury - Season - Work Group/Shift - Area - Improper evaluation of hazard - Inadequate work procedures - Incorrect Mental Model - Inadequate PPE Requirement - Failure to Follow or Unaware of PPE Requirement - Shortcut or Schedule Pressure - Last or First Day of Shift or Adjacent to Holiday - OT - Aggravate Existing Condition - Inadequate Training or Passdown - Experience in Task - Corrective Action Taken - Overall Quality of Response. Once this information was collected for all injuries in an Excel file, we graphed it several ways to help reveal trends: Shift 7 had double the injuries of shift 5. Night shift injuries were relatively high but lower than Shift 7. Shift 5 had no severe (recordable

  16. Chemical shift imaging: a review

    International Nuclear Information System (INIS)

    Brateman, L.

    1986-01-01

    Chemical shift is the phenomenon that is seen when an isotope possessing a nuclear magnetic dipole moment resonates at a spectrum of resonance frequencies in a given magnetic field. These resonance frequencies, or chemical shifts, depend on the chemical environments of particular nuclei. Mapping the spatial distribution of nuclei associated with a particular chemical shift (e.g., hydrogen nuclei associated with water molecules or with lipid groups) is called chemical shift imaging. Several techniques of proton chemical shift imaging that have been applied in vivo are presented, and their clinical findings are reported and summarized. Acquiring high-resolution spectra for large numbers of volume elements in two or three dimensions may be prohibitive because of time constraints, but other methods of imaging lipid of water distributions (i.e., selective excitation, selective saturation, or variations in conventional magnetic resonance imaging pulse sequences) can provide chemical shift information. These techniques require less time, but they lack spectral information. Since fat deposition seen by chemical shift imaging may not be demonstrated by conventional magnetic resonance imaging, certain applications of chemical shift imaging, such as in the determination of fatty liver disease, have greater diagnostic utility than conventional magnetic resonance imaging. Furthermore, edge artifacts caused by chemical shift effects can be eliminated by certain selective methods of data acquisition employed in chemical shift imaging

  17. Size-Dependent Shifts of Plasmon Resonance in Silver Nanoparticle Films Using Controlled Dissolution

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Kneipp, Katrin

    2014-01-01

    to a transition from an extrinsic regime for the larger particles, where shifts of the plasmon frequency are related to changes in the dielectric environment, while the dielectric function of the metal is constant, to an intrinsic regime for the smaller particles. For this intrinsic regime, operative for small...... in a corrected electron density. The reported results have potential for developing nanosensors based on small nanoparticles below 5 nm in size by using their intrinsic response to adsorbed analytes. This detection scheme suggests a potential increase in the sensitivity of up to 3×, particularly when redox...

  18. Anxiety about starting three-shift work among female workers: findings from the Female Shift Workers' Health Study.

    Science.gov (United States)

    Kubo, Tatsuhiko; Maruyama, Takashi; Shirane, Kiyoyumi; Otomo, Hajime; Matsumoto, Tetsuro; Oyama, Ichiro

    2008-03-01

    In 1999, the Japanese Law on Equal Employment Opportunity and Conditions was amended and the previous prohibition of the assignment of female workers to night work was abolished. Subsequently, the number of female shift workers has been increasing in Japan, necessitating greater attention to the health care of this population. The aim of the current study is to evaluate the relationship between anxiety expressed about starting three-shift work and background characteristics among female workers who were being assigned to three-shift work for the first time. The subjects were 38 middle-aged female workers (age range: 44 to 59 years) who were working at a chemical plant. The women completed a self-administered questionnaire before starting three-shift work. Levels of anxiety about starting three-shift work were assessed by the question 'Do you feel anxious about starting three-shift work?' The available responses were: 'Very agree', 'Considerably agree', 'Rather agree', 'Slightly agree' and 'Not agree at all', and 63% of the subjects gave one of the first two answers, which were defined as indicating anxiety. We also acquired information regarding lifestyle and occupation for each subject, including the following factors: frequency of breakfast consumption, subjective sleep insufficiency, previous experience of similar work before beginning shift work, previous experience of two-shift work, and responsibility for household duties. In the study, we found a marginally statistically significant trend association between frequent breakfast consumption and anxiety about starting three-shift work (P(trend) = 0.09). Anxiety was also high among subjects with sleep disorders, especially those suffering from subjective sleep insufficiency (P = 0.08). Due to the small study population, these results should be interpreted with caution and confirmed by future studies.

  19. A meta-level analysis of major trends in environmental health risk governance

    NARCIS (Netherlands)

    Runhaar, H.A.C.; Driessen, P.P.J.; Bree, L. van; Sluijs, J.P. van der

    2010-01-01

    Internationally but also within countries, large differences exist regarding how environmental health risks (EHRs) are governed. Despite these differences, at a meta-level some general trends can be discerned that may point to a convergence of EHR governance regimes. One, EHR governance regimes are

  20. Feasibility of a dual regime gyrotron

    International Nuclear Information System (INIS)

    Sawant, Ashwini; Jain, Prerit; Kartikeyan, M.V.

    2012-01-01

    The design concept of a 42/84 GHz, 500 kW, CW, dual-regime gyrotron for ECRH of plasma in an experimental Tokamak will be presented in this paper. Operation at 42 GHz is fundamental where as that in 84 GHz will be second harmonic so that a similar guidance system will be retained for dual regime operation. In this paper, the mode competition and mode selection procedures are presented for such a dual regime operation. Cold cavity design and self-consistent calculations will be carried out for power and efficiencies. (author)

  1. Can Old Regimes Handle New Wars?

    DEFF Research Database (Denmark)

    Henningsen, Troels

    Research on New Wars argues that since the 1980s states and regimes have become more vulnerable to violence from non-state actors. Two developments in the Sahel region support the New Wars thesis: an increase in Islamist radicalization and new access to the global black market, both of which......, the paper finds that regimes in the Sahel region are still able to cope with the rise in non-state threats. The paper first shortly compares the longevity of the present regimes in the Sahel region to all previous ones, second examines in-depth how Chad and Mali fight the insurgents. Findings are that since...

  2. Framing of regimes and transition strategies

    DEFF Research Database (Denmark)

    Jensen, Jens Stissing

    2012-01-01

    This article suggests that transition strategies are always formulated in the context of specific representations of the regime and the challenges it faces. It is argued that the framing of a regime affects the envisioning of transition strategies. An analysis of the current development agenda...... for the housing construction sector in Denmark reveals the relevance and impacts of different regime framings. It is proposed that the ability to cope with framing issues as situated and political processes is at the core of the governance of transitions....

  3. FEL in transverse optical klystron regime

    International Nuclear Information System (INIS)

    Scarlat, F.; Baltateanu, N.

    1994-01-01

    Among all operational regimes of free electron laser (FEL), the transverse optical regime (TOK) requires the least stringent electron beam parameters. The device associated to this regime, also defined as FEL with two or more components, consists of two or more identical interaction sections separated by one or more drift distances among themselves. Starting from the motion equations which describe the interaction between an electron and the radiation inside the undulator, one can obtain some practical expressions for the calculation of the efficiency of the energy transfer from the electron to the radiation, and the gain of the external coherent radiation for a FEL in TOK with three cavities. (Author)

  4. Two regimes of the Arctic's circulation from ocean models with ice and contaminants.

    Science.gov (United States)

    Proshutinsky, A Y; Johnson, M

    2001-01-01

    A two-dimensional barotropic, coupled, ocean-ice model with a space resolution of 55.5 km and driven by atmospheric forces, river run-off, and sea-level slope between the Pacific and the Arctic Oceans, has been used to simulate the vertically averaged currents and ice drift in the Arctic Ocean. Results from 43 years of numerical simulations of water and ice motions demonstrate that two wind-driven circulation regimes are possible in the Arctic, a cyclonic and an anti-cyclonic circulation. These two regimes appear to alternate at 5-7 year intervals with the 10-15 year period. It is important to pollution studies to understand which circulation regime prevails at any time. It is anticipated that 1995 is a year with a cyclonic regime, and during this cyclonic phase and possibly during past cyclonic regimes as well, pollutants may reach the Alaskan shelf. The regime shifts demonstrated in this paper are fundamentally important to understanding the Arctic's general circulation and particularly important for estimating pollution transport.

  5. Chemical shift homology in proteins

    International Nuclear Information System (INIS)

    Potts, Barbara C.M.; Chazin, Walter J.

    1998-01-01

    The degree of chemical shift similarity for homologous proteins has been determined from a chemical shift database of over 50 proteins representing a variety of families and folds, and spanning a wide range of sequence homologies. After sequence alignment, the similarity of the secondary chemical shifts of C α protons was examined as a function of amino acid sequence identity for 37 pairs of structurally homologous proteins. A correlation between sequence identity and secondary chemical shift rmsd was observed. Important insights are provided by examining the sequence identity of homologous proteins versus percentage of secondary chemical shifts that fall within 0.1 and 0.3 ppm thresholds. These results begin to establish practical guidelines for the extent of chemical shift similarity to expect among structurally homologous proteins

  6. Shifted-modified Chebyshev filters

    OpenAIRE

    ŞENGÜL, Metin

    2013-01-01

    This paper introduces a new type of filter approximation method that utilizes shifted-modified Chebyshev filters. Construction of the new filters involves the use of shifted-modified Chebyshev polynomials that are formed using the roots of conventional Chebyshev polynomials. The study also includes 2 tables containing the shifted-modified Chebyshev polynomials and the normalized element values for the low-pass prototype filters up to degree 6. The transducer power gain, group dela...

  7. Portable shift register

    International Nuclear Information System (INIS)

    Halbig, J.K.; Bourret, S.C.; Hansen, W.J.; Hicks, D.V.; Klosterbuer, S.F.; Krick, M.S.

    1994-01-01

    An electronics package for a small, battery-operated, self-contained, neutron coincidence counter based on a portable shift-register (PSR) has been developed. The counter was developed for applications not adequately addressed by commercial packages, including in-plant measurements to demonstrate compliance with regulations (domestic and international), in-plant process control, and in-field measurements (environmental monitoring or safeguards). Our package's features, which address these applications, include the following: Small size for portability and ease of installation;battery or mains operation; a built-in battery to power the unit and a typical detector such as a small sample counter, for over 6 h if power lines are bad or noisy, if there is a temporary absence of power, or if portability is desired; complete support, including bias, for standard neutron detectors; a powerful communications package to easily facilitate robust external control over a serial port; and a C-library to simplify creating external control programs in computers or other controllers. Whereas the PSR specifically addresses the applications mentioned above, it also performs all the measurements made by previous electronics packages for neutron coincidence counters developed at Los Alamos and commercialized. The PSR electronics package, exclusive of carrying handle, is 8 by 10 by 20 cm; it contains the circuit boards, battery, and bias supply and weighs less than 2 kg. This instrument package is the second in an emerging family of portable measurement instruments being developed; the first was the Miniature and Modular Multichannel Analyzer (M 3 CA). The PSR makes extensive use of hardware and software developed for the M 3 CA; like the M 3 CA, it is intended primarily for use with an external controller interfaced over a serial channel

  8. Transition from linear- to nonlinear-focusing regime in filamentation

    Science.gov (United States)

    Lim, Khan; Durand, Magali; Baudelet, Matthieu; Richardson, Martin

    2014-01-01

    Laser filamentation in gases is often carried out in the laboratory with focusing optics to better stabilize the filament, whereas real-world applications of filaments frequently involve collimated or near-collimated beams. It is well documented that geometrical focusing can alter the properties of laser filaments and, consequently, a transition between a collimated and a strongly focused filament is expected. Nevertheless, this transition point has not been identified. Here, we propose an analytical method to determine the transition, and show that it corresponds to an actual shift in the balance of physical mechanisms governing filamentation. In high-NA conditions, filamentation is primarily governed by geometrical focusing and plasma effects, while the Kerr nonlinearity plays a more significant role as NA decreases. We find the transition between the two regimes to be relatively insensitive to the intrinsic laser parameters, and our analysis agrees well with a wide range of parameters found in published literature. PMID:25434678

  9. The international climate regime: towards consolidation collapse

    International Nuclear Information System (INIS)

    Berthaud, P.; Cavard, D.; Criqui, P.

    2003-10-01

    This article deals with the different modalities that exist to manage a problem of collective action in the field of climate negotiation. It uses two concepts of the International Political Economy (IPE): the concept of International Regime (IR) and the concept of Hegemony and / or Leadership. The course the international negotiation has taken between 1992 (Rio Convention) and march 2001 (the US rejection of the Kyoto Protocol of 1997) leads us, first, to question the conditions of existence as well as the viability of a non-hegemonic International Regime (Part One). Then, we discuss the perspectives for the 'post - Kyoto' era. After having examined the preferences of the three most active actors in the negotiation (USA, Europe, G77 + China) combined with the leadership capacities they possess, we identify three scenarios for the future: i) anarchy, ii) an international regime under the American hegemony, iii) an international regime under the European leadership (Part Two). (author)

  10. The CTBT regime, significance and potential benefits

    International Nuclear Information System (INIS)

    Chang, Hong-Lae

    2002-01-01

    This presentation briefly outlines the CTBT's background, describes the activities of the Preparatory Commission, the verification regime, the role of the National Data Centres and international coopereation. The objectives of the Nairobi workshop are listed

  11. Improving the taxation regime for electric power

    International Nuclear Information System (INIS)

    Fjermeros, Morten; Ilstad, Kristine

    2003-01-01

    In Norway, the present taxation regime for electric power is very complex. The power companies are currently charged with ordinary tax on profits, tax on economic rent, tax on natural resources and land tax. In addition there are the rules about licence fees, yield of power due to concession conditions, and reversion. The Norwegian Electricity Industry Association (EBL), assisted by a firm of lawyers, has proposed an improvement over the current taxation regime

  12. Brazil in the global anticorruption regime

    Directory of Open Access Journals (Sweden)

    Marcos Tourinho

    2018-03-01

    Full Text Available Abstract Brazilian anticorruption law and institutions were significantly transformed in recent decades. This article traces those transformations and explains how the international anticorruption and money laundering regimes contributed to their development. It argues that those international regimes were internalised in the Brazilian system through three mechanisms: inspiration and legitimation, coercion, and implementation support, and were critical to the transformation of Brazilian institutions.

  13. Portfolio Selection with Jumps under Regime Switching

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2010-01-01

    Full Text Available We investigate a continuous-time version of the mean-variance portfolio selection model with jumps under regime switching. The portfolio selection is proposed and analyzed for a market consisting of one bank account and multiple stocks. The random regime switching is assumed to be independent of the underlying Brownian motion and jump processes. A Markov chain modulated diffusion formulation is employed to model the problem.

  14. Do discriminatory pay regimes unleash antisocial behavior?

    OpenAIRE

    Grosch, Kerstin; Rau, Holger A.

