High Density Preheating Effects on Q-ball Decays and MSSM Inflation

Non-perturbative preheating decay of post-inflationary condensates often results in a high density, low momenta, non-thermal gas. In the case where the non-perturbative classical evolution also leads to Q-balls, this effect shields them from instant dissociation, and may radically change the thermal history of the universe. For example, in a large class of inflationary scenarios, motivated by the MSSM and its embedding in string theory, the reheat temperature changes by a multiplicative factor of $10^{12}$.Comment: 4 page

SPECTRAL PROCEDURES ENHANCE THE ANALYSIS OF THREE AGRICULTURAL TIME SERIES

Many agricultural and environmental variables are influenced by cyclic processes that occur naturally. Consequently their time series often have cyclic behavior. This study develops time series models for three different phenomena: (1) a 60 year-long state annual average crop yield record, (2) a four year-long daily stream flow record with values aggregated to weekly averages, and (3) a half-hour long wind speed record sampled at 10 hertz with values aggregated to 0.5 min averages. Trend tests, simple high pass filtering, and spectral analysis on original and detrended and residual data series are used to guide model development. Next, as a means to provide insight for researchers, nonlinear regression procedures are used to develop models in the time domain. The models considered may have a large scale trend, low to high frequency cycles, and, if need be, an autoregressive (AR) error structure. Selected models for all three sets included a trend component. The model for yield has a linear trend in time and includes two high frequency cycles of 2.3 and 2.5 years. The model for stream flow has a complicated trend consisting of splined polynomials in the square root of time. Cycles include an annual and approximately 8, 6, and 3 month periods. Also an AR1 error structure is added. Results suggest the wind speed can be modeled as a superposition of damped and undamped oscillations. A zero order fractional Bessel function models the trend, here a damped oscillation with a period of 10.5 min. Smaller scale regular cycles of 6.6, 3.3 and 2.2 min are added along with an AR1 error structure. The use of time series methods instead of the inverse transform on selected frequencies allows for simultaneous estimation of all components. Moreover it opens the door to the use of a much broader class of functions to model the trend, to the use of other kinds of periodic functions to model the cycles, and to the incorporation of structure in the error term. This approach may provide useful insight and a methodological approach for several ongoing and some future studies at the National Soil Tilth Laboratory

On the binary nature of massive blue hypergiants: high-resolution X-ray spectroscopy suggests that Cyg OB2 12 is a colliding wind binary

The blue hypergiant