Unusual Phase Reversal of Superhumps in ER Ursae Majoris

We studied the evolution of superhumps in the peculiar SU UMa-type dwarf nova, ER UMa. Contrary to the canonical picture of the SU UMa-type superhump phenomena, the superhumps of ER UMa show an unexpected phase reversal during the very early stage (~5 d after the superoutburst maximum). We interpret that a sudden switch to so-called late superhumps occurs during the very early stage of a superoutburst. What had been believed to be (ordinary) superhumps during the superoutburst plateau of ER UMa were actually late superhumps. The implication of this discovery is briefly discussed.Comment: 4 pages, 5 figures, submitted to Publ. Astron. Soc. Japa

World Soybean Demand: An Elasticity Analysis and Long-Term Projections

Soybeans are one of the most valuable crops in the world and are characterized by their multi-purpose uses: food, feed, fuel and other industrial usages such as paint, inks, and plastics. Out of 183.9 million tons of world supply/demand of soybeans in 2001-03 year, about 10% of them were directly consumed as food (5.9%) or feed (3.8%) but 84.2% of them were crushed into soyoil and soymeal. Soyoil is mainly processed to vegetable oil for human consumption and recently used as a biodiesel feedstock. Soymeal is used not only as feed for livestock (especially for pork and poultry due to its low fiber level) and aquaculture, but also as a good source of protein for the human diet in a variety of forms in different cultures. This paper analyzes the relationship of the demand for soybeans with economy at country and international levels. We use the county level domestic demand quantities with GDP data and apply an error correction mechanism (ECM) to estimate the long-term elasticities of demand for soybeans in the market/economy. Using the estimated long-term elasticities, the demands for soybeans are projected through 2030.soybean demand, elasticity, error correction mechanism (ECM), projection, Agribusiness, Crop Production/Industries, Demand and Price Analysis, Marketing, C22, C53, Q11,

World Soybean Production: Area Harvested, Yield, and Long-Term Projections

Soybean, production, yield, land use, long-term projection, exponential smoothing with damped trend, Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Land Economics/Use, Q1,

China's Meat Consumption: An Income Elasticity Analysis and Long-Term Projections

Bennett's law, China, meat consumption, income elasticity, vector error correction model (VECM), projection, Agricultural and Food Policy, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, C22, Q11, Q13,

Immunization of networks with community structure

In this study, an efficient method to immunize modular networks (i.e., networks with community structure) is proposed. The immunization of networks aims at fragmenting networks into small parts with a small number of removed nodes. Its applications include prevention of epidemic spreading, intentional attacks on networks, and conservation of ecosystems. Although preferential immunization of hubs is efficient, good immunization strategies for modular networks have not been established. On the basis of an immunization strategy based on the eigenvector centrality, we develop an analytical framework for immunizing modular networks. To this end, we quantify the contribution of each node to the connectivity in a coarse-grained network among modules. We verify the effectiveness of the proposed method by applying it to model and real networks with modular structure.Comment: 3 figures, 1 tabl

Cohomological non-rigidity of generalized real Bott manifolds of height 2

We investigate when two generalized real Bott manifolds of height 2 have isomorphic cohomology rings with Z/2 coefficients and also when they are diffeomorphic. It turns out that cohomology rings with Z/2 coefficients do not distinguish those manifolds up to diffeomorphism in general. This gives a counterexample to the cohomological rigidity problem for real toric manifolds posed in \cite{ka-ma08}. We also prove that generalized real Bott manifolds of height 2 are diffeomorphic if they are homotopy equivalent

Immediate Effects of Cervical Spine Thrust Joint Manipulation on Gait Parameters in Individuals with Neck Pain

Purpose/Hypotheses: 1. To investigate for any change in gait parameters in individuals with neck pain while walking with different functional neck conditions immediately following cervical thrust joint manipulation (TJM) versus a sham intervention. 2. To investigate any association between Global Rating of Change (GROC) scores and gait parameters immediately following cervical thrust joint manipulation versus a sham intervention. The hypotheses were that, a) cervical TJM would have an immediate effect on gait parameters during walking with the neck in at least one of three conditions (neutral, flexion/extension and rotation) among individuals with neck pain; and b) higher scores on the GROC would be associated with improved gait parameters post-intervention. Subjects: Convenience sample of 40 individuals (30 female; mean age 24.5 ± 6.78 years) with neck pain. To qualify, subjects had to have a score \u3e0 on the question of pain intensity in the neck on the Neck Disability Index (NDI) questionnaire and have no contraindications or precautions for cervical TJM. Materials/Methods: Subjects walked on a Zeno Walkway under the following conditions: 1) head in neutral; 2) head rotating from side-to-side, and 3) head nodding up and down. After completing 30 practice trials (10 in each condition), pre-intervention trial 1 gait parameters were recorded for each of the three neck conditions in a randomized order. After a 5-minute rest period, pre-intervention trial 2 was conducted for each condition in same order as trial 1. Subjects then received one of two randomly assigned interventions: cervical spine TJM or active cervical rotation. Immediately after the intervention, the subject returned to the Zeno Walkway for the post-intervention trial 3 in each of the three conditions, in the same order as their previous trials. Gait parameters of average step length, stride length, stride width, velocity, and cadence were analyzed using a 2x2 repeated measures ANOVA (of trials 2 and 3), as well as independent and paired t-tests, to determine if there were any significant changes based on intervention when comparing TJM to sham groups. Results: The results of the 2x2 ANOVA revealed significant interactions between group and time on average gait velocity (p=0.008), step length (p=\u3c0.001), and stride length (p=0.009) when the head was in a neutral position. The TJM group experienced significant increases from pre to post-intervention as shown by paired samples t-test for average gait velocity (p=0.003), step length (p\u3c0.001), and stride length (p=0.008). The sham group however, experienced no significant change in gait velocity (p = 0.290), average step length (p = 0.299), and stride length (p = 0.292). There was also a significant decrease in the Numeric Pain Rating Scale (NPRS) (mean decrease of 1.25; p=0.003) and the group that received cervical TJM reported an improved perception of change demonstrated by an average increase in GROC score by 2.85 (p=0.001). Conclusions: Although our results demonstrate a statistically significant improvement in three gait parameters following TJM while walking with the neck in a neutral position, the improvements are not clinically significant. At this time, there is no evidence-based indication for the clinical use of cervical TJM to improve gait parameters in individuals with neck pain. Our findings cannot confirm clinical significance for reduction of neck pain with cervical TJM based on NDI, NPRS, or GROC questionnaires