    2017-01-01

    In this paper, we analyze how pay-regime procedures affect antisocial behavior at the workplace. In a real-effort experiment we vary two determinants of pay regimes: discrimination and justification of payments by performance. In our Discrimination treatment half of the workforce is randomly selected and promoted and participate in a tournament (high-income workers) whereas the other half receives no payment (lowincome workers). Afterwards, antisocial behavior is measured by a Joy-of-Destruct...

  15. Anthropogenic Water Uses and River Flow Regime Alterations by Dams

    Science.gov (United States)

    Ferrazzi, M.; Botter, G.

    2017-12-01

    Dams and impoundments have been designed to reconcile the systematic conflict between patterns of anthropogenic water uses and the temporal variability of river flows. Over the past seven decades, population growth and economic development led to a marked increase in the number of these water infrastructures, so that unregulated free-flowing rivers are now rare in developed countries and alterations of the hydrologic cycle at global scale have to be properly considered and characterized. Therefore, improving our understanding of the influence of dams and reservoirs on hydrologic regimes is going to play a key role in water planning and management. In this study, a physically based analytic approach is combined to extensive hydrologic data to investigate natural flow regime alterations downstream of dams in the Central-Eastern United States. These representative case studies span a wide range of different uses, including flood control, water supply and hydropower production. Our analysis reveals that the most evident effects of flood control through dams is a decrease in the intra-seasonal variability of flows, whose extent is controlled by the ratio between the storage capacity for flood control and the average incoming streamflow. Conversely, reservoirs used for water supply lead to an increase of daily streamflow variability and an enhanced inter-catchment heterogeneity. Over the last decades, the supply of fresh water required to sustain human populations has become a major concern at global scale. Accordingly, the number of reservoirs devoted to water supply increased by 50% in the US. This pattern foreshadows a possible shift in the cumulative effect of dams on river flow regimes in terms of inter-catchment homogenization and intra-annual flow variability.

  16. Long-term demographic trends in a fire-suppressed mixed-conifer forest

    Science.gov (United States)

    Carrie R. Levine; Flora Krivak-Tetley; Natalie S. van Doorn; Jolie-Anne S. Ansley; John J. Battles

    2016-01-01

    In the western United States, forests are experiencing novel environmental conditions related to a changing climate and a suppression of the historical fire regime. Mixed-conifer forests, considered resilient to disturbance due to their heterogeneity in structure and composition, appear to be shifting to a more homogeneous state, but the timescale of these shifts is...

  17. State Structure and Political Regime Structure

    Directory of Open Access Journals (Sweden)

    Paul – Iulian Nedelcu

    2012-05-01

    Full Text Available The political regime is the concrete form of organization and functioning of political system andtherefore, the regime means the concrete way of organize, institutionalize and function a political systemand of the exercise of political power by a social-political force in a social community or global socialistem. The political regime is not limited to institutions and state bodies, but it covers the entire politicalsystem. Form of expression in social practice plan is the result of balance of forces between classes ofcitizens, organizations, between them and civil society and politics.Designates the concrete form ofgovernment formation and organization, of state bodies, in aspect of their characteristics and principles, therelations between them and other state bodies, and also as the relationship between them and otherinstitutionalized forms of political systems. Instead, the political regime is an explicit realization ofaxiological operations, a specific hierarchy of values, in general and political values, in particular. Even ifsome elements of the political regime overlap to some extent and in some respects, those of form orstructure of guvernamnt state, thus they dissolve his identity, distinct quality of being specific traits of thepolitical regime.

  18. Stochastic Parametrisations and Regime Behaviour of Atmospheric Models

    Science.gov (United States)

    Arnold, Hannah; Moroz, Irene; Palmer, Tim

    2013-04-01

    The presence of regimes is a characteristic of non-linear, chaotic systems (Lorenz, 2006). In the atmosphere, regimes emerge as familiar circulation patterns such as the El-Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO) and Scandinavian Blocking events. In recent years there has been much interest in the problem of identifying and studying atmospheric regimes (Solomon et al, 2007). In particular, how do these regimes respond to an external forcing such as anthropogenic greenhouse gas emissions? The importance of regimes in observed trends over the past 50-100 years indicates that in order to predict anthropogenic climate change, our climate models must be able to represent accurately natural circulation regimes, their statistics and variability. It is well established that representing model uncertainty as well as initial condition uncertainty is important for reliable weather forecasts (Palmer, 2001). In particular, stochastic parametrisation schemes have been shown to improve the skill of weather forecast models (e.g. Berner et al., 2009; Frenkel et al., 2012; Palmer et al., 2009). It is possible that including stochastic physics as a representation of model uncertainty could also be beneficial in climate modelling, enabling the simulator to explore larger regions of the climate attractor including other flow regimes. An alternative representation of model uncertainty is a perturbed parameter scheme, whereby physical parameters in subgrid parametrisation schemes are perturbed about their optimal value. Perturbing parameters gives a greater control over the ensemble than multi-model or multiparametrisation ensembles, and has been used as a representation of model uncertainty in climate prediction (Stainforth et al., 2005; Rougier et al., 2009). We investigate the effect of including representations of model uncertainty on the regime behaviour of a simulator. A simple chaotic model of the atmosphere, the Lorenz '96 system, is used to study

  19. Work shifts in Emergency Medicine

    Directory of Open Access Journals (Sweden)

    Roberto Recupero

    2007-06-01

    Full Text Available Emergency Medicine is known as a high stress specialty. The adverse effect of constantly rotating shifts is the single most important reason given for premature attrition from the field. In this work problems tied with night shift work will be taken into account and some solutions to reduce the impact of night work on the emergency physicians will be proposed.

  20. Flexible Schedules and Shift Work.

    Science.gov (United States)

    Beers, Thomas M.

    2000-01-01

    Flexible work hours have gained prominence, as more than 25 million workers (27.6% of all full-time workers) can now vary their schedules. However, there has been little change since the mid-1980s in the proportion who work a shift other than a regular daytime shift. (JOW)

  1. Migrating Seals on Shifting Sands: Testing Alternate Hypotheses for Holocene Ecological and Cultural Change on the California Coast

    Science.gov (United States)

    Koch, P. L.; Newsome, S. D.; Gifford-Gonzalez, D.

    2001-12-01

    The coast of California presented Holocene humans with a diverse set of ecosystems and geomorphic features, from large islands off a semi-desert mainland in the south, to a mix of sandy and rocky beaches abutting grassland and oak forest in central California, to a rocky coast hugged by dense coniferous forest in the north. Theories explaining trends in human resource use, settlement patterns, and demography are equally diverse, but can be categorized as 1) driven by diffusion of technological innovations from outside the region, 2) driven by population growth leading to more intensive extraction of resources, or 3) driven by climatic factors that affect the resource base. With respect to climatic shifts, attention has focused on a possible regime shift ca. 5500 BP, following peak Holocene warming, and on evidence for massive droughts and a drop in marine productivity ca. 1000 BP. While evidence for a coincidence between climatic, cultural, and ecological change is present, albeit complex, in southern California, similar data are largely lacking from central and northern California. We are using isotopic and archaeofaunal analysis to test ideas for ecological and cultural change in central California. Three features of the archaeological record are relevant. First, overall use of marine resources by coastal communities declined after 1000 BP. Second, northern fur seals, which are common in earlier sites, drop in abundance relative to remaining marine animals. We have previously established that Holocene humans in central California were hunting gregariously-breeding northern fur seals from mainland rookeries. These seals breed exclusively on offshore islands today, typically at high latitudes. Their restriction to these isolated sites today may be a response to human overexploitation of their mainland rookeries prehistorically. Finally, collection of oxygen and carbon isotope data from mussels at the archaeological sites, while still in a preliminary phase, has

  2. Spectral transformations in the regime of pulse self-trapping in a nonlinear photonic crystal

    International Nuclear Information System (INIS)

    Novitsky, Denis V.

    2011-01-01

    We consider the interaction of a femtosecond light pulse with a one-dimensional photonic crystal with relaxing cubic nonlinearity in the regime of self-trapping. By use of numerical simulations, it is shown that, under certain conditions, the spectra of reflected and transmitted light possess the properties of narrowband (quasimonochromatic) or wideband (continuumlike) radiation. It is remarkable that these spectral features appear due to a significant frequency shift and occur inside a photonic band gap of the structure under investigation.

  3. Multiple growth regimes: Insights from unified growth theory

    OpenAIRE

    Galor, Oded

    2007-01-01

    Unified Growth Theory uncovers the forces that contributed to the existence of multiple growth regimes and the emergence of convergence clubs. It suggests that differential timing of take-offs from stagnation to growth segmented economies into three fundamental regimes: slow growing economies in a Malthusian regime, fast growing countries in a sustained growth regime, and economies in the transition between these regimes. In contrast to existing research that links regime switching thresholds...

  4. Flow and heat transfer in laminar–turbulent transitional flow regime under rolling motion

    International Nuclear Information System (INIS)

    Yuan, Hongsheng; Tan, Sichao; Zhuang, Nailiang; Lan, Shu

    2016-01-01

    Highlights: • Flow and heat transfer experiment in transitional flow regime under rolling motion. • Increases of average friction factor and Nu were found. • Periodic breakdown of laminar flow contributes to the increase. • Nonlinear variation of pressure drop or Nu with Re also contributes to the increase. • Effect of critical Reynolds number shift was discussed. - Abstract: Flow and heat transfer characteristics under rolling motion are extremely important to thermohydraulic analysis of offshore nuclear reactors. An experimental study was conducted in a heated rectangular channel to investigate flow and heat transfer in laminar–turbulent transitional flow regime under rolling motion. The results showed that the average friction factor and Nusselt number are higher than that of the corresponding steady flow as the flow rate fluctuates in transitional flow regime. Larger relative flow rate fluctuation was observed under larger rolling amplitude or higher rolling frequency. In the same manner, larger increases of average friction factor and Nusselt number were achieved under larger rolling amplitude or higher rolling frequency. The increases were mainly caused by the flow rate fluctuation through periodic breakdown of laminar flow and development of turbulence in laminar–turbulent transitional flow regime. First, turbulence, which enhances the rate of momentum and energy exchange, occurs near the crest of flow rate wave even the flow is still in laminar flow regime according to the average Reynolds number. Second, as a result of rapid increases of the friction and heat transfer with Reynolds number in transitional flow regime, the increases of the friction and the heat transfer near the crest of flow rate wave are larger than the decreases of them near the trough of flow rate wave, which also contributes to increases of average friction and heat transfer. Additionally, the effect of critical Reynolds number shift under unsteady flow and heating

  5. Causas estruturais e consequências dos regimes internacionais: regimes como variáveis intervenientes

    OpenAIRE

    Krasner, Stephen D.

    2012-01-01

    Os regimes internacionais são definidos como princípios, normas, regras e procedimentos de tomada de decisões ao redor dos quais as expectativas dos atores convergem em uma dada área-tema. Como ponto de partida, os regimes são conceituados como variáveis intervenientes, estando entre fatores causais básicos e os resultados e comportamentos relacionados. Há três visões a respeito da importância dos regimes: as orientações estruturais convencionais desvalorizam os regimes como sendo, na melhor ...

  6. Precipitation regime classification for the Mojave Desert: Implications for fire occurrence

    Science.gov (United States)

    Tagestad, Jerry; Brooks, Matthew L.; Cullinan, Valerie; Downs, Janelle; McKinley, Randy

    2016-01-01

    Long periods of drought or above-average precipitation affect Mojave Desert vegetation condition, biomass and susceptibility to fire. Changes in the seasonality of precipitation alter the likelihood of lightning, a key ignition source for fires. The objectives of this study were to characterize the relationship between recent, historic, and future precipitation patterns and fire. Classifying monthly precipitation data from 1971 to 2010 reveals four precipitation regimes: low winter/low summer, moderate winter/moderate summer, high winter/low summer and high winter/high summer. Two regimes with summer monsoonal precipitation covered only 40% of the Mojave Desert ecoregion but contain 88% of the area burned and 95% of the repeat burn area. Classifying historic precipitation for early-century (wet) and mid-century (drought) periods reveals distinct shifts in regime boundaries. Early-century results are similar to current, while the mid-century results show a sizeable reduction in area of regimes with a strong monsoonal component. Such a shift would suggest that fires during the mid-century period would be minimal and anecdotal records confirm this. Predicted precipitation patterns from downscaled global climate models indicate numerous epochs of high winter precipitation, inferring higher fire potential for many multi-decade periods during the next century.

  7. Trends in Education.

    Science.gov (United States)

    School Planning & Management, 2002

    2002-01-01

    Several architects, planners, administrators, and contractors answer questions about trends related to school construction, interior design, business, security, and technology. Trends concern funding issues, specialized designs, planning for safety, technological integration, and equity in services. (EV)

  8. Marketing Trends to Watch

    Science.gov (United States)

    Circle, Alison

    2009-01-01

    This article identifies 13 cultural trends that libraries can turn into opportunites to reach patrons. These trends include: Twitter, online reputation management, value added content, mobile marketing, and emotional connection.

  9. Lung Cancer Trends

    Science.gov (United States)

    ... the Biggest Cancer Killer in Both Men and Women” Stay Informed Trends for Other Kinds of Cancer Breast Cervical Colorectal (Colon) Ovarian Prostate Skin Cancer Home Lung Cancer Trends Language: English Español (Spanish) Recommend ...

  10. The performance of exchange rate regimes in three SADC countries: An overview

    Directory of Open Access Journals (Sweden)

    Bernard N. Iyke

    2014-08-01

    Full Text Available This paper provides an overview of the real exchange rate and economic growth dynamics in three low-income Southern African countries, namely: the Democratic Republic of Congo (DRC, Malawi and Mozambique. Specifically, the paper investigates the nature of exchange rate regimes and the impact that they have on economic growth, as well as the movement of real exchange rates and real GDP from 1970—2010 in these countries. The paper identifies the following trends: Fixed exchange regimes were pursued from the 1960s until the late 1980s and early 1990s in these countries, which were growth-repressing; the countries pursued floating and managed-floating regimes from the 1990s to date, resulting in moderate-to-rapid economic growth. We conclude that liberalised exchange rates, which lead to undervalued currencies in these Southern African countries, were growth-enhancing.

  11. Censoring the Press: A Barometer of Government Tolerance for Anti-regime Dissent under Authoritarian Rule

    Directory of Open Access Journals (Sweden)

    Elizabeth Ann Stein

    2016-01-01

    Full Text Available This paper proposes that dissident leaders aiming to build mass opposition movements follow the mainstream press to help them gauge government tolerance for anti-government mass actions in repressive authoritarian regimes. Under conditions of censorship, media–state interactions serve as a barometer of the government’s disposition toward and capacity to impede public displays of dissent. Observing trends in coverage and the government’s reaction to this coverage helps activist leaders assess when it should be safest to plan anti-government mass actions, such as demonstrations, marches, or strikes. Using original data derived from coding content from the Brazilian newspaper Folha de São Paulo over the period of 1974–1982, I test whether opposition mass actions followed trends in taboo content and government treatment of the press during the period of political liberalization of Brazil’s military regime.

