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Search Results: 1 - 10 of 23997 matches for " Jo Ridley "
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General Theory of Economics: CDR Supply Side Scientific Growth Law Unveiled  [PDF]
Dennis Ridley
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.815223
Abstract: The capitalism (C), democracy (D) and rule of law (R)CDR global invariant hypothesis was previously demonstrated for year 2014 cross country per capita real gross domestic product adjusted for purchasing power parity (G). Consistent with the principle of parsimony, the CDR index explained G with only these three variables. This paper re-estimates the model for the last 22 years of available data. The result is model parameters that are a set of global time invariant constants. These constants constitute the global time invariant CDR index defined by the vector inner (dot) product of the global constants and country C, D, R and C·D·R. This establishes the CDR global time invariant hypothesis. Exogenous and endogenous components of capital are decoupled to calculate and explain the values and roles of new ideas versus old capital stock. Based on the unitary entrepreneurship elasticity of G, the theoretical optimal reinvestment in capital stock is validated by empirical gross fixed capital formation. Together, these place economic growth on a scientific basis. Because of the absence of explicit definitions in the extant literature for concepts such as capitalist, capitalism, entrepreneurship and other consequential terminologies, they are clarified in concise nomenclature.
General Theory of Antithetic Time Series  [PDF]
Pierre Ngnepieba, Dennis Ridley
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.312197
Abstract: A generalized antithetic time series theory for exponentially derived antithetic random variables is developed. The correlation function between a generalized gamma distributed random variable and its pth exponent is derived. We prove that the correlation approaches minus one as the exponent approaches zero from the left and the shape parameter approaches infinity.
Conservation of Capital: Homeomorphic Mapping from Intangible Aggregate Macro-Economic CDR Space into Tangible Micro-Economic Production Spaces  [PDF]
Dennis Ridley, Pierre Ngnepieba
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.811138
Abstract: The parsimonious capitalism, democracy, rule of law (CDR) growth model is the first global time invariant cross country model. It is the first to incorporate aggregate exogenous and endogenous sources of capital into a model for converting capital to real gross domestic product adjusted for purchasing power parity. Aggregate capital is distributed to micro-economic units of production. This mapping is shown to be homeomorphic from intangible aggregate macro-economic CDR space into tangible micro-economic production spaces, such that under certain prescribed conditions capital is conserved.
Agreement between activPAL and ActiGraph for assessing children's sedentary time
Nicola D Ridgers, Jo Salmon, Kate Ridley, Eoin O'Connell, Lauren Arundell, Anna Timperio
International Journal of Behavioral Nutrition and Physical Activity , 2012, DOI: 10.1186/1479-5868-9-15
Abstract: Forty-eight children (54% boys) aged 8-12 years wore a waist-mounted AG and thigh-mounted aP for two consecutive school days (9-3:30 pm). AG data were analyzed using 17 cut-points between 50-850 counts·min-1 in 50 counts·min-1 increments to determine sedentary time during class-time, break time and school hours. Sitting and sitting plus standing time were obtained from the aP for these periods. Limits of agreement were computed to evaluate bias between AG50 to AG850 sedentary time and sitting and sitting plus standing time. Receiver Operator Characteristic (ROC) analyses identified AG cut-points that maximized sensitivity and specificity for sitting and sitting plus standing time.The smallest mean bias between aP sitting time and AG sedentary time was AG150 for class time (3.8 minutes), AG50 for break time (-0.8 minutes), and AG100 for school hours (-5.2 minutes). For sitting plus standing time, the smallest bias was observed for AG850. ROC analyses revealed an optimal cut-point of 96 counts·min-1 (AUC = 0.75) for sitting time, which had acceptable sensitivity (71.7%) and specificity (67.8%). No optimal cut-point was obtained for sitting plus standing (AUC = 0.51).Estimates of free-living sitting time in children during school hours can be obtained using an AG cut-point of 100 counts·min-1. Higher sedentary cut-points may capture both sitting and standing time.There is increasing interest in the effects of sedentary behaviors on children's and adults' health [1,2] largely due to emerging evidence that objectively-assessed sedentary time is associated with cardio-metabolic health [3-5]. The ActiGraph (AG) accelerometer has been commonly used in the objective assessment of sedentary time. However, there is considerable variability in the cut-points used to identify sedentary time using this accelerometer in child populations. AG sedentary time cut-points used in school-aged children and adolescents have included 100 counts·min-1 [6,7], 200 counts·min-1 [8], 500 counts
What initiates actin polymerization?