Distribution of Mutual Information

The mutual information of two random variables i and j with joint probabilities t_ij is commonly used in learning Bayesian nets as well as in many other fields. The chances t_ij are usually estimated by the empirical sampling frequency n_ij/n leading to a point estimate I(n_ij/n) for the mutual information. To answer questions like "is I(n_ij/n) consistent with zero?" or "what is the probability that the true mutual information is much larger than the point estimate?" one has to go beyond the point estimate. In the Bayesian framework one can answer these questions by utilizing a (second order) prior distribution p(t) comprising prior information about t. From the prior p(t) one can compute the posterior p(t|n), from which the distribution p(I|n) of the mutual information can be calculated. We derive reliable and quickly computable approximations for p(I|n). We concentrate on the mean, variance, skewness, and kurtosis, and non-informative priors. For the mean we also give an exact expression. Numerical issues and the range of validity are discussed.Comment: 8 page

A novel magnetic resonance imaging postprocessing technique for the assessment of intervertebral disc degeneration-Correlation with histological grading in a rabbit disc degeneration model.

Introduction:Estimation of intervertebral disc degeneration on magnetic resonance imaging (MRI) is challenging. Qualitative schemes used in clinical practice correlate poorly with pain and quantitative techniques have not entered widespread clinical use. Methods:As part of a prior study, 25 New Zealand white rabbits underwent annular puncture to induce disc degeneration in 50 noncontiguous lumbar discs. At 16 weeks, the animals underwent multi-echo T2 MRI scanning and were euthanized. The discs were stained and examined histologically. Quantitative T2 relaxation maps were prepared using the nonlinear least squares method. Decay Variance maps were created using a novel technique of aggregating the deviation in the intensity of each echo signal from the expected intensity based on the previous rate of decay. Results:Decay Variance maps showed a clear and well demarcated nucleus pulposus with a consistent rate of decay (low Decay Variance) in healthy discs that showed progressively more variable decay (higher Decay Variance) with increasing degeneration. Decay Variance maps required significantly less time to generate (1.0 ± 0.0 second) compared with traditional T2 relaxometry maps (5 (±0.9) to 1788.9 (±116) seconds). Histology scores correlated strongly with Decay Variance scores (r = 0.82, P < .01) and weakly with T2 signal intensity (r = 0.32, P < .01) and quantitative T2 relaxometry (r = 0.39, P < .01). Decay Variance had superior sensitivity and specificity for the detection of degenerate discs when compared to T2 signal intensity or Quantitative T2 mapping. Conclusion:Our results show that using a multi-echo T2 MRI sequence, Decay Variance can quantitatively assess disc degeneration more accurately and with less image-processing time than quantitative T2 relaxometry in a rabbit disc puncture model. The technique is a viable candidate for quantitative assessment of disc degeneration on MRI scans. Further validation on human subjects is needed

Voter model with non-Poissonian interevent intervals

Recent analysis of social communications among humans has revealed that the interval between interactions for a pair of individuals and for an individual often follows a long-tail distribution. We investigate the effect of such a non-Poissonian nature of human behavior on dynamics of opinion formation. We use a variant of the voter model and numerically compare the time to consensus of all the voters with different distributions of interevent intervals and different networks. Compared with the exponential distribution of interevent intervals (i.e., the standard voter model), the power-law distribution of interevent intervals slows down consensus on the ring. This is because of the memory effect; in the power-law case, the expected time until the next update event on a link is large if the link has not had an update event for a long time. On the complete graph, the consensus time in the power-law case is close to that in the exponential case. Regular graphs bridge these two results such that the slowing down of the consensus in the power-law case as compared to the exponential case is less pronounced as the degree increases.Comment: 18 pages, 8 figure