Statistical Eigenmode Transmission Over Jointly Correlated MIMO Channels

We investigate multiple-input multiple-output (MIMO) eigenmode transmission using statistical channel state information at the transmitter. We consider a general jointly correlated MIMO channel model, which does not require separable spatial correlations at the transmitter and receiver. For this model, we first derive a closed-form tight upper bound for the ergodic capacity, which reveals a simple and interesting relationship in terms of the matrix permanent of the eigenmode channel coupling matrix and embraces many existing results in the literature as special cases. Based on this closed-form and tractable upper bound expression, we then employ convex optimization techniques to develop low-complexity power allocation solutions involving only the channel statistics. Necessary and sufficient optimality conditions are derived, from which we develop an iterative water-filling algorithm with guaranteed convergence. Simulations demonstrate the tightness of the capacity upper bound and the near-optimal performance of the proposed low-complexity transmitter optimization approach.     

Study of the Effect of Strontium (Sr) on the Nucleation of Eutectic Silicon (Si) in High Purity Hypoeutectic Al-5Si Alloys

High purity Al-5Si (wt. %) master alloys containing different levels of Sr additions were manufactured in an arc melter under high vacuum. The alloys were melt-spun which resulted in the production of thin ribbons. The microstructure of the ribbons consisted of Al matrix and entrained eutectic droplets. The ribbons were subsequently investigated using differential scanning calorimetry (DSC) and conventional transmission electron microscopy (CTEM) to examine the effect of Sr on the droplet undercooling and nucleation of eutectic silicon. The results indicate that the addition of Sr increases the eutectic droplet nucleation undercooling (ΔT). This may be due to Sr poisoning of the AlP phase.     

Influence of calcium and phosphorus, lactose, and salt-to-moisture ratio on Cheddar cheese quality: changes in residual sugars and water-soluble organic acids during ripening

Cheddar cheese ripening involves the conversion of lactose to glucose and galactose or galactose-6-phosphate by starter and nonstarter lactic acid bacteria. Under ideal conditions (i.e., where bacteria grow under no stress of pH, water activity, and salt), these sugars are mainly converted to lactic acid. However, during ripening of cheese, survival and growth of bacteria occurs under the stressed condition of low pH, low water activity, and high salt content. This forces bacteria to use alternate biochemical pathways resulting in production of other organic acids. The objective of this study was to determine if the level and type of organic acids produced during ripening was influenced by calcium (Ca) and phosphorus (P), residual lactose, and salt-to-moisture ratio (S/M) of cheese. Eight cheeses with 2 levels of Ca and P (0.67 and 0.47% vs. 0.53 and 0.39%, respectively), lactose at pressing (2.4 vs. 0.78%), and S/M (6.4 vs. 4.8%) were manufactured. The cheeses were analyzed for organic acids (citric, orotic, pyruvic, lactic, formic, uric, acetic, propanoic, and butyric acids) and residual sugars (lactose, galactose) during 48 wk of ripening using an HPLC-based method. Different factors influenced changes in concentration of residual sugars and organic acids during ripening and are discussed in detail. Our results indicated that the largest decrease in lactose and the largest increase in lactic acid occurred between salting and d 1 of ripening. It was interesting to observe that although the lactose content in cheese was influenced by several factors (Ca and P, residual lactose, and S/M), the concentration of lactic acid was influenced only by S/M. More lactic acid was produced in low S/M treatments compared with high S/M treatments. Although surprising for Cheddar cheese, a substantial amount (0.2 to 0.4%) of galactose was observed throughout ripening in all treatments. Minor changes in the levels of citric, uric, butyric, and propanoic acids were observed during early ripening, whereas during later ripening, a substantial increase was observed. A gradual decrease in orotic acid and a gradual increase in pyruvic acid content of the cheeses were observed during 12 mo of ripening. In contrast, acetic acid did not show a particular trend, indicating its role as an intermediate in a biochemical pathway, rather than a final product.     

Maternal folate supply and sex influence gene‐specific DNA methylation in the fetal gut

Scope : Epidemiological evidence supports the developmental origins of health and disease hypothesis that developmental under/over‐nutrition increases adulthood disease risk. Epigenetic markings are one potential mechanism mediating these effects. Altered folate supply may influence methyl group availability for DNA methylation. We reported low folate supply in utero was associated with reduced global DNA methylation in the murine small intestine of adult offspring. We hypothesised that aberrant methylation would be observed during early development. Methods and results : Female C57BL/6J mice were fed diets containing 2 mg folic acid/kg or 0.4 mg folic acid/kg 4 wk before mating and during pregnancy. At 17.5 day gestation, gene methylation in fetal gut was analysed by Pyrosequencing^®. Low folate reduced overall methylation of Slc394a by 3.4% (p=0.038) but did not affect Esr1 or Igf2 differentially methylated region (DMR) 1. There were sex‐specific differences in Slc394a and Esr1 methylation (2.4% higher in females (p=0.002); 4% higher in males (p=0.0014), respectively). Conclusion : This is the first study reporting causal effects of maternal folate depletion on gene‐specific methylation in fetal gut. These observations support reports that altered methyl donor intake during development affects DNA methylation in the offspring. The consequences of epigenetic changes for health throughout the life course remain to be investigated.     