  12. Transformative Shifts in Art History Teaching: The Impact of Standards-Based Assessment

    Science.gov (United States)

    Ormond, Barbara

    2011-01-01

    This article examines pedagogical shifts in art history teaching that have developed as a response to the implementation of a standards-based assessment regime. The specific characteristics of art history standards-based assessment in the context of New Zealand secondary schools are explained to demonstrate how an exacting form of assessment has…

  13. Career Planning Trends in Japanese Companies

    OpenAIRE

    Firkola, Peter

    2005-01-01

    This paper provides an overview of career planning trends in Japanese companies. Research on career development in Japan is first reviewed. Career planning practices in Japanese companies are examined. Factors influencing career planning choice are then discussed. It was found that there appears to be a change occurring in the career planning practices, specifically the shifting of responsibility for an employees' career from the employer to the employee. (JEL Classifi-cation: M12, M54

  14. New Trends in Mobile Technology Leadership

    Directory of Open Access Journals (Sweden)

    Silviu Cojocaru

    2014-05-01

    Full Text Available The mobile device market proved one of the most dynamic, with the leader in intelligent phones changing at least four times during the last decade. At least one important acquisition was registered during 2013 (when Microsoft bought Nokia’s mobile phone division and this event is slated to induce major shifts within the structure of this market. With this story we aim to provide information related to trends foreseen for this market.

  15. Progress towards a global nuclear liability regime

    International Nuclear Information System (INIS)

    2014-01-01

    During its April 2014 meeting, the Steering Committee for Nuclear Energy held a policy debate on 'Progress towards a Global Nuclear Liability Regime'. The Steering Committee heard presentations from several experts on nuclear liability issues. To prepare the delegates to the Steering Committee for the policy debate, the NEA Secretariat prepared a background note on the status of the nuclear liability regimes, as well as on current issues and challenges in implementing the regimes. This article is based on the background note and is intended to provide basic information on the relevant international conventions and an overview of recent developments to enhance the understanding of the legal framework in which policy-makers and practitioners are engaging to respond to the call for broader adherence to the international liability instruments. (authors)

  16. Determination of the Hall Thruster Operating Regimes

    International Nuclear Information System (INIS)

    L. Dorf; V. Semenov; Y. Raitses; N.J. Fisch

    2002-04-01

    A quasi one-dimensional (1-D) steady-state model of the Hall thruster is presented. For the same discharge voltage two operating regimes are possible -- with and without the anode sheath. For given mass flow rate, magnetic field profile and discharge voltage a unique solution can be constructed, assuming that the thruster operates in one of the regimes. However, we show that for a given temperature profile the applied discharge voltage uniquely determines the operating regime: for discharge voltages greater than a certain value, the sheath disappears. That result is obtained over a wide range of incoming neutral velocities, channel lengths and widths, and cathode plane locations. It is also shown that a good correlation between the quasi 1-D model and experimental results can be achieved by selecting an appropriate electron mobility and temperature profile

  17. Causas estruturais e consequências dos regimes internacionais: regimes como variáveis intervenientes

    Directory of Open Access Journals (Sweden)

    Stephen D. Krasner

    2012-06-01

    Full Text Available Os regimes internacionais são definidos como princípios, normas, regras e procedimentos de tomada de decisões ao redor dos quais as expectativas dos atores convergem em uma dada área-tema. Como ponto de partida, os regimes são conceituados como variáveis intervenientes, estando entre fatores causais básicos e os resultados e comportamentos relacionados. Há três visões a respeito da importância dos regimes: as orientações estruturais convencionais desvalorizam os regimes como sendo, na melhor das hipóteses, ineficazes; as orientações grocianas vêem os regimes como componentes íntimos do sistema internacional; as perspectivas estruturalistas modificadas vêem os regimes como significativos somente em certas condições restritas. Para os argumentos grociano e estruturalista modificado - que concordam com a visão de que os regimes podem influenciar resultados e comportamentos - , o desenvolvimento de regimes é visto como uma função de cinco variáveis causais básicas: auto-interesse egoísta; poder político; normas e princípios difusos; usos e costumes; conhecimento.

  18. Coulomb drag in the mesoscopic regime

    DEFF Research Database (Denmark)

    Mortensen, N. Asger; Flensberg, Karsten; Jauho, Antti-Pekka

    2002-01-01

    We present a theory for Coulomb drug between two mesoscopic systems which expresses the drag in terms of scattering matrices and wave functions. The formalism can be applied to both ballistic and disordered systems and the consequences can be studied either by numerical simulations or analytic...... means such as perturbation theory or random matrix theory. The physics of Coulomb drag in the mesoscopic regime is very different from Coulomb drag between extended electron systems. In the mesoscopic regime we in general find fluctuations of the drag comparable to the mean value. Examples are vanishing...

  19. Coulomb drag in the mesoscopic regime

    DEFF Research Database (Denmark)

    Mortensen, N.A.; Flensberg, Karsten; Jauho, Antti-Pekka

    2002-01-01

    We present a theory for Coulomb drag between two mesoscopic systems which expresses the drag in terms of scattering matrices and wave functions. The formalism can be applied to both ballistic and disordered systems and the consequences can be studied either by numerical simulations or analytic...... means such as perturbation theory or random matrix theory. The physics of Coulomb drag in the mesoscopic regime is very different from Coulomb drag between extended electron systems. In the mesoscopic regime we in general find fluctuations of the drag comparable to the mean value. Examples are vanishing...

  20. WELFARE REGIMES IN LATIN AMERICA AND CARIBBEAN

    Directory of Open Access Journals (Sweden)

    Melisa Campana-Alabarce

    2015-06-01

    Full Text Available This article provides a characterization of Latin American and Caribbean Welfare regimes in historiographical perspective. Firstly, it makes a review of the emergence conditions of Welfare States in Western Europe and its core features, with particular emphasis on its role as a method to regulate inequalities in industrial capitalism. Dialoguing with it, then stops in the specific configurations that welfare regimes have taken in Latin America during the course of the twentieth century. Finally, it provides a map of its contemporary features and the major challenges that the States of the region face in his capacity as right guarantors for the future.

  1. The oil tax regime of Azerbaijan

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Gerard

    1998-07-01

    Azerbaijan has a long history in the oil business and a chance of a spectacular future. To understand why the oil tax regime evolved into its present form and how it is likely to develop, it is necessary to know something of the country's history and the commercial environment. Consequently the presentation begins by discussing these items. It then outlines the Production Sharing Agreement regime in Azerbaijan and then deals with the Kazakh and Georgian Tax Codes, as these are likely to be the basis of a new general tax law in Azerbaijan from 1999. The presentation includes comments on the New Draft Tax Code of 1998.

  2. The oil tax regime of Azerbaijan

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Gerard

    1998-07-01

    Azerbaijan has a long history in the oil business and a chance of a spectacular future. To understand why the oil tax regime evolved into its present form and how it is likely to develop, it is necessary to know something of the country's history and the commercial environment. Consequently the presentation begins by discussing these items. It then outlines the Production Sharing Agreement regime in Azerbaijan and then deals with the Kazakh and Georgian Tax Codes, as these are likely to be the basis of a new general tax law in Azerbaijan from 1999. The presentation includes comments on the New Draft Tax Code of 1998.

  3. Regimes of flow past a vortex generator

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Okulov, V.L.; Naumov, I.V.

    2012-01-01

    A complete parametric investigation of the development of multi-vortex regimes in a wake past simple vortex generator has been carried out. It is established that the vortex structure in the wake is much more complicated than a simple monopole tip vortex. The vortices were studied by stereoscopic...... particle image velocimetry (SPIV). Based on the obtained SPIV data, a map of the regimes of flow past the vortex generator has been constructed. One region with a developed stable multivortex system on this map reaches the vicinity of the optimum angle of attack of the vortex generator....

  4. Flocking regimes in a simple lattice model.

    Science.gov (United States)

    Raymond, J R; Evans, M R

    2006-03-01

    We study a one-dimensional lattice flocking model incorporating all three of the flocking criteria proposed by Reynolds [Computer Graphics 21, 4 (1987)]: alignment, centering, and separation. The model generalizes that introduced by O. J. O'Loan and M. R. Evans [J. Phys. A. 32, L99 (1999)]. We motivate the dynamical rules by microscopic sampling considerations. The model exhibits various flocking regimes: the alternating flock, the homogeneous flock, and dipole structures. We investigate these regimes numerically and within a continuum mean-field theory.

  5. Legal Regimes of Official Information in Ukraine

    Directory of Open Access Journals (Sweden)

    Serhii Yesimov

    2018-04-01

    Full Text Available In the article on the basis of the methodology of system analysis the legal nature and sources of legal regulation of the legal regime of official information in Ukraine in the conditions of adaptation of Ukrainian legislation to the legislation of the European Union are considered. A comparative legal analysis of official information in the public-law and private-law spheres in the context of legal regimes of restricted information, confidential information and information classified as state secrets has been conducted.

  6. Human impacts on river ice regime in the Carpathian Basin

    Science.gov (United States)

    Takács, Katalin; Nagy, Balázs; Kern, Zoltán

    2014-05-01

    examples from the Carpathian Basin represent some of the most common human impacts (engineering regulation, hydropower usage, water pollution), disturbing natural river ice regimes of mid-latitude rivers with densely populated or dynamically growing urban areas along their courses. In addition simple tests are also introduced to detect not only the climatic, but also the effect of anthropogenic impacts on river ice regime. As a result of river regulation on River Danube at Budapest a vanishing trend in river ice phenomena could be detected in the Danube records. The average ice-affected season shortened from 40 to 27 days, the average ice-covered season reduced greatly, from 27 to 7 days. In historical times the ice jams on the River Danube caused many times ice floods. The relative frequency of the break-up jam also decreased; moreover no ice flood occurred over the past 50 years. The changes due to hydropower usage are different upstream and downstream to the damming along the river. On Raba River upstream of the Nick dam at Ragyogóhíd, the ice-affected and ice-covered seasons were lengthened by 4 and 9 days, in contrast, downstream of the dam, the length of the ice-covered season was shortened by 7 days, and the number of ice-affected days decreased by 8 days at Árpás. During the observation period at Budapest on Danube River, the temperature requirements for river ice phenomena occurrence changed. Nowadays, much lower temperatures are needed to create the same ice phenomena compared to the start of the observations. For ice appearance, the mean winter air temperature requirements decreased from +2.39 °C to +1.71 °C. This investigation focused on anthropogenic effects on river ice regime, eliminating the impact of climatic conditions. Different forms of anthropogenic effects cause in most cases, a shorter length of ice-affected seasons and decreasing frequency of ice phenomena occurrence. Rising winter temperatures result the same changes in river ice regime

  7. Inequalities for scattering phase shifts

    International Nuclear Information System (INIS)

    Baumgartner, B.; Grosse, H.

    1985-01-01

    A recently developed method, which was used to derive bounds on energy levels, is applied to continuous spectra and gives relations between scattering phase shifts of various angular momenta. (Author)

  8. Isotope shifts in unstable nuclei

    International Nuclear Information System (INIS)

    Rebel, H.

    1980-05-01

    Current experimental investigations of isotope shifts in atomic spectra of unstable nuclei and the resulting information about size and shape of nuclei far off stability are discussed with reference to some representative examples. (orig.)

  9. The Catholic church and politics in Colombia: a shifting foundation

    OpenAIRE

    Estrem, David J.

    2016-01-01

    Approved for public release; distribution is unlimited Recent research reveals a precipitous decrease in Catholic adherents across Latin America. Since 1970, numerous Latin Americans have professed a shift to Protestantism. Scholars have analyzed this trend within certain countries and as a regional tendency, but have not comprehensively addressed the Colombian case. Colombia is often considered the most Catholic of Latin American countries, with the Church historically much enmeshed in na...

  10. Clinical investigation of set-shifting subtypes in anorexia nervosa.

    Science.gov (United States)

    Abbate-Daga, Giovanni; Buzzichelli, Sara; Marzola, Enrica; Amianto, Federico; Fassino, Secondo

    2014-11-30

    While evidence continues to accumulate on the relevance of cognitive inflexibility in anorexia nervosa (AN), its clinical correlates remain unclear. We aimed at examining the relationship between set-shifting and clinical variables (i.e., eating psychopathology, depression, and personality) in AN. Ninety-four individuals affected by AN and 59 healthy controls (HC) were recruited. All participants were assessed using: Eating Disorders Inventory-2 (EDI-2), Temperament and Character Inventory (TCI), Beck Depression Inventory (BDI), and Wisconsin Card Sorting Test (WCST). The AN group scored worse than HCs on set-shifting. According to their neuropsychological performances, AN patients were split into two groups corresponding to poor (N=30) and intact (N=64) set-shifting subtypes. Interoceptive awareness, impulse regulation, and maturity fears on the EDI-2 and depression on the BDI differed across all groups (HC, intact, and poor set-shifting subtype). Self-directedness on the TCI differed significantly among all groups. Cooperativeness and reward dependence differed instead only between HC and AN poor set-shifting subtype. After controlling for depression, only interoceptive awareness remained significant with reward dependence showing a trend towards statistical significance. These findings suggest that multiple clinical variables may be correlated with set-shifting performances in AN. The factors contributing to impaired cognitive inflexibility could be more complex than heretofore generally considered. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Statistics of exchange rate regimes in Nigeria | Iwueze | Global ...

    African Journals Online (AJOL)

    The three distinct exchange rate regimes of Nigeria were subjected to Autoregressive Integrated Moving Average (ARIMA) modeling in order to compare them with respect to model structure. It was found that the three regimes admit different models. Regime one admits Moving average model of order 2, Regime two admits ...

  12. How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes.

    Directory of Open Access Journals (Sweden)

    Lluís Brotons

    Full Text Available Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain. We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape

  13. How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes.

    Science.gov (United States)

    Brotons, Lluís; Aquilué, Núria; de Cáceres, Miquel; Fortin, Marie-Josée; Fall, Andrew

    2013-01-01

    Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and

  14. How Fire History, Fire Suppression Practices and Climate Change Affect Wildfire Regimes in Mediterranean Landscapes

    Science.gov (United States)

    Brotons, Lluís; Aquilué, Núria; de Cáceres, Miquel; Fortin, Marie-Josée; Fall, Andrew

    2013-01-01

    Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and

  15. Technological regimes and sources of entrepreneurship

    NARCIS (Netherlands)

    Marsili, O.