Anne Ridley
Genome Biology , 2000, DOI: 10.1186/gb-2000-1-1-reviews102
Abstract: A major breakthrough in analysing the regulation of actin polymerization has been the ability to initiate the process in vitro using purified proteins and a combination of biochemical fractionation and informed guesswork. Different laboratories have used either the bacteria Shigella and Listeria, the GTPase Cdc42, or micelles of the phospholipid phosphatidylinositol (4,5) bisphosphate (PIP2) to initiate actin polymerization in vitro. Amazingly, the cellular components required for each of these initiators to induce actin polymerization are mostly identical (Figure 1). In all cases, the Arp2/3 complex is the key central component that somehow brings together actin monomers to form a new nucleus for actin polymerization, but the precise mechanisms whereby each initiator recruits the Arp2/3 complex varies. The Arp2/3 complex can be activated in vitro by binding to the Wiskott-Aldrich syndrome protein WASP/N-WASP via the carboxy-terminal acidic region of these proteins (Tom Pollard, Salk Institute). Cdc42 can bind to full-length N-WASP and stimulate its ability to activate the Arp2/3 complex, thereby inducing actin polymerization. Shigella recruits N-WASP via its IcsA protein, whereas Listeria bypasses the requirement for WASP and binds to and activates the Arp2/3 complex directly through an acidic region of the Listeria ActA protein (Matt Welch, University of California Berkeley).Using a biochemical fractionation approach, Rajat Rohatgi and Marc Kirschner (Harvard Medical School) reported that Cdc42- and PIP2-induced actin polymerization in vitro requires a complex of proteins that includes N-WASP, the Arp2/3 complex, and an as yet unidentified 140kDa Cdc42-interacting protein. Polymerization can be initiated by adding purified N-WASP or the carboxy-terminal WA region of N-WASP to the other components (Figure 2). Interestingly, the amino-terminal WH1 domain of N-WASP,which has been reported to bind to PIP2, is not required for PIP2-induced actin polymerization. This im
The Rational Optimist: How Prosperity Evolves
Matt Ridley
Brock Education : a Journal of Educational Research and Practice , 2012,
Abstract: There is much debate about the state of the world. Matt Ridley argues in The Rational Optimist that we can solve problems such as economic crashes,population explosions, climate change and terrorism, of poverty, AIDS, depression and obesity. His trust of capitalism and progress is examined and challenged in this book review.
Intra-ocular acrylic lenses after cataract extraction
Ridley Harold
Bulletin of the World Health Organization , 2003,
Abstract:
A Role for Parasites in Stabilising the Fig-Pollinator Mutualism
Derek W. Dunn,Simon T. Segar,Jo Ridley,Ruth Chan,Ross H. Crozier,Douglas W. Yu,James M. Cook
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0060059
Abstract: Mutualisms are interspecific interactions in which both players benefit. Explaining their maintenance is problematic, because cheaters should outcompete cooperative conspecifics, leading to mutualism instability. Monoecious figs (Ficus) are pollinated by host-specific wasps (Agaonidae), whose larvae gall ovules in their “fruits” (syconia). Female pollinating wasps oviposit directly into Ficus ovules from inside the receptive syconium. Across Ficus species, there is a widely documented segregation of pollinator galls in inner ovules and seeds in outer ovules. This pattern suggests that wasps avoid, or are prevented from ovipositing into, outer ovules, and this results in mutualism stability. However, the mechanisms preventing wasps from exploiting outer ovules remain unknown. We report that in Ficus rubiginosa, offspring in outer ovules are vulnerable to attack by parasitic wasps that oviposit from outside the syconium. Parasitism risk decreases towards the centre of the syconium, where inner ovules provide enemy-free space for pollinator offspring. We suggest that the resulting gradient in offspring viability is likely to contribute to selection on pollinators to avoid outer ovules, and by forcing wasps to focus on a subset of ovules, reduces their galling rates. This previously unidentified mechanism may therefore contribute to mutualism persistence independent of additional factors that invoke plant defences against pollinator oviposition, or physiological constraints on pollinators that prevent oviposition in all available ovules.
A Role for Parasites in Stabilising the Fig-Pollinator Mutualism
Derek W Dunn,Simon T Segar,Jo Ridley,Ruth Chan,Ross H Crozier,Douglas W Yu,James M Cook
PLOS Biology , 2008, DOI: 10.1371/journal.pbio.0060059
Abstract: Mutualisms are interspecific interactions in which both players benefit. Explaining their maintenance is problematic, because cheaters should outcompete cooperative conspecifics, leading to mutualism instability. Monoecious figs (Ficus) are pollinated by host-specific wasps (Agaonidae), whose larvae gall ovules in their “fruits” (syconia). Female pollinating wasps oviposit directly into Ficus ovules from inside the receptive syconium. Across Ficus species, there is a widely documented segregation of pollinator galls in inner ovules and seeds in outer ovules. This pattern suggests that wasps avoid, or are prevented from ovipositing into, outer ovules, and this results in mutualism stability. However, the mechanisms preventing wasps from exploiting outer ovules remain unknown. We report that in Ficus rubiginosa, offspring in outer ovules are vulnerable to attack by parasitic wasps that oviposit from outside the syconium. Parasitism risk decreases towards the centre of the syconium, where inner ovules provide enemy-free space for pollinator offspring. We suggest that the resulting gradient in offspring viability is likely to contribute to selection on pollinators to avoid outer ovules, and by forcing wasps to focus on a subset of ovules, reduces their galling rates. This previously unidentified mechanism may therefore contribute to mutualism persistence independent of additional factors that invoke plant defences against pollinator oviposition, or physiological constraints on pollinators that prevent oviposition in all available ovules.
Alfvén wings at Earth's magnetosphere under strong interplanetary magnetic fields
A. J. Ridley
Annales Geophysicae (ANGEO) , 2007,
Abstract: A number of recent studies have shown that the upstream Mach number may play a significant role in the energy transfer between the solar wind and the magnetosphere. Magnetohydrodynamic (MHD) simulation results of the magnetosphere-ionosphere system are presented that show the transition from nominal solar wind and interplanetary magnetic field driving to extremely strong driving. One of the predominant features of the magnetosphere that becomes apparent during low Mach number conditions is the formation of Alfvén wings above and below the magnetosphere. Alfvén wing are cavities of low flow, and have been observed at Io and Ganymede, both of which reside in regions of sub-Alfvénic flow. It is shown that Alfvén wings exist even during nominal Mach number time periods – the wings fold over to form what has been classically viewed as the magnetotail. The regions of low flow within the Alfvén wing limit the electric field applied across the ionosphere, hence causing the ionospheric cross polar cap potential to be dependent upon the Mach number, and in turn, causing the saturation of the potential.
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