Global sensitivity analysis of wind turbine power output

The dynamics of wind turbine behavior are complex and a critical area of study for the wind industry. Identification of factors that cause changes in turbine performance can sometimes prove to be challenging, whereas other times, it can be intuitive. The quantification of the effect that these factors have is valuable for making improvements to both power performance and turbine health. In commercial farms, large quantities of meteorological and performance data are commonly collected to monitor daily operations. These data can also be used to analyze the relationship between each parameter in order to better understand the interactions that occur and the information contained within these signals. In this global sensitivity analysis, a neural network is used to model select wind turbine supervisory control and data acquisition system parameters for an array of turbines from a commercial wind farm that exhibit signs of wake interaction. An extended Fourier amplitude sensitivity test is then performed for 2 years of 10‐min averaged data. The study examines the primary and combined sensitivities of power output to each selected parameter for two turbines in the array. The primary sensitivities correspond to single parameter interactions, whereas combined sensitivities account for interactions between multiple parameters simultaneously. Highly influential parameters such as wind speed and rotor rotation frequency produce expected results; the extended Fourier amplitude sensitivity test method proved effective at quantifying the sensitivity of a wide range of more subtle inputs. These include blade pitch, yaw position, main bearing and ambient temperatures as well as wind speed and yaw position standard deviation. The technique holds promise for application in full‐scale wake studies where it might be used to determine the benefits of emerging power optimization strategies such as active wake management. The field of structural health monitoring can also benefit from this method. Copyright © 2013 John Wiley & Sons, Ltd.     

Representing primary electrophoretic data in the 1/time domain: comparison to representations in the time domain

A plot of absorbance vs 1/time (the "1/time domain") is a more useful representation of the primary data in capillary electrophoresis than traditional plots of absorbance vs time (the "time domain") in a wide set of circumstances, especially when comparing electropherograms in which the rate of electroosmotic flow is not precisely the same. The quantity that is of fundamental interest in capillary electrophoresis (CE) is the electrophoretic mobility of an analyte. The electrophoretic mobility of a species is nonlinearly proportional to time and, therefore, not linearly represented in the time domain: that is, the distance between two peaks along the time axis is not linearly related to the difference in their electrophoretic mobilities. In contrast, the electrophoretic mobility is linearly proportional to 1/time, and the distance between two peaks along the 1/time axis is linearly related to the difference in electrophoretic mobilities. Plots in the 1/time domain are similar to the familiar plots in the time domain (each analyte is represented by a peak, and the order of peaks corresponds to the order in which these analytes reach the detector), but the spacing between the peaks corresponds linearly to differences in mobility. This article derives this useful, visually appealing, and broadly applicable plotting strategy and illustrates common situations in which these plots are more useful than plots in the time domain.     

Prognostic relevance of urokinase plasminogen activator detection in micrometastatic cells in the bone marrow of patients with primary breast cancer

The "attentional model" of time estimation assumes that temporal judgments depend on the amount of attention allocated to the temporal processor (the timer). One of the main predictions of this model is that an interval will be judged shorter when attention is not allocated to the temporal parameters of the task. Previous studies combining temporal and nontemporal tasks (dual-task method) have suggested that the time spent processing the target duration might be a key factor. The less time devoted by the subject to the temporal task, the shorter the judged duration. In the two experiments presented here, subjects were asked to judge both the duration of a visual stimulus and an increment in intensity occurring at any time during this stimulus. In the second experiment, trials without intensity increments were added. The main result is that the judged duration was shorter when the increment occurred later in the stimulus or did not occur. In those cases, subjects had been expecting increment occurrence during most part of the stimulus and thus had focused for a shorter time on stimulus duration. We propose that attention shifts related to expectancy and to detection of the increment reduce subjective duration.     

Equilibrium Parameters for the Sorption of Copper,Cadmium and Zinc Ions onto Peat

This paper details a study into the sorption of three divalent metal ions—namely cadmium, copper and zinc—onto peat, in single component, binary and ternary systems. The Langmuir Freundlich and Redlich–Peterson equilibrium isotherms for each metal ion in each system have been determined and correlated. The Langmuir isotherms have been found to have the highest regression correlation coefficients. © 1997 SCI.     

Pitfalls in Protection: How Theory Can Enrich Our Understanding of Regulatory Compliance Problems in Planning Practice

This paper responds to demands for greater academic investigation into environmental protection, specifically the practical and structural problems which underpin regulatory compliance in the planning system. It critiques traditional theories of regulation and answers calls for the development of a thematic lens to facilitate the scrutiny of not only operational practice, but also the broader institutional regime. An empirical investigation builds upon the construct of really responsive regulation to study planning control and it becomes apparent that not only are there significant procedural planning difficulties facing regulatory compliance, but also that a much wider raft of issues must be considered if the complex equation is to be solved. The findings demonstrate how theory can be applied to enrich our rudimentary understanding of deep-seated problems and foster insights into areas of structural importance which are relevant to both planning and the wider regulatory arena.