    2002-01-01

    This paper concerns the technological determinants of entrepreneurial behaviour. By applying a typology of technological regimes, which describes the nature of the technological environment in which firms operate, this paper examines the sources and obstacles to entrepreneurial entry related to the

  16. Searching for an Appropriate Exchange Rate Regime

    Directory of Open Access Journals (Sweden)

    Yunjong Wang

    2001-06-01

    Full Text Available This paper attempts to survey current debates on the choice of exchange rate regime in emerging market economies. The issue of choosing an appropriate exchange rate regime is being actively discussed since the recent Asian crisis. As a lesson from the recent crises, one widely shared conclusion is that soft peg exchange rate regimes are extremely vulnerable in a world of volatile capital movements. Consequently, new orthodoxy based on the impossible trinity hypothesis favours two corner solutions ― greater flexibility or credible institutional assurance, like a currency board system or dollarization. Nevertheless, questions whether such corner solutions are adequate for developing countries are rising of late. "Fear of floating" is still conspicuous in many developing countries having adopted nominally a free-floating exchange rate regime. Developing countries are sensitive to exchange rate fluctuations because the cost of exchange rate volatility is greater than the benefit when compared to developed countries. Monitoring bands is a compromise solution, but it still needs further enhancement of estimation techniques for fundamental equilibrium exchange rates in order to make those estimation results more workable in practice. Other alternatives include the creation of soft peg of the G-3 currencies. Despite counterarguments, the stability of G-3 currencies could prove to be beneficial to emerging market economies.

  17. Negotiating a regime to control global warming

    International Nuclear Information System (INIS)

    Sebenius, J.K.

    1991-01-01

    For purposes of analysis, this paper has uncritically maintained that the prospect of a serious climate problem exists and has only lightly examined the broader advantages and drawbacks of various proposed policy and institutional responses. Crucial as they are to a full treatment of the issues, these underlying substantive and policy questions enter the analysis primarily insofar as they affect the likely outcomes of pending and potential negotiations. To an advocate of a new greenhouse control regime, the fundamental negotiating task is to craft and sustain a meaningful winning coalition of countries backing such a regime. Two centrally necessary conditions for the fundamental task are: (1) that each member of the coalition see enough gain in the regime relative to the alternatives to adhere and (2) the potential and actual blocking coalitions of interests opposed to the regime be prevented from forming and from being acceptably accommodated or otherwise neutralized. The analysis of this paper is organized around key questions whose answers will influence whether and how these two necessary conditions might (or might not) be met

  18. Yukon's common oil and gas regime

    International Nuclear Information System (INIS)

    Love, B.

    1998-01-01

    The Yukon's common oil and gas regime was developed in partnership with First Nations and it sets out the rules that will apply throughout the Yukon and on Yukon and First Nation lands. While separate and distinct, it conforms with and is compatible with other government systems and regimes. The major elements of the common regime include the Oil and Gas Act, regulations, policies, processes and agreements. The specific opportunities that are available in each phase of oil and gas development in the Yukon are described, with a map showing all basins, reserves and sites of current oil and gas activity. The Yukon has eight potential oil and gas basins: North Coast, Old Crow, Kandik, Eagle Plain, Peel Plateau, Bonnet Plume, Whitehorse Trough, and Liard Plateau. Only three of the eight, the Liard Plateau, Whitehorse Trough and Eagle Plain, have been explored. No wells have been drilled in several of Yukon's basins. Factors influencing economic opportunities in the Territory are also described, including: (1) international events and energy markets, (2) North American gas markets, (3) environmental factors, (4) competitiveness of the Yukon regime, and (5) the commitment of industry resources. 4 figs

  19. Technological regimes and sources of entrepreneurship

    NARCIS (Netherlands)

    Marsili, O.

    2000-01-01

    This paper concerns the technological detenninants of entrepreneurial behaviour. By applying a typology of technological regimes, which describes the nature of the technological environment in which finns operate, this paper examines the sources and obstacle to entrepreneurial entry related to the

  20. Comprehensive review of the maritime safety regimes.

    NARCIS (Netherlands)

    S. Knapp (Sabine); Ph.H.B.F. Franses (Philip Hans)

    2007-01-01

    textabstractThis report presents a comprehensive review of the maritime safety regimes and provides recommendations on how to improve the system. The results show a complex legal framework which generates a high amount of inspections and overlapping of inspection areas where no cross-recognition is

  1. Plugging regime in the pump limiter throat

    International Nuclear Information System (INIS)

    Ghendrih, P.; Grosman, A.; Samain, A.; Capes, H.; Morera, J.P.

    1988-08-01

    The plugging regime -with no outstreaming neutral flux- is studied for a closed configuration pump limiter (throat). We derive the plugging length and the neutral density build-up at the neutralizer plate. The analytical expressions are supported by numerical evidence. We find an improved efficiency related to the throat effect mainly due to neutral-sidewall interactions

  2. European welfare regimes: Political orientations versus poverty

    Directory of Open Access Journals (Sweden)

    Josifidis Kosta

    2011-01-01

    Full Text Available This inquiry analyzes how political orientations shape welfare states and labour market institutions when seeking to reduce poverty. In order to identify effects of these two key variables, we conduct a panel regression analysis that includes two poverty measures: poverty rates before and after social spending. This inquiry considers 14 EU countries, and in the period from 1995 to 2008, which are grouped according to welfare state regimes. We consider Social Democratic, Corporatist, Mediterranean and Liberal welfare state regimes. Panel regression results indicate that political orientation engenders no significant statistically measurable effects on poverty rates before social spending. Effects register, however, as significant when considering poverty rates after social spending. With respect to the first set of results, we advance two key explanations. First, we note a longer period of time is necessary in order to observe actual effects of political orientation on market generated poverty. Second, political parties with their respective programs do not register as influential enough to solve social problems related to income distribution when taken alone. Influences register as indirect and are expressed through changes in employment rates and social spending. The second set of results support the hypothesis that a selected political regime does indeed contribute to poverty reduction. In sum, political orientation and political regime does indeed affect poverty through welfare state institutions, as well as through labour market institutions.

  3. Radiative effects of global MODIS cloud regimes

    Science.gov (United States)

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji

    2018-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations. PMID:29619289

  4. Radiative Effects of Global MODIS Cloud Regimes

    Science.gov (United States)

    Oraiopoulos, Lazaros; Cho, Nayeong; Lee, Dong Min; Kato, Seiji

    2016-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations.

  5. The Forex Regime and EMU Expansion

    NARCIS (Netherlands)

    P.W. van Foreest; C.G. de Vries (Casper)

    2002-01-01

    textabstractThis paper provides empirical evidence that, irrespective of the foreign exchange rate regime, countries with high monetary volatility have lower relative output growth rates. It is argued that due to the forward looking nature of the foreign exchange market, exchange rate stability

  6. Trust in regulatory regimes: scoping the field

    NARCIS (Netherlands)

    Six, F.E.; Verhoest, Koen

    2017-01-01

    This edited volume is the first endeavour to systematically investigate the role of trust in the different relations within regulatory regimes. Trust as a multifaceted concept is contested within public administration and political science in general and especially within the relation between

  7. A Comparative Typology of Pension Regimes

    NARCIS (Netherlands)

    Arjan Soede; Cok Vrooman

    2008-01-01

    This report presents an empirical typology of pension regimes in the European Union, the US, Canada, Australia and Norway. The categorisation is based on 34 quantitative and qualitative characteristics of the mandatory parts of the pension systems in these countries. The empirical analysis shows

  8. An emissions trading regime for Canada

    International Nuclear Information System (INIS)

    Smith, S.L.

    2001-01-01

    In 1998, over twelve papers were published on emissions trading regimes in Canada by the National Round Table on the Environment and the Economy (NRTEE), a federal government agency whose members represent stakeholders as varied as business, environmental groups, academics, aboriginal groups and others. One of the recommendations that emerged was for the computer modelling of the possibilities that had been identified for a domestic trading regime in Canada for greenhouse gases. It is unclear whether the modelling was ever performed as the file was taken over by the Finance Department under the umbrella of a special emission trading table that examined Canada's commitment under the Kyoto Protocol. The author examined questions pertaining to whether a domestic trading regime is essential, and what its characteristics should be in case it was deemed essential or advisable to have one. The upstream versus downstream application was looked at, as well as grand-fathering versus auction. Provincial issues were then addressed, followed by meshing with a credit system. International systems were reviewed. Early action was discussed, whereby an emitter seeks credit for action taken toward reductions since the original reference year of 1990. The case of emitters having bought or sold permits since the original reference years will also want those trades recognized under a trading regime. The author indicated that it seems probable that an emission trading system will eventually be implemented and that a debate on the issue should be initiated early

  9. EUROPEAN INFLUENCE ON ETHIOPIAN ANTITRUST REGIME:

    African Journals Online (AJOL)

    eliasn

    Introduction. Despite a noticeable European influence on the Ethiopian competition legal regime, some aspects of Ethiopia's 2003 Trade Practice Proclamation are still inadequate to appropriately deal with certain competition problems. The limitations of the rules need to be put right since achievement of the very goals of ...

  10. [The "specific" liability regime for blood products].

    Science.gov (United States)

    Byk, Christian

    2017-10-13

    Based on the system of liability for defective products as organized by the European Directive of 25 July 1985, responsibility for blood products does not therefore constitute a genuine specific regime. However, European law leaves States a margin of discretion in the implementation of the Directive with regard to health products. This is the case in particular with the exemption for development risk.

  11. Altered stream-flow regimes and invasive plant species: The Tamarix case

    Science.gov (United States)

    Stromberg, J.C.; Lite, S.J.; Marler, R.; Paradzick, C.; Shafroth, P.B.; Shorrock, D.; White, J.M.; White, M.S.

    2007-01-01

    Aim: To test the hypothesis that anthropogenic alteration of stream-flow regimes is a key driver of compositional shifts from native to introduced riparian plant species. Location: The arid south-western United States; 24 river reaches in the Gila and Lower Colorado drainage basins of Arizona. Methods: We compared the abundance of three dominant woody riparian taxa (native Populus fremontii and Salix gooddingii, and introduced Tamarix) between river reaches that varied in stream-flow permanence (perennial vs. intermittent), presence or absence of an upstream flow-regulating dam, and presence or absence of municipal effluent as a stream water source. Results: Populus and Salix were the dominant pioneer trees along the reaches with perennial flow and a natural flood regime. In contrast, Tamarix had high abundance (patch area and basal area) along reaches with intermittent stream flows (caused by natural and cultural factors), as well as those with dam-regulated flows. Main conclusions: Stream-flow regimes are strong determinants of riparian vegetation structure, and hydrological alterations can drive dominance shifts to introduced species that have an adaptive suite of traits. Deep alluvial groundwater on intermittent rivers favours the deep-rooted, stress-adapted Tamarix over the shallower-rooted and more competitive Populus and Salix. On flow-regulated rivers, shifts in flood timing favour the reproductively opportunistic Tamarix over Populus and Salix, both of which have narrow germination windows. The prevailing hydrological conditions thus favour a new dominant pioneer species in the riparian corridors of the American Southwest. These results reaffirm the importance of reinstating stream-flow regimes (inclusive of groundwater flows) for re-establishing the native pioneer trees as the dominant forest type. ?? 2007 The Authors Journal compilation ?? 2007 Blackwell Publishing Ltd.

  12. Dispersal limitation drives successional pathways in Central Siberian forests under current and intensified fire regimes.

    Science.gov (United States)

    Tautenhahn, Susanne; Lichstein, Jeremy W; Jung, Martin; Kattge, Jens; Bohlman, Stephanie A; Heilmeier, Hermann; Prokushkin, Anatoly; Kahl, Anja; Wirth, Christian

    2016-06-01

    Fire is a primary driver of boreal forest dynamics. Intensifying fire regimes due to climate change may cause a shift in boreal forest composition toward reduced dominance of conifers and greater abundance of deciduous hardwoods, with potential biogeochemical and biophysical feedbacks to regional and global climate. This shift has already been observed in some North American boreal forests and has been attributed to changes in site conditions. However, it is unknown if the mechanisms controlling fire-induced changes in deciduous hardwood cover are similar among different boreal forests, which differ in the ecological traits of the dominant tree species. To better understand the consequences of intensifying fire regimes in boreal forests, we studied postfire regeneration in five burns in the Central Siberian dark taiga, a vast but poorly studied boreal region. We combined field measurements, dendrochronological analysis, and seed-source maps derived from high-resolution satellite images to quantify the importance of site conditions (e.g., organic layer depth) vs. seed availability in shaping postfire regeneration. We show that dispersal limitation of evergreen conifers was the main factor determining postfire regeneration composition and density. Site conditions had significant but weaker effects. We used information on postfire regeneration to develop a classification scheme for successional pathways, representing the dominance of deciduous hardwoods vs. evergreen conifers at different successional stages. We estimated the spatial distribution of different successional pathways under alternative fire regime scenarios. Under intensified fire regimes, dispersal limitation of evergreen conifers is predicted to become more severe, primarily due to reduced abundance of surviving seed sources within burned areas. Increased dispersal limitation of evergreen conifers, in turn, is predicted to increase the prevalence of successional pathways dominated by deciduous hardwoods

  13. On the Nature of Trends

    DEFF Research Database (Denmark)

    Mackinney-Valentin, Maria

    2010-01-01

    A consolidation of the field Trend Studies through mapping, updating and developing trend theory.......A consolidation of the field Trend Studies through mapping, updating and developing trend theory....

  14. Energy Trends 2012; Energie Trends 2012

    Energy Technology Data Exchange (ETDEWEB)

    Van Dril, T. (ed.); Gerdes, J. (ed.) [ECN Beleidsstudies, Petten (Netherlands); Marbus, S. (ed.) [Energie-Nederland, Den Haag (Netherlands); Boelhouwer, M. (ed.) [Netbeheer Nederland, Arnhem (Netherlands)

    2012-11-15

    In Energy Trends 2012, all figures and developments in the field of energy in the Netherlands are presented in conjunction. The book provides information on energy use by consumers and businesses, provides insight into the international energy trade, energy production and development of energy networks [Dutch] In Energie Trends 2012 staan alle cijfers en ontwikkelingen op het gebied van energie in Nederland in samenhang gepresenteerd. Het boek biedt informatie over energiegebruik door consumenten en bedrijven, geeft inzage in de internationale energiehandel en energieproductie en biedt inzicht in de ontwikkeling van de energienetten.

  15. The global safety regime - Setting the stage

    International Nuclear Information System (INIS)

    Meserve, R.A.

    2005-01-01

    The existing global safety regime has arisen from the exercise of sovereign authority, with an overlay of voluntary international cooperation from a network of international and regional organizations and intergovernmental agreements. This system has, in the main, served us well. For several reasons, the time is ripe to consider the desired shape of a future global safety regime and to take steps to achieve it. First, every nation's reliance on nuclear power is hostage to some extent to safety performance elsewhere in the world because of the effects on public attitudes and hence there is an interest in ensuring achievement of common standards. Second, the world is increasingly interdependent and the vendors of nuclear power plants seek to market their products throughout the globe. Efficiency would arise from the avoidance of needless differences in approach that require custom modifications from country to country. Finally, we have much to learn from each other and a common effort would strengthen us all. Such an effort might also serve to enhance public confidence. Some possible characteristics of such a regime can be identified. The regime should reflect a global consensus on the level of safety that should be achieved. There should be sufficient standardization of approach so that expertise and equipment can be used everywhere without significant modification. There should be efforts to ensure a fundamental commitment to safety and the encouragement of a safety culture. And there should be efforts to adopt more widely the best regulatory practices, recognizing that some modifications in approach may be necessary to reflect each nation's legal and social culture. At the same type, the regime should have the characteristics of flexibility, transparency, stability, practicality, and encouragement of competence. (author)

  16. Dune growth under multidirectional wind regimes

    Science.gov (United States)

    Gadal, C.; Rozier, O.; Claudin, P.; Courrech Du Pont, S.; Narteau, C.

