Simulation of Northeast U.S. Extreme Precipitation and Its Associated Circulation by CMIP5 Models

Historical simulations from 14 models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5) are evaluated for their ability to reproduce observed precipitation in the northeastern United States and its associated circulation, with particular emphasis on extreme (top 1%) precipitation. The models are compared to observations in terms of the spatial variations of extreme precipitation, seasonal cycles of precipitation and extreme precipitation frequency and intensity, and extreme precipitation circulation regimes. The circulation regimes are identified using k-means clustering of 500-hPa geopotential heights on extreme precipitation days, in both observations and in the models. While all models capture an observed northwest-to-southeast gradient of precipitation intensity (reflected in the top 1% threshold), there are substantial differences from observations in the magnitude of the gradient. These differences tend to be more substantial for lower-resolution models. However, regardless of resolution, and despite a bias toward too-frequent precipitation, many of the models capture the seasonality of observed daily precipitation intensity, and the approximate magnitude and seasonality of observed extreme precipitation intensity. Many of the simulated extreme precipitation circulation patterns are visually similar to the set of observed patterns. However, the location and magnitude of specific troughs and ridges within the patterns, as well as the seasonality of the patterns, may differ substantially from the observed corresponding patterns. A series of metrics is developed based on the observed regional characteristics to facilitate comparison between models.

Magnitudes Count in Math Education – an Interdisciplinary View

How children learn basic skills such as discriminating between different quantities and counting? According to the dominant Approximate Number System (ANS) theory,humans are born with the ability to discriminate between discrete quantities (i.e.,numbers). Accordingly, early math curriculum should focus on discrete quantities. This theory guides many early-math curricula worldwide. We provide a review of empirical evidence challenging the ANS theory and introduced a more recent theoretical framework, the Approximate Magnitude System (AMS). This theory suggests that continuous magnitudes (such as area, density, volume, etc.) are more intuitive and acquired earlier then the ability to understand numbers. Using examples from early math education practices, we emphasize and demonstrate the potential benefits of taking the AMS approach and using magnitudes as a scaffolding for understanding numbers and more complex math concepts. Insights gained from studies that combines both cognitive psychology and educational research, with the active participation and contribution of early-math teachers, may be of assistance to both cognitive psychologists, interested in how math abilities develop, and to educators, looking to improve math curriculum. We hope that this article will inspire others to consider research in this direction and start a productive discussion on the role of continuous magnitudes in teaching math.

Genetic Developmental Disorders and Numerical Competence across the Lifespan

Due to their frequent uneven cognitive profiles, genetic developmental disorders allow researchers to investigate which numerical sub-system of those present in typically developing infants best predicts subsequent numerical abilities. More importantly, they can provide evidence of which other cognitive abilities outside number are necessary for the successful development of these numerical sub-systems. We discuss evidence from cross-syndrome comparisons of adults, adolescents, children, and infants with Williams syndrome and those with Down syndrome to show that the approximate magnitude sub-system is crucial for later number development. In addition, we show that specific problems outside the number domain, and within basic-level visual and attention systems contribute to an explanation of the difficulties and proficiencies observed within each genetic disorder. Finally, we argue that a truly developmental approach is critical when using the cross-syndrome design in order to reveal subtle differences that impact over time on the development of cognitive abilities.

Asteroseismology with SuperWASP

The highly successful SuperWASP planetary transit finding programme has surveyed a large fraction of both the northern and southern skies. There now exists in its archive over 420 billion photometric measurements for more than 31 million stars. SuperWASP provides good quality photometry with a precision exceeding 1% per observation in the approximate magnitude range 9 < V < 12. The archive enables long-baseline, high-cadence studies of stellar variability to be undertaken. An overview of the SuperWASP project is presented, along with results which demonstrate the survey's asteroseismic capabilities.

Ratio Abstraction by 6-Month-Old Infants

Human infants appear to be capable of the rudimentary mathematical operations of addition, subtraction, and ordering. To determine whether infants are capable of extracting ratios, we presented 6-month-old infants with multiple examples of a single ratio. After repeated presentations of this ratio, the infants were presented with new examples of a new ratio, as well as new examples of the previously habituated ratio. Infants were able to successfully discriminate two ratios that differed by a factor of 2, but failed to detect the difference between two numerical ratios that differed by a factor of 1.5. We conclude that infants can extract a common ratio across test scenes and use this information while examining new displays. The results support an approximate magnitude-estimation system, which has also been found in animals and human adults.

Microearthquakes at Yucca Mountain, Nevada

We operated a microearthquake array in the neighborhood of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. The array consists of four high-gain (up to 34 million), narrow band (25 Hz) telemetered stations. Based on approximate magnitude calibration of the array we expect during quiet periods, for distances less than 15 km, complete recording of events at Yucca Mt. for M ≧ −1. We have operated the four stations for 12-hour periods overnight between August and October 1990 and intermittently afterward, until April 1991, when we began more or less continuous operation. The pattern of microearthquake activity confirms the existence of a zone of seismic quiescence in the vicinity of proposed repository. We recorded only about 10 events with S-P times of less than 3 sec (D &lt; 24 km). Most events had S-P times between 3 and 6.5 sec, consistent with the higher seismic activity at distances between 24 and 52 km observed by Rogers et al. (1987) and Gomberg (1991). Oliver et al. (1966) found, contrary to what has been observed by us for Yucca Mountain, that in seismically active areas most of the events had S-P times of less than 3 sec. We confirmed this expectation for four microearthquake stations near Mammoth Lakes, where we observed microearthquake rates of over 100 per day, most with S-P times of less than 3 sec. Extrapolation of seismicity data from the Southern Great Basin Seismic Network confirms the low microearthquake activity in the immediate vicinity of Yucca Mountain.

Deviations from Michaelis–Menten kinetics. Computation of the probabilities of obtaining complex curves from simple kinetic schemes

1. It is possible to calculate the intrinsic probability associated with any curve shape that is allowed for rational functions of given degree when the coefficients are independent or dependent random variables with known probability distributions. 2. Computations of such probabilities are described when the coefficients of the rational function are generated according to several probability distribution functions and in particular when rate constants are varied randomly for several simple model mechanisms. 3. It is concluded that each molecular mechanism is associated with a specific set of curve-shape probabilities, and this could be of value in discriminating between model mechanisms. 4. It is shown how a computer program can be used to estimate the probability of new complexities such as extra inflexions and turning points as the degree of rate equations increases. 5. The probability of 3 : 3 rate equations giving 2 : 2 curve shapes is discussed for unrestricted coefficients and also for the substrate-modifier mechanisms. 6. The probability associated with the numerical values of coefficients in rate equations is also calculated for this mechanism, and a possible method for determining the approximate magnitude of product-release steps is given. 7. The computer programs used in the computations have been deposited as Supplement SUP 50113 (21 pages) with the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem, J. (1978) 169, 5.

Servo control of end-tidal CO2 in paralyzed animals

We are reporting an electronic circuit which uses the peak end-tidal CO2 signal from a rapid infrared CO2 analyzer to vary the motor rate of a fixed volume respirator. It contains variable gain and a lag compensation network which permits critical damping to prevent oscillation. The CO2 analyzer, circuitry, and respirator are connected in a closed-loop servo system that allows automatic control of the CO2 level. The system's gain and performance are such that it can accommodate large changes of CO2 return to the lungs with no more than +/- 0.5 Torr carbon dioxide pressure (PCO2) error signal. It has proved useful in experiments on neural respiratory control in paralyzed animals where it is desired to keep PCO2 constant despite changes in cardiac output and venous and CO2 return to the lungs, and to monitor the approximate magnitude of these changes.