    2017-12-01

    Under unidirectional wind regimes, flat sand beds become unstable to produce periodic linear dunes, commonly called transverse dunes because their main ridges are oriented perpendicular to the air flow. In areas of low sediment availability, the same interactions between flow, transport and topography produce barchan dunes, isolated sand-pile migrating over long distances with a characteristic crescentic shape. For the last fifteen years, barchan dunes and the instability at the origin of transverse dunes have been the subject of numerous studies that have identified a set of characteristic length and time scales with respect to the physical properties of both grains and fluid. This is not the case for dunes developing under multidirectional wind regimes. Under these conditions, dune orientation is measured with respect to the direction of the resultant sand flux. Depending on the wind regime, dunes do not always line up perpendicularly to the resultant sand flux, but can also be at an oblique angle or even parallel to it. These oblique and longitudinal dunes are ubiquitous in all deserts on Earth and planetary bodies because of the seasonal variability of wind orientation. They are however poorly constrained by observations and there is still no complete theoretical framework providing a description of their orientation and initial wavelength. Here, we extend the linear stability analysis of a flat sand of bed done in two dimensions for a unidirectional flow to three dimensions and multidirectional flow regimes. We are able to recover transitions from transverse to oblique or longitudinal dune patterns according to changes in wind regimes. We besides give a prediction for the initial dune wavelength. Our results compare well to previous theory of dune orientation and to field, experimental and numerical data.

  17. Shifting schedules: the health effects of reorganizing shift work.

    Science.gov (United States)

    Bambra, Clare L; Whitehead, Margaret M; Sowden, Amanda J; Akers, Joanne; Petticrew, Mark P

    2008-05-01

    Approximately one fifth of workers are engaged in some kind of shift work. The harmful effects of shift work on the health and work-life balance of employees are well known. A range of organizational interventions has been suggested to address these negative effects. This study undertook the systematic review (following Quality Of Reporting Of Meta [QUORUM] analyses guidelines) of experimental and quasi-experimental studies, from any country (in any language) that evaluated the effects on health and work-life balance of organizational-level interventions that redesign shift work schedules. Twenty-seven electronic databases (medical, social science, economic) were searched. Data extraction and quality appraisal were carried out by two independent reviewers. Narrative synthesis was performed. The review was conducted between October 2005 and November 2006. Twenty-six studies were found relating to a variety of organizational interventions. No one type of intervention was found to be consistently harmful to workers. However, three types were found to have beneficial effects on health and work-life balance: (1) switching from slow to fast rotation, (2) changing from backward to forward rotation, and (3) self-scheduling of shifts. Improvements were usually at little or no direct organizational cost. However, there were concerns about the generalizability of the evidence, and no studies reported on impacts on health inequalities. This review reinforces the findings of epidemiologic and laboratory-based research by suggesting that certain organizational-level interventions can improve the health of shift workers, their work-life balance, or both. This evidence could be useful when designing interventions to improve the experience of shift work.

  18. Computer architecture technology trends

    CERN Document Server

    1991-01-01

    Please note this is a Short Discount publication. This year's edition of Computer Architecture Technology Trends analyses the trends which are taking place in the architecture of computing systems today. Due to the sheer number of different applications to which computers are being applied, there seems no end to the different adoptions which proliferate. There are, however, some underlying trends which appear. Decision makers should be aware of these trends when specifying architectures, particularly for future applications. This report is fully revised and updated and provides insight in

  19. SAT in shift manager training

    International Nuclear Information System (INIS)

    Lecuyer, F.

    1995-01-01

    EDF has improved the organization of the operation shift teams with the replacement of shift supervisor in shift manager function. The shift manager is not only responsible for tasks associated to plant operation (production), but he is also responsible for safety of these tasks and for management of shift team members. A job analysis of this new job position has been performed in order to design the training programme. It resulted in a 10-month training programme that includes 8 weeks in safety-related topics and 12 weeks in soft-skills related topics. The safety related training courses are mandatory, the other courses are optional courses depending on individual trainee needs. The training also includes the development of management competencies. During the 10 month period, each trainee develops an individual project that is evaluated by NPP manager. As well, as group project is undertaken by the trainees and overseen by a steering committee. The steering committee participates in the evaluation process and provides operational experience feedback to the trainee groups and to the overall programme

  20. Adiabatic perturbation theory for atoms and molecules in the low-frequency regime.

    Science.gov (United States)

    Martiskainen, Hanna; Moiseyev, Nimrod

    2017-12-14

    There is an increasing interest in the photoinduced dynamics in the low frequency, ω, regime. The multiphoton absorptions by molecules in strong laser fields depend on the polarization of the laser and on the molecular structure. The unique properties of the interaction of atoms and molecules with lasers in the low-frequency regime imply new concepts and directions in strong-field light-matter interactions. Here we represent a perturbational approach for the calculations of the quasi-energy spectrum in the low-frequency regime, which avoids the construction of the Floquet operator with extremely large number of Floquet channels. The zero-order Hamiltonian in our perturbational approach is the adiabatic Hamiltonian where the atoms/molecules are exposed to a dc electric field rather than to ac-field. This is in the spirit of the first step in the Corkum three-step model. The second-order perturbation correction terms are obtained when iℏω∂∂τ serves as a perturbation and τ is a dimensionless variable. The second-order adiabatic perturbation scheme is found to be an excellent approach for calculating the ac-field Floquet solutions in our test case studies of a simple one-dimensional time-periodic model Hamiltonian. It is straightforward to implement the perturbation approach presented here for calculating atomic and molecular energy shifts (positions) due to the interaction with low-frequency ac-fields using high-level electronic structure methods. This is enabled since standard quantum chemistry packages allow the calculations of atomic and molecular energy shifts due to the interaction with dc-fields. In addition to the shift of the energy positions, the energy widths (inverse lifetimes) can be obtained at the same level of theory. These energy shifts are functions of the laser parameters (low frequency, intensity, and polarization).

  1. Does the ARFIMA really shift?

    DEFF Research Database (Denmark)

    Monache, Davide Delle; Grassi, Stefano; Santucci de Magistris, Paolo

    Short memory models contaminated by level shifts have long-memory features similar to those associated to processes generated under fractional integration. In this paper, we propose a robust testing procedure, based on an encompassing parametric specification, that allows to disentangle the level...... the highest power compared to other existing tests for spurious long-memory. Finally, we illustrate the usefulness of the proposed approach on the daily series of bipower variation and share turnover and on the monthly inflation series of G7 countries....... shift term from the ARFIMA component. The estimation is carried out via a state-space methodology and it leads to a robust estimate of the fractional integration parameter also in presence of level shifts.The Monte Carlo simulations show that this approach produces unbiased estimates of the fractional...

  2. United theory of planet formation (i): Tandem regime

    Science.gov (United States)

    Ebisuzaki, Toshikazu; Imaeda, Yusuke

    2017-07-01

    to be volatile-free because of the high temperature (>1000 K) at this formation site. Such water-free rocky particles may explain the formation of enstatite chondrites, of which the Earth is likely to be primarily composed of. It is also consistent with the model in which the Earth was initially formed as a completely volatile-free planet. The water and other volatile elements came later through the accretion of icy particles by the occasional scatterings in the outer regions. Our new proposed tandem planet formation regime shows that planetesimals are formed at two distinct sites (outer and inner edges of the MRI suppressed region). The former is likely to be the source of outer gas giants and the latter inner rocky planets. The tandem regime also explains the gap in the distribution of solid components (2-4 AU), which is necessary to form a ;solar-system-like; planetary system, which has a relatively small Mars and a very small mass in the main asteroid belt. We found that this tandem regime dose not take place when the vertical magnetic field of the disk five times weaker compared with that we assumed in the present paper, since the outer MRI front shift outward beyond 100 AU. This suggests that yet other regimes exists in our united theory. It may explain the variation observed in exsoplanetary systems by variations in magnetic field and probably angular momentum of the parent molecular cloud.

  3. Paradigm Shifts in Ophthalmic Diagnostics.

    Science.gov (United States)

    Sebag, J; Sadun, Alfredo A; Pierce, Eric A

    2016-08-01

    Future advances in ophthalmology will see a paradigm shift in diagnostics from a focus on dysfunction and disease to better measures of psychophysical function and health. Practical methods to define genotypes will be increasingly important and non-invasive nanotechnologies are needed to detect molecular changes that predate histopathology. This is not a review nor meant to be comprehensive. Specific topics have been selected to illustrate the principles of important paradigm shifts that will influence the future of ophthalmic diagnostics. It is our impression that future evaluation of vision will go beyond visual acuity to assess ocular health in terms of psychophysical function. The definition of disease will incorporate genotype into what has historically been a phenotype-centric discipline. Non-invasive nanotechnologies will enable a paradigm shift from disease detection on a cellular level to a sub-cellular molecular level. Vision can be evaluated beyond visual acuity by measuring contrast sensitivity, color vision, and macular function, as these provide better insights into the impact of aging and disease. Distortions can be quantified and the psychophysical basis of vision can be better evaluated than in the past by designing tests that assess particular macular cell function(s). Advances in our understanding of the genetic basis of eye diseases will enable better characterization of ocular health and disease. Non-invasive nanotechnologies can assess molecular changes in the lens, vitreous, and macula that predate visible pathology. Oxygen metabolism and circulatory physiology are measurable indices of ocular health that can detect variations of physiology and early disease. This overview of paradigm shifts in ophthalmology suggests that the future will see significant improvements in ophthalmic diagnostics. The selected topics illustrate the principles of these paradigm shifts and should serve as a guide to further research and development. Indeed

  4. Unifying role of radial electric field shear in the confinement trends of transitionless regimes in TFTR

    International Nuclear Information System (INIS)

    Ernst, D.R.; Beer, M.; Batha, S.

    2001-01-01

    Turbulence suppression by radial electric field shear (E r ) is shown to be important in the enhanced confinement of TFTR supershot plasmas. Simulations of supershot ion temperature profiles are performed using an existing parameterization of transport due to toroidal ion temperature gradient modes, extended to include suppression by E r shear. New spectroscopic measurements of E r differ significantly from prior neoclassical estimates. Supershot temperature profiles appear to be consistent with a criterion describing near-complete turbulence suppression by intrinsically generated E r shear. Helium spoiling and xenon puffing experiments are simulated to illustrate the role of E r shear in the confinement changes observed. (author)

  5. Unifying role of radial electric field shear in the confinement trends of transitionless regimes in TFTR

    International Nuclear Information System (INIS)

    Ernst, D.R.; Beer, M.; Batha, S.

    1999-01-01

    Turbulence suppression by radial electric field shear (E r ) is shown to be important in the enhanced confinement of TFTR supershot plasmas. Simulations of supershot ion temperature profiles are performed using an existing parameterization of transport due to toroidal ion temperature gradient modes, extended to include suppression by E r shear. New spectroscopic measurements of E r differ significantly from prior neoclassical estimates. Supershot temperature profiles appear to be consistent with a criterion describing near-complete turbulence suppression by intrinsically generated E r shear. Helium spoiling and xenon puffing experiments are simulated to illustrate the role of E r shear in the confinement changes observed. (author)

  6. Renormalization of Molecular Quasiparticle Levels at Metal-Molecule Interfaces: Trends across Binding Regimes

    DEFF Research Database (Denmark)

    Thygesen, Kristian Sommer; Rubio, Angel

    2009-01-01

    a microscopic model of the metal-molecule interface, we illustrate the basic features of this renormalization mechanism through systematic GW, Hartree-Fock, and Kohn-Sham calculations for the molecular energy levels as function of the model parameters. We identify two different polarization mechanisms: (i...

  7. Morphisms Between Sofic Shift Spaces

    DEFF Research Database (Denmark)

    Nielsen, Jan Agentoft

    The lower entropy factor problem asks for necessary and sufficient conditions for the existence of a factor map from a (mixing) sofic shift space onto another (mixing) sofic subshift of lower entropy. The problem was posed by Mike Boyle in 1984. It remains an open problem, but the present thesis...... gives a re-formulation which can be used to effectively decide the question for a larger class of sofic shifts than all previous results. In addition, the methods are used to make progress on the corresponding embedding problem which asks for necessary and sufficient conditions for the existence...

  8. Shift-Variant Multidimensional Systems.

    Science.gov (United States)

    1985-05-29

    x,y;u,v) is the system response at (x,y) to an unit impulse applied at (u,v). The presence of additive noise in the preceding input-output model of a...space model developed works very effi- ciently to deblur images affected by 2-D linear shift- varying blurs, its use, in presence of noise needs to be...causal linear shift-variant (LSV) system, whose impulse res- ponse is a K-th order degenerate sequence, a K-th order state-space model was obtained

  9. Explaining (Missing) Regulator Paradigm Shifts

    DEFF Research Database (Denmark)

    Wigger, Angela; Buch-Hansen, Hubert

    2014-01-01

    The global financial and economic crisis has prompted some scholars to suggest that a fundamental regulatory shift away from neoliberalism will take place – both in general and in the field of EU competition regulation. This paper shows that so far no radical break with the neoliberal type...... regulation after the crisis in the 1970s, the paper argues that the preconditions for a fundamental shift in this issue area are not present this time around. Several reasons account for this: the current crisis has been construed by economic and political elites as a crisis within and not of neoliberal...

  10. Choice of exchange rate regimes for African countries: Fixed or Flexible Exchange rate regimes?

    OpenAIRE

    Simwaka, Kisu

    2010-01-01

    The choice of an appropriate exchange rate regime has been a subject of ongoing debate in international economics. The majority of African countries are small open economies and thus where the choice of the exchange rate regime is an important policy issue. Aside from factors such as interest rates and inflation, the exchange rate is one of the most important determinants of a country’s relative level of economic health. For this reason, exchange rates are among the most watched analyzed and ...

  11. Trend Monitoring and Forecasting

    Science.gov (United States)

    2015-03-11

    including breaking news, meme , and commemorative day, on the context patterns. Table 2 shows the example pattern of classifying context pattern feature...used the following rule to find the ‘ meme ’. If the trending topic contains ‘#’ AND ‘subject+verb’, then trending topic is ‘ Meme ’. Table 2 Context

  12. Water Grabbing and the Role of Power: Shifting Water Governance in the Light of Agricultural Foreign Direct Investment

    Directory of Open Access Journals (Sweden)

    Andrea Bues

    2012-06-01

    Full Text Available In recent years, the trend for foreign actors to secure land for agricultural production in low-income countries has increased substantially. The concurrent acquisition of water resources changes the institutional arrangement for water management in the investment areas. The consequences of 'land grabbing' on the local water governance systems have not so far been adequately examined. This paper presents an institutional analysis of a small-scale irrigation scheme in Ethiopia, where foreign and national horticultural farms started to use water from an irrigation canal that was formerly managed as a user-group common-pool resource by local smallholders. The study follows a qualitative case-study approach with semi-structured interviews as the main source of data. For the analysis we employed the Common-pool Resource Theory and the Distributional Theory of Institutional Change. We found that the former management regime changed in that most of the farmers’ water rights shifted to the investment farms. We found three key characteristics responsible for the different bargaining power of the two actor groups: dependency on natural resources, education and knowledge, and dependency on government support. We conclude that not only the struggle for land but also the directly linked struggle for water is led by diverging interests, which are determined by diverging power resources.

  13. World trends from 2017

    Directory of Open Access Journals (Sweden)

    Janković Slobodan

    2016-01-01

    Full Text Available Issue of prognosis, analyses of future trends is companion to statecraft, political, economic and military planning. How we plan, what does IR says about scientific prognosis. Jankovic starts with this set of issues in order to pass into prognosis itself based on observable world trends. He claims that European Union has entered its climax comparing it foreign policy situation with that of war situation of Third Reich in 1943. Article is divided in five parts. After presenting and criticizing Anglo-American approach in prognosis, he starts with analysis of the world order changes, of EU trends, Middle, Far East and some trends regarding Africa. Author presents macro trends in North - West Pacific, in Israel-Palestine, in Syria, Iraq, in Europe.

  14. Steady and transient regimes in hydropower plants

    Science.gov (United States)

    Gajic, A.

    2013-12-01

    Hydropower plant that has been in operation for about 30 years has to be reconstructed. They have already installed 12 Kaplan turbines, the largest in the world at that time. The existing CAM relationship was determined based on hydraulic model tests and checked by efficiency on-site tests. It was also tested based on turbine bearing vibrations. In order to discover vibrations and long cracks on stay vanes detailed on-site measurements were performed. Influence of the modification of the trailing edges on the dynamic stresses of the stay vanes is also shown. In order to improve power output transient regimes were analyzed, both experimentally and numerically. Reversible hydropower plant, a pioneer in Europe since it was the first Pump storage power plant constructed with the highest head pump-turbines in the world. Analyses of transient regimes discover some problems with S-shaped characteristics coupled with non-symmetrical penstock.

  15. Steady and transient regimes in hydropower plants

    International Nuclear Information System (INIS)

    Gajic, A

    2013-01-01

    Hydropower plant that has been in operation for about 30 years has to be reconstructed. They have already installed 12 Kaplan turbines, the largest in the world at that time. The existing CAM relationship was determined based on hydraulic model tests and checked by efficiency on-site tests. It was also tested based on turbine bearing vibrations. In order to discover vibrations and long cracks on stay vanes detailed on-site measurements were performed. Influence of the modification of the trailing edges on the dynamic stresses of the stay vanes is also shown. In order to improve power output transient regimes were analyzed, both experimentally and numerically. Reversible hydropower plant, a pioneer in Europe since it was the first Pump storage power plant constructed with the highest head pump-turbines in the world. Analyses of transient regimes discover some problems with S-shaped characteristics coupled with non-symmetrical penstock

  16. Recent Activities on Global Nuclear Safety Regime

    International Nuclear Information System (INIS)

    Cho, Kun-Woo; Park, Jeong-Seop; Kim, Do-Hyoung

    2006-01-01

    Recently, rapid progress on the globalization of the nuclear safety issues is being made in IAEA (International Atomic Energy Agency) and its member states. With the globalization, the need for international cooperation among international bodies and member states continues to grow for resolving these universal nuclear safety issues. Furthermore, the importance of strengthening the global nuclear safety regime is emphasized through various means, such as efforts in application of IAEA safety standards to all nuclear installations in the world and in strengthening the code of conduct and the convention on nuclear safety. In this regards, it is important for us to keep up with the activities related with the global nuclear safety regime as an IAEA member state and a leading country in nuclear safety regulation

  17. Regimes de espaço

    Directory of Open Access Journals (Sweden)

    Eric Landowski

    2015-06-01

    Full Text Available Space Regimes - Based on a general model of interaction, the present analysis attempts to account for the diversity of the ways space may be apprehended in lived experience. It leads to the definition of four configurations that correspond to as many regimes of relation with the environing world. The conventional space of the circulation of values takes the archetypical shape of the net (incarnated today by Internet. The operational space is that of our dealing with objects within a material environment seen as a tissue of stable and intelligible relations. The experienced space of bodies’ movement, to which one may give as an emblem the spiral, expresses the dynamics of sensitive relationships between the self and the other. The existential space is that of our presence in a universe without boundaries, which no one can properly represent oneself but that nonetheless haunts art and thought: its figure is the abyss.

  18. Searching for resilience: addressing the impacts of changing disturbance regimes on forest ecosystem services

    Science.gov (United States)

    Seidl, Rupert; Spies, Thomas A.; Peterson, David L.; Stephens, Scott L.; Hicke, Jeffrey A.

    2016-01-01

    Summary 1. The provisioning of ecosystem services to society is increasingly under pressure from global change. Changing disturbance regimes are of particular concern in this context due to their high potential impact on ecosystem structure, function and composition. Resilience-based stewardship is advocated to address these changes in ecosystem management, but its operational implementation has remained challenging. 2. We review observed and expected changes in disturbance regimes and their potential impacts on provisioning, regulating, cultural and supporting ecosystem services, concentrating on temperate and boreal forests. Subsequently, we focus on resilience as a powerful concept to quantify and address these changes and their impacts, and present an approach towards its operational application using established methods from disturbance ecology. 3. We suggest using the range of variability concept – characterizing and bounding the long-term behaviour of ecosystems – to locate and delineate the basins of attraction of a system. System recovery in relation to its range of variability can be used to measure resilience of ecosystems, allowing inferences on both engineering resilience (recovery rate) and monitoring for regime shifts (directionality of recovery trajectory). 4. It is important to consider the dynamic nature of these properties in ecosystem analysis and management decision-making, as both disturbance processes and mechanisms of resilience will be subject to changes in the future. Furthermore, because ecosystem services are at the interface between natural and human systems, the social dimension of resilience (social adaptive capacity and range of variability) requires consideration in responding to changing disturbance regimes in forests. 5. Synthesis and applications. Based on examples from temperate and boreal forests we synthesize principles and pathways for fostering resilience to changing disturbance regimes in ecosystem management. We

  19. Supersonic free jet, molecular free regime

    International Nuclear Information System (INIS)

    Sanna, G.; Tomassetti, G.

    1999-01-01

    The structure of the free jet emitted by a converging nozzle as obtained by the method of characteristics by Ashkenas and Sherman is described in details. In particular the dependence of the field variable by the distance from the nozzle is given. The transition from continuum to molecular free regime is then considered and the sudden freeze approximation is introduced. The processing of monoatomic and polyatomic gasses is also considered [it

  20. Dynamic Regime of Ignition of Solid Propellant

    Directory of Open Access Journals (Sweden)

    Zolotorev Nikolay

    2016-01-01

    Full Text Available This article presents a dynamic regime of exposure of the radiant flux on the sample of gun-cotton. Obtained time the ignition of gun-cotton in the heating conditions of increasing heat flux in the range from 0.2 W/cm2 to 22 W/cm2. A comparison of the delay times of the ignition when heated variable and constant heat flux.

  1. Resource Windfalls, Political Regimes, and Political Stability

    OpenAIRE

    Francesco Caselli; Andrea Tesei

    2011-01-01

    We study theoretically and empirically whether natural resource windfalls affect political regimes. We document the following regularities. Natural resource windfalls have no effect on the political system when they occur in democracies. However, windfalls have significant political consequences in autocracies. In particular, when an autocratic country receives a positive shock to its flow of resource rents it responds by becoming even more autocratic. Furthermore, there is heterogeneity in t...

  2. Deuteron structure in the deep inelastic regime

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Canal, C.A.; Tarutina, T. [Universidad Nacional de La Plata, IFLP/CONICET y Departamento de Fisica, La Plata (Argentina); Vento, V. [Universidad de Valencia-CSIC, Departamento de Fisica Teorica-IFIC, Burjassot (Valencia) (Spain)

    2017-06-15

    We study nuclear effects in the deuteron in the deep inelastic regime using the newest available data. We put special emphasis on their Q{sup 2} dependence. The study is carried out using a scheme which parameterizes, in a simple manner, these effects by changing the proton and neutron stucture functions in medium. The result of our analysis is compared with other recent proposals. We conclude that precise EMC ratios cannot be obtained without considering the nuclear effects in the deuteron. (orig.)

  3. Proliferation Control Regimes: Background and Status

    Science.gov (United States)

    2012-10-25

    States has signed such agreements with Antigua and Barbuda, the Bahamas, Belize, Croatia, Cyprus, Liberia, Malta, the Marshall Islands , Mongolia...Chemical Weapons Convention (CWC), the Biological and Toxin Weapons Convention (BWC), and the Australia Group. The informal Australia Group...biological agents or toxins “of types and in quantities that have no justification for peaceful purposes.” The missile nonproliferation regime is founded not

  4. A regime legitimacy explanation of African peacekeeping

    OpenAIRE

    Ross, Matthew.

    2011-01-01

    Approved for public release; distribution is unlimited. The American military needs to understand what incentivizes some African nations to participate in peacekeeping in order to strengthen the incentive structure so that high levels of peacekeeping will continue. The main argument advanced in this thesis is that regimes that are attempting to increase their structural legitimacy are more likely to volunteer for peacekeeping missions to gain international political legitimacy, as well as ...

  5. Symmetric vs. asymmetric punishment regimes for bribery

    OpenAIRE

    Engel, Christoph; Goerg, Sebastian J.; Yu, Gaoneng

    2012-01-01

    In major legal orders such as UK, the U.S., Germany, and France, bribers and recipients face equally severe criminal sanctions. In contrast, countries like China, Russia, and Japan treat the briber more mildly. Given these differences between symmetric and asymmetric punishment regimes for bribery, one may wonder which punishment strategy is more effective in curbing corruption. For this purpose, we designed and ran a lab experiment in Bonn (Germany) and Shanghai (China) with exactly the same...

  6. Stark shift and g-factor tuning in nanowires with Rashba effect

    Energy Technology Data Exchange (ETDEWEB)

    Alhaddad, Iman; Habanjar, Khulud [Department of Physics, Faculty of Science, Beirut Arab University, P.O. Box 11, 5020 Riad El Solh, 11072809 - Beirut (Lebanon); Sakr, M.R., E-mail: msakr@alexu.edu.eg [Department of Physics, Faculty of Science, Beirut Arab University, P.O. Box 11, 5020 Riad El Solh, 11072809 - Beirut (Lebanon); Department of Physics, Faculty of Science, Alexandria University, Moharram Bek, Alexandria 21511 (Egypt)

    2015-10-15

    We report on the Stark shift of the energy subbands and the possibility of tuning the g-factor of electrons in nanowires subjected to external magnetic field. The electric field is applied along the direction of quantum confinement. Our analysis is based on numerical and perturbation calculations in the weak Rashba regime. For in-plane magnetic fields, the Stark shift is rigid and depends on the square of the electric field. Such rigid shift results in a field independent g-factor. Perpendicular magnetic fields induce a similar Stark shift accompanied by a lateral displacement of the energy spectra that is linear in the electric field. In this case, the g-factor shows square dependence on weak electric fields that varies with the subband index. However, in strong electric fields, the g-factor becomes subband independent and varies linearly with the field. - Highlights: • Energy spectra of electrons in nanowires are calculated in the weak Rashba regime. • For in-plane magnetic field, the Stark shift is rigid and the g-factor cannot be tuned. • Perpendicular magnetic fields add lateral displacement to the Stark shift. • The g-factor can be tuned by external electric field in this case. • The tuning of the g-factor is linear and unique for all subbands at high fields.

  7. Stark shift and g-factor tuning in nanowires with Rashba effect

    International Nuclear Information System (INIS)

    Alhaddad, Iman; Habanjar, Khulud; Sakr, M.R.

    2015-01-01

    We report on the Stark shift of the energy subbands and the possibility of tuning the g-factor of electrons in nanowires subjected to external magnetic field. The electric field is applied along the direction of quantum confinement. Our analysis is based on numerical and perturbation calculations in the weak Rashba regime. For in-plane magnetic fields, the Stark shift is rigid and depends on the square of the electric field. Such rigid shift results in a field independent g-factor. Perpendicular magnetic fields induce a similar Stark shift accompanied by a lateral displacement of the energy spectra that is linear in the electric field. In this case, the g-factor shows square dependence on weak electric fields that varies with the subband index. However, in strong electric fields, the g-factor becomes subband independent and varies linearly with the field. - Highlights: • Energy spectra of electrons in nanowires are calculated in the weak Rashba regime. • For in-plane magnetic field, the Stark shift is rigid and the g-factor cannot be tuned. • Perpendicular magnetic fields add lateral displacement to the Stark shift. • The g-factor can be tuned by external electric field in this case. • The tuning of the g-factor is linear and unique for all subbands at high fields

  8. ACCESSORIES OF FISCAL OBLIGATION. LEGAL REGIME

    Directory of Open Access Journals (Sweden)

    RADA POSTOLACHE

    2012-05-01

    Full Text Available The interest – which is an institution typical to private law, has been taken over by the fiscal field and adapted to the specific features of fiscal obligation – being defined by its imperative legal regime, which has at the least the following characteristic elements: unitary character, imposed legal percentage, compulsory demand of interest, automatic application. In order to render responsible fiscal debtors, the lawmaker has reintroduced, as an accessory of fiscal obligation, delayed payment penalties, which have a distinct nature and legal regime, but without the principle non bis in idem being transgressed. Our study aims to establish the legal regime ofaccessories typical to fiscal obligation, from the perspective of special normative acts, but also of the common law within the field – Civil Code and Government Ordinance No. 13/2011 – by pointing out at the same time both the particular circumstances and procedural ones regulated by the Fiscal Procedure Code, shedding light upon the controversial legal nature of accessories.

  9. "International regime for advancing lunar development"

    Science.gov (United States)

    Beldavs, VZ

    2017-09-01

    A specific concern regarding the Moon Treaty is the provision for sharing the wealth gained from space with developing countries that have not invested and taken risks in making possible space materials utilization. Article 11, par. 7 states "The main purposes of the international regime to be established shall include: (a) The orderly and safe development of the natural resources of the moon; (b) The rational management of those resources; (c) The expansion of opportunities in the use of those resources; (d) An equitable sharing by all States Parties in the benefits derived from those resources, whereby the interests and needs of the developing countries, as well as the efforts of those countries which have contributed either directly or indirectly to the exploration of the moon, shall be given special consideration." Whether the Moon Treaty in its present form or modified to be acceptable to more parties or the Moon Treaty is ignored, the language of Article 11, paragraph 7 can be used to construct an international regime for lunar development that can meet the requirements of commercial business as well as of states that provide support for lunar development as well as developing countries that may have played a modest role in making lunar development possible. This paper will consider options for constructing an international regime for lunar development.

  10. Detecting spatial regimes in ecosystems | Science Inventory ...

    Science.gov (United States)

    Research on early warning indicators has generally focused on assessing temporal transitions with limited application of these methods to detecting spatial regimes. Traditional spatial boundary detection procedures that result in ecoregion maps are typically based on ecological potential (i.e. potential vegetation), and often fail to account for ongoing changes due to stressors such as land use change and climate change and their effects on plant and animal communities. We use Fisher information, an information theory based method, on both terrestrial and aquatic animal data (US Breeding Bird Survey and marine zooplankton) to identify ecological boundaries, and compare our results to traditional early warning indicators, conventional ecoregion maps, and multivariate analysis such as nMDS (non-metric Multidimensional Scaling) and cluster analysis. We successfully detect spatial regimes and transitions in both terrestrial and aquatic systems using Fisher information. Furthermore, Fisher information provided explicit spatial information about community change that is absent from other multivariate approaches. Our results suggest that defining spatial regimes based on animal communities may better reflect ecological reality than do traditional ecoregion maps, especially in our current era of rapid and unpredictable ecological change. Use an information theory based method to identify ecological boundaries and compare our results to traditional early warning

  11. QCD in the {delta}-regime

    Energy Technology Data Exchange (ETDEWEB)

    Bietenholz, W. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias Nucleares; Cundy, N. [Seoul National Univ. (Korea, Republic of). Lattice Gauge Theory Research Center; Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, R.; Zanotti, J.M. [Edinburgh Univ. (United Kingdom). School of Physics; Nakamura, Y. [Tsukuba Univ., Ibaraki (Japan). Center for Computational Sciences; Pleiter, D. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Schierholz, G. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-03-15

    The {delta}-regime of QCD is characterised by light quarks in a small spatial box, but a large extent in (Euclidean) time. In this setting a specific variant of chiral perturbation theory - the {delta}-expansion - applies, based on a quantum mechanical treatment of the quasi onedimensional system. In particular, for vanishing quark masses one obtains a residual pion mass M{sup R}{sub {pi}}, which has been computed to the third order in the {delta}-expansion. A comparison with numerical measurements of this residual mass allows for a new determination of some Low Energy Constants, which appear in the chiral Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in the {delta}-regime. This is very tedious, but results compatible with the predictions for M{sup R}{sub {pi}} have been obtained. Then we show that an extrapolation of pion masses measured in a larger volume towards the {delta}-regime leads to good agreement with the theoretical predictions. From those results, we also extract a value for the (controversial) sub-leading Low Energy Constant anti l{sub 3}. (orig.)

  12. QCD in the δ-regime

    International Nuclear Information System (INIS)

    Bietenholz, W.; Rakow, P.E.L.

    2011-03-01

    The δ-regime of QCD is characterised by light quarks in a small spatial box, but a large extent in (Euclidean) time. In this setting a specific variant of chiral perturbation theory - the δ-expansion - applies, based on a quantum mechanical treatment of the quasi onedimensional system. In particular, for vanishing quark masses one obtains a residual pion mass M R π , which has been computed to the third order in the δ-expansion. A comparison with numerical measurements of this residual mass allows for a new determination of some Low Energy Constants, which appear in the chiral Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in the δ-regime. This is very tedious, but results compatible with the predictions for M R π have been obtained. Then we show that an extrapolation of pion masses measured in a larger volume towards the δ-regime leads to good agreement with the theoretical predictions. From those results, we also extract a value for the (controversial) sub-leading Low Energy Constant anti l 3 . (orig.)

  13. British Columbia's new coalbed methane royalty regime

    International Nuclear Information System (INIS)

    Molinski, D.

    2002-01-01

    The British Columbia Ministry of Energy and Mines is promoting the development of the coalbed methane (CBM) industry in the province in order to make CBM a viable and competitive investment option for industry. It is establishing a regulatory and fiscal regime for CBM development. Issues of concern regarding CBM development include water production, gas production rates, well numbers, and marginal economics. The features of the CBM royalty regime include a new producer cost of service allowance, the creation of a CBM royalty tax bank to collect excess PCOS allowances, and a royalty tax credit for wells drilled by the end of February, 2004. The marginal well adjustment factor threshold has been raised from 180 mcf per day to 600 mcf per day for CBM only. It was noted that royalties will probably not be payable for several years following the first commercial well because royalties are very depending on capital and operating costs, local infrastructure and price. Royalty regimes cannot save CBM from low gas prices, poor resources or economics. 2 figs

  14. Private actor accountability on international regimes

    Directory of Open Access Journals (Sweden)

    Wahyudi Purnomo

    2017-12-01

    Full Text Available Public-Private Partnerships (PPPs have emerged along with the growing role of corporations in global development. One of the largest forms of PPP today is the UN Global Compact. The UN Global Compact involves of companies, NGOs, IGOs and state governments. All of them are trying to realize globalization with a more humanist face with attention to the protection of human rights, environment, labor standards and anti-corruption. Engaging private actors in global governance, The UN Global Compact raises many issues such as power, authority, and legitimacy. The effort to tackle it all is to increase PPP accountability. This research seeks to describe what efforts can be made to enhance private accountability within the international regime. The research undertaken is a descriptive study, focuses on public-private partnerships in the UN Global Compact regime. The study found that there were two attempts that could be done. First, by involving the stakeholders in the development of procedures, mechanisms, reporting and monitoring associated with trying to improve the company’s reputation. Second, by looking at corporate relations as agent and UN Global Compact as principal in principal-agent relation in the international regime.

  15. Channel evolution under changing hydrological regimes in anabranching reaches downstream of the Three Gorges Dam

    Science.gov (United States)

    Han, Jianqiao; Zhang, Wei; Yuan, Jing; Fan, Yongyang

    2018-03-01

    Elucidating the influence of dams on fluvial processes can benefit river protection and basin management. Based on hydrological and topographical data, we analyzed channel evolution in anabranching reaches under changing hydrological regimes influenced by the Three Gorges Dam. The main conclusions are as follows: 1) the channels of specific anabranching reaches were defined as flood trend channels or low-flow trend channels according to the distribution of their flow characteristics. The anabranching reaches were classified as T1 or T2. The former is characterized by the correspondence between the flood trend and branch channels, and the latter is characterized by the correspondence between the flood trend and main channels; 2) on the basis of the new classification, the discrepant patterns of channel evolution seen in anabranching reaches were unified into a pattern that showed flood trend channels shrinking and low-flow trend channels expanding; 3) flood abatement and the increased duration of moderate flow discharges are the main factors that affect channel adjustments in anabranching reaches after dam construction; and 4) in the next few decades, the pattern of channel evolution will remain the same as that of the Three Gorges Dam operation. That is, the morphology will fully adapt to a flow with a low coefficient of variation. Our results are of interest in the management of the Yangtze River and other rivers influenced by dams.

  16. Masculinity in Indonesian Popular Culture in the Early Era of the New Order Regime

    Directory of Open Access Journals (Sweden)

    Ferry Fauzi Hermawan

    2017-05-01

    Full Text Available This study aimed to identify the forms of masculinity in the Indonesian popular culture in the beginning of New Order regime. This study was based on the two novels: Cross Mama and Kekasih-Kekasih Gelap, written by Motinggo Busye. The analysis used new historicism theory proposed by Stephen Greenblatt. The analysis also considered various cultural contexts emerged in 1970s. The results show three shared trends in the novels. The first trend shows that the masculinity tends to be represented by both men worshiping patriarchal values such as the myth of woman’s virginity and men perceiving woman as a sexual object. The second trend shows that masculinity is stereotyped based on masculinity, power, and male dominance. The third trend shows that masculinity relates to various products of mass culture at the time. This last trend shows that in that era, the ideal male figure is represented as the one who: (1 is sexually active with many women, (2 has a muscular body, (3 has a handsome look, and (4 has a financial capability. Besides the shared three trends, the result also shows that the texts in the novels do not only reflect the cultural situations in the 60’s and 70’s but also contribute in shaping the social values of thecultural situations. Normal 0 false false false IN X-NONE X-NONE  

  17. Leadership Shifts in Changing Field

    Science.gov (United States)

    Zubrzycki, Jaclyn

    2013-01-01

    As groups representing local and state education players struggle to remain relevant in a policy conversation often dominated by foundations, think tanks, new advocacy groups, and political and business figures, a shift in leadership has been under way at major associations. Most of the changes have come as part of the natural churn; former…

  18. Crichton's phase-shift ambiguity

    NARCIS (Netherlands)

    Atkinson, D.; Johnson, P.W.; Mehta, N.; Roo, M. de

    1973-01-01

    A re-examination of the SPD phase-shift ambiguity is made with a view to understanding certain singular features of the elastic unitarity constraint. An explicit solution of Crichton's equations is presented, and certain features of this solution are displayed graphically. In particular, it is shown

  19. Environmental Protection: a shifting focus

    NARCIS (Netherlands)

    Dr. ir. Jan Venselaar

    2004-01-01

    The last two decades have seen a fundamental change in the way chemistry handles environmental issues. A shift in focus has occurred from 'end-of-pipe' to prevention and process integration. Presently an even more fundamental change is brought about by the need for sustainable development. It is

  20. Anthropometric changes and fluid shifts

    Science.gov (United States)

    Thornton, W. E.; Hoffler, G. W.; Rummel, J. A.

    1974-01-01

    Several observations of body size, shape, posture, and configuration were made to document changes resulting from direct effects of weightlessness during the Skylab 4 mission. After the crewmen were placed in orbit, a number of anatomical and anthropometric changes occurred including a straightening of the thoracolumbar spine, a general decrease in truncal girth, and an increase in height. By the time of the earliest in-flight measurement on mission day 3, all crewmen had lost more than two liters of extravascular fluid from the calf and thigh. The puffy facies, the bird legs effect, the engorgement of upper body veins, and the reduced volume of lower body veins were all documented with photographs. Center-of-mass measurements confirmed a fluid shift cephalad. This shift remained throughout the mission until recovery, when a sharp reversal occurred; a major portion of the reversal was completed in a few hours. The anatomical changes are of considerable scientific interest and of import to the human factors design engineer, but the shifts of blood and extravascular fluid are of more consequence. It is hypothesized that the driving force for the fluid shift is the intrinsic and unopposed lower limb elasticity that forces venous blood and then other fluid cephalad.

  1. Overnight shift work: factors contributing to diagnostic discrepancies.

    Science.gov (United States)

    Hanna, Tarek N; Loehfelm, Thomas; Khosa, Faisal; Rohatgi, Saurabh; Johnson, Jamlik-Omari

    2016-02-01

    The aims of the study are to identify factors contributing to preliminary interpretive discrepancies on overnight radiology resident shifts and apply this data in the context of known literature to draw parallels to attending overnight shift work schedules. Residents in one university-based training program provided preliminary interpretations of 18,488 overnight (11 pm–8 am) studies at a level 1 trauma center between July 1, 2013 and December 31, 2014. As part of their normal workflow and feedback, attendings scored the reports as major discrepancy, minor discrepancy, agree, and agree--good job. We retrospectively obtained the preliminary interpretation scores for each study. Total relative value units (RVUs) per shift were calculated as an indicator of overnight workload. The dataset was supplemented with information on trainee level, number of consecutive nights on night float, hour, modality, and per-shift RVU. The data were analyzed with proportional logistic regression and Fisher's exact test. There were 233 major discrepancies (1.26 %). Trainee level (senior vs. junior residents; 1.08 vs. 1.38 %; p performance. Increased workload affected more junior residents' performance, with R3 residents performing significantly worse on busier nights. Hour of the night was not significantly associated with performance, but there was a trend toward best performance at 2 am, with subsequent decreased accuracy throughout the remaining shift hours. Improved performance occurred after the first six night float shifts, presumably as residents acclimated to a night schedule. As overnight shift work schedules increase in popularity for residents and attendings, focused attention to factors impacting interpretative accuracy is warranted.

  2. JT-60U high performance regimes

    International Nuclear Information System (INIS)

    Ishida, S.

    1999-01-01

    High performance regimes of JT-60U plasmas are presented with an emphasis upon the results from the use of a semi-closed pumped divertor with W-shaped geometry. Plasma performance in transient and quasi steady states has been significantly improved in reversed shear and high- βp regimes. The reversed shear regime elevated an equivalent Q DT eq transiently up to 1.25 (n D (0)τ E T i (0)=8.6x10 20 m-3·s·keV) in a reactor-relevant thermonuclear dominant regime. Long sustainment of enhanced confinement with internal transport barriers (ITBs) with a fully non-inductive current drive in a reversed shear discharge was successfully demonstrated with LH wave injection. Performance sustainment has been extended in the high- bp regime with a high triangularity achieving a long sustainment of plasma conditions equivalent to Q DT eq ∼0.16 (n D (0)τ E T i (0)∼1.4x10 20 m -3 ·s·keV) for ∼4.5 s with a large non-inductive current drive fraction of 60-70% of the plasma current. Thermal and particle transport analyses show significant reduction of thermal and particle diffusivities around ITB resulting in a strong Er shear in the ITB region. The W-shaped divertor is effective for He ash exhaust demonstrating steady exhaust capability of τ He */τ E ∼3-10 in support of ITER. Suppression of neutral back flow and chemical sputtering effect have been observed while MARFE onset density is rather decreased. Negative-ion based neutral beam injection (N-NBI) experiments have created a clear H-mode transition. Enhanced ionization cross- section due to multi-step ionization processes was confirmed as theoretically predicted. A current density profile driven by N-NBI is measured in a good agreement with theoretical prediction. N-NBI induced TAE modes characterized as persistent and bursting oscillations have been observed from a low hot beta of h >∼0.1-0.2% without a significant loss of fast ions. (author)

  3. An empirical comparison of alternate regime-switching models for electricity spot prices

    Energy Technology Data Exchange (ETDEWEB)

    Janczura, Joanna [Hugo Steinhaus Center, Institute of Mathematics and Computer Science, Wroclaw University of Technology, 50-370 Wroclaw (Poland); Weron, Rafal [Institute of Organization and Management, Wroclaw University of Technology, 50-370 Wroclaw (Poland)

    2010-09-15

    One of the most profound features of electricity spot prices are the price spikes. Markov regime-switching (MRS) models seem to be a natural candidate for modeling this spiky behavior. However, in the studies published so far, the goodness-of-fit of the proposed models has not been a major focus. While most of the models were elegant, their fit to empirical data has either been not examined thoroughly or the signs of a bad fit ignored. With this paper we want to fill the gap. We calibrate and test a range of MRS models in an attempt to find parsimonious specifications that not only address the main characteristics of electricity prices but are statistically sound as well. We find that the best structure is that of an independent spike 3-regime model with time-varying transition probabilities, heteroscedastic diffusion-type base regime dynamics and shifted spike regime distributions. Not only does it allow for a seasonal spike intensity throughout the year and consecutive spikes or price drops, which is consistent with market observations, but also exhibits the 'inverse leverage effect' reported in the literature for spot electricity prices. (author)

  4. An empirical comparison of alternate regime-switching models for electricity spot prices

    International Nuclear Information System (INIS)

    Janczura, Joanna; Weron, Rafal

    2010-01-01

    One of the most profound features of electricity spot prices are the price spikes. Markov regime-switching (MRS) models seem to be a natural candidate for modeling this spiky behavior. However, in the studies published so far, the goodness-of-fit of the proposed models has not been a major focus. While most of the models were elegant, their fit to empirical data has either been not examined thoroughly or the signs of a bad fit ignored. With this paper we want to fill the gap. We calibrate and test a range of MRS models in an attempt to find parsimonious specifications that not only address the main characteristics of electricity prices but are statistically sound as well. We find that the best structure is that of an independent spike 3-regime model with time-varying transition probabilities, heteroscedastic diffusion-type base regime dynamics and shifted spike regime distributions. Not only does it allow for a seasonal spike intensity throughout the year and consecutive spikes or price drops, which is consistent with market observations, but also exhibits the 'inverse leverage effect' reported in the literature for spot electricity prices. (author)

  5. Autonomia e relevância dos regimes The autonomy and relevance of regimes

    Directory of Open Access Journals (Sweden)

    Gustavo Seignemartin de Carvalho

    2005-12-01

    Full Text Available Teorias institucionalistas na disciplina de relações internacionais usualmente definem regimes como um conjunto de normas e regras formais ou informais que permitem a convergência de expectativas ou a padronização do comportamento de seus participantes em uma determinada área de interesses com o objetivo de resolver problemas de coordenação que tenderiam a resultados não pareto-eficientes. Como estas definições baseadas meramente na "eficiência" dos regimes não parecem suficientes para explicar sua efetividade, o presente artigo propõe uma definição diferente para regimes: a de arranjos políticos que permitem a redistribuição dos ganhos da cooperação pelos participantes em uma determinada área de interesses em um contexto de interdependência. Regimes possuiriam efetividade pela sua autonomia e relevância, ou seja, por possuírem existência objetiva autônoma da de seus participantes e por influenciarem seu comportamento e expectativas de maneiras que não podem ser reduzidas à ação individual de nenhum deles. O artigo inicia-se com uma breve discussão sobre as dificuldades terminológicas associadas ao estudo de regimes e a definição dos conceitos de autonomia e relevância. Em seguida, classifica os diversos autores participantes do debate em duas perspectivas distintas, uma que nega (não-autonomistas e outra que atribui (autonomistas aos regimes autonomia e relevância, e faz uma breve análise dos autores e tradições mais significativos para o debate, aprofundando-se nos autonomistas e nos argumentos que reforçam a hipótese aqui apresentada. Ao final, o artigo propõe uma decomposição analítica dos regimes nos quatro elementos principais que lhes propiciam autonomia e relevância: normatividade, atores, especificidade da área de interesses e interdependência complexa com o contexto.Regimes are defined by institutionalist theories in the discipline of International Relations as formal or informal sets

  6. Multiple climate regimes in an idealized lake-ice-atmosphere model

    Science.gov (United States)

    Sugiyama, Noriyuki; Kravtsov, Sergey; Roebber, Paul

    2018-01-01

    In recent decades, the Laurentian Great Lakes have undergone rapid surface warming with the summertime trends substantially exceeding the warming rates of surrounding land. Warming of the deepest (Lake Superior) was the strongest, and that of the shallowest (Lake Erie)—the weakest of all lakes. To investigate the dynamics of accelerated lake warming, we considered single-column and multi-column thermodynamic lake-ice models coupled to an idealized two-layer atmosphere. The variable temperature of the upper atmospheric layer—a proxy for the large-scale atmospheric forcing—consisted, in the most general case, of a linear trend mimicking the global warming and atmospheric interannual variability, both on top of the prescribed seasonal cycle of the upper-air temperature. The atmospheric boundary layer of the coupled model exchanged heat with the lake and exhibited lateral diffusive heat transports between the adjacent atmospheric columns. In simpler single-column models, we find that, for a certain range of periodic atmospheric forcing, each lake possesses two stable equilibrium seasonal cycles, which we call "regimes"—with and without lake-ice occurrence in winter and with corresponding cold and warm temperatures in the following summer, respectively, all under an identical seasonally varying external forcing. Deeper lakes exhibit larger differences in their summertime surface water temperature between the warm and cold regimes, due to their larger thermal and dynamical inertia. The regime behavior of multi-column coupled models is similar but more complex, and in some cases, they admit more than two stable equilibrium seasonal cycles, with varying degrees of wintertime ice-cover. The simulated lake response to climate change in the presence of the atmospheric noise rationalizes the observed accelerated warming of the lakes, the correlation between wintertime ice cover and next summer's lake-surface temperature, as well as higher warming trends of the

  7. Night shift work and stomach cancer risk in the MCC-Spain study.

    Science.gov (United States)

    Gyarmati, Georgina; Turner, Michelle C; Castaño-Vinyals, Gemma; Espinosa, Ana; Papantoniou, Kyriaki; Alguacil, Juan; Costas, Laura; Pérez-Gómez, Beatriz; Martin Sanchez, Vicente; Ardanaz, Eva; Moreno, Victor; Gómez-Acebo, Inés; Fernández-Tardon, Guillermo; Villanueva Ballester, Vicent; Capelo, Rocio; Chirlaque, Maria-Dolores; Santibáñez, Miguel; Pollán, Marina; Aragonés, Nuria; Kogevinas, Manolis

    2016-08-01

    Night shift work has been classified as a probable human carcinogen by the International Agency for Research on Cancer, based on experimental studies and limited evidence on human breast cancer risk. Evidence at other cancer sites is scarce. We evaluated the association between night shift work and stomach cancer risk in a population-based case-control study. A total of 374 incident stomach adenocarcinoma cases and 2481 population controls were included from the MCC-Spain study. Detailed data on lifetime night shift work were collected including permanent and rotating shifts, and their cumulative duration (years). Adjusted unconditional logistic regression models were used in analysis. A total of 25.7% of cases and 22.5% of controls reported ever being a night shift worker. There was a weak positive, non-significant association between ever having had worked for at least 1 year in permanent night shifts and stomach cancer risk compared to never having worked night shifts (OR=1.2, 95% CI 0.9 to 1.8). However, there was an inverse 'U' shaped relationship with cumulative duration of permanent night shifts, with the highest risk observed in the intermediate duration category (OR 10-20 years=2.0, 95% CI 1.1 to 3.6) (p for trend=0.19). There was no association with ever having had worked in rotating night shifts (OR=0.9, 95% CI 0.6 to 1.2) and no trend according to cumulative duration (p for trend=0.68). We found no clear evidence concerning an association between night shift work and stomach cancer risk. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  8. Multiple long-term trends and trend reversals dominate environmental conditions in a man-made freshwater reservoir

    Czech Academy of Sciences Publication Activity Database

    Znachor, Petr; Nedoma, Jiří; Hejzlar, Josef; Seďa, Jaromír; Kopáček, Jiří; Boukal, D.; Mrkvička, Tomáš

    2018-01-01

    Roč. 624, May (2018), s. 24-33 ISSN 0048-9697 R&D Projects: GA ČR GA15-13750S; GA MŠk(CZ) LM2015075 Institutional support: RVO:60077344 Keywords : model selection * piecewise regression * regime shift * time series Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 4.900, year: 2016

  9. Latitudinal gradients in the productivity of European migrant warblers have not shifted northwards during a period of climate change.

    NARCIS (Netherlands)

    Eglington, S; Juliard, R; Gargallo, G; Van der Jeugd, Henk; Pearce Higgins, J; Baillie, S.R.; Robinson, R.A.

    2015-01-01

    Aim As global temperatures have increased, many species distributions have exhibited polewards shifts, a trend that is predicted to continue in future decades. However, the mechanisms underlying such shifts are not well understood. Here we quantify the impact of large-scale variation in temperature

  10. Advanced technologies: Trends and implications for security

    International Nuclear Information System (INIS)

    Shaw, A.

    1990-01-01

    As the world moves towards the close of the twentieth century, three technological trends will strongly influence security. In order of importance they are: first, the increasing globalization of the ability to develop and use high technology, much of which has both civilian and military applications; secondly, the broad dissemination of militarily-relevant technology world-wide; and thirdly, the continued development by the United States and the USSR (and a few other nations) of advanced technology for military applications. The military balance between the super-Powers and their allies has been strongly rooted in advancing military technology. Great changes in technology have resulted in adjustments -mostly in limited aspects such as the armour/ anti-armour balance - but have not caused it to change wildly. This seems likely to remain the case for the foreseeable future. There are arguments that Western technology has been a prime causative factor behind Soviet willingness to engage in negotiations to reduce forces. They claim that fear of the Strategic Defense Initiative is behind progress in the Strategic Arms Reduction Talks, and that perceived Western mastery of the technology for systems combining quick reaction, deep strike and high kill probabilities led the Soviet Union to reassess its potential for a successful land campaign in Europe. If current arms control negotiations are successful, the momentum is maintained, and other political changes take hold, the military balance could be taken to a point where ft would not be very sensitive to technological change. One should be aware that the arms control negotiations are very complex, primarily because of technological issues, and we should not yet bank on it all working out well. If it fails, the military technical competition will heat up again. Even under a strict arms control regime we can expect the competition to continue as each side seeks to develop counters to what ft sees as the other side

  11. FISHER INFORMATION OF DYNAMIC REGIME TRANSITIONS IN ECOLOGICAL SYSTEMS

    Science.gov (United States)

    Ecosystems often exhibit transitions between multiple dynamic regimes (or steady states). As ecosystems experience perturbations of varying regularity and intensity, they may either remain within the state space neighborhood of the current regime, or ?flip? into the neighborhood ...

  12. The influence of climatic and anthropogenic factors on hydrological regime of rivers at the south of Krasnoyarsk Krai

    Directory of Open Access Journals (Sweden)

    T. A. Burenia

    2018-04-01

    Full Text Available Despite a large number of publications covering various aspects of the influence of climatic factors on runoff, this direction in hydrological research acquires a new meaning in connection with the increase in anthropogenic pressure on river systems. In order to identify regional and local features of the hydrological regime of the rivers in Sayan mountain region, the spatial and temporal dynamics of runoff of the main rivers in the study area were analyzed; the analysis of river flow trends against the backdrop of climate change and forest management in the drain areas was performed. Studies have shown that the revealed trends in the annual runoff of the studied rivers differ in type and in magnitude. The hydrological regime of the rivers with the negative trend of annual runoff is determined by the general nature of the humidification of the territory, which overrides the influence of all other factors. Despite a general trend of decreasing precipitation, the positive trend of annual runoff is due to a decrease in evaporation in the drainage areas, which depends both on the temperature regime of the research area and on the anthropogenic transformation of forest vegetation under logging impact. In spite of the considerable variability of annual river flow, trends in runoff coefficients for study rivers vary slightly, indicating the relative stability in water availability. This is due to cumulative effect of anthropogenic transformation of forest vegetation in the drainage areas, i.e. new felling, regeneration on logging sites and creating forest crops. Obtained results show that at the regional level in conditions of anthropogenic pressure on the forests in the drainage areas of medium and small rivers, the trends of climatic parameters, in particular precipitation, are offset by the forest harvesting and subsequent reforestation dynamics at clear cuts.

  13. Static converters power supply: transient regimes; Alimentation par convertisseurs statiques: regimes transitoires

    Energy Technology Data Exchange (ETDEWEB)

    Pasqualini, G. [Ecole Superieure d`Electricite (France)

    1997-08-01

    Direct current motors, asynchronous and variable speed synchronous motors are generally supplied with static converters. Speed variation is obtained by voltage variation in DC motors and by frequency variation in AC motors. In these conditions, these motors are running continuously in transient regimes: the DC motors current is not direct and the AC motors current is not sinusoidal. This situation leads to pulsing couples in the shaft line and to an increase of Joule effect losses. The aim of this paper is to present the methods of study of the electric motors functioning using the shape of the power voltages given by converters and mathematical models of these machines. The synchronous machines are rapidly described while the asynchronous machines are studied using Ku`s transformation instead of Park`s transformation for simplification. For each type of machine, calculation methods allow to determine their current, additional losses and couple characteristics. The transient regimes considered are those remaining when the motor is running at a constant speed and defined regime (supply voltages are periodical functions of time). These transient regimes are identically reproducing with a frequency which is a multiple of the converters supply frequency. Transient regimes due to functioning changes of the motor, such as resisting couple or power supply frequency variations, are not considered in this study. (J.S.) 9 refs.

  14. [Burden and health effects of shift work].

    Science.gov (United States)

    Heitmann, Jörg

    2010-10-01

    In Germany aprox. 15% of all employees have irregular or flexible working hours. Disturbed sleep and/or hypersomnia are direct consequences of shift work and therefore described as shift work disorder. Beyond this, shift work can also be associated with specific pathological disorders. There are individual differences in tolerance to shift work. Optimization of both shift schedules and sleep to "non-physiological" times of the day are measures to counteract the negative effects of shift work. There is still not enough evidence to recommend drugs for routine use in shift workers. © Georg Thieme Verlag Stuttgart · New York.

  15. Healthy food trends -- flaxseeds

    Science.gov (United States)

    ... seeds; Healthy food trends - linseeds; Healthy snacks - flaxseeds; Healthy diet - flaxseeds; Wellness - flaxseeds ... of nutrition and dietetics: dietary fatty acids for healthy adults. J Acad Nutr Diet . 2014;114(1):136-153. PMID: 24342605 www. ...

  16. Health Plans - Trend Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — This page contains several useful trend and competition indicators. Certain files will be updated monthly while others will be updated quarterly. The files are the...

  17. Healthy food trends - kale

    Science.gov (United States)

    Healthy food trends - borecole; Healthy snacks - kale; Weight loss - kale; Healthy diet - kale; Wellness - kale ... Kale is full of vitamins and minerals, including: Vitamin A Vitamin C Vitamin K If you take ...

  18. Dismantling technologies trends

    International Nuclear Information System (INIS)

    Devaux, P.

    2009-01-01

    In this work dismantling technologies trends realized by the CEA are reviewed. There following technologies are presented: Data acquisition from facilities; Scenario studies; Remote handling and carriers; Dismantling techniques; Decontamination.

  19. Terms of trade and exchange rate regimes in developing countries

    OpenAIRE

    Christian Broda

    2002-01-01

    Since Friedman (1953), an advantage often attributed to flexible exchange rate regimes over fixed regimes is their ability to insulate more effectively the economy against real shocks. I use a post-Bretton Woods sample (1973-96) of seventy-five developing countries to assess whether the responses of real GDP, real exchange rates, and prices to terms-of-trade shocks differ systematically across exchange rate regimes. I find that responses are significantly different across regimes in a way tha...

  20. Refrigeration. Two-Phase Flow. Flow Regimes and Pressure Drop

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature.......The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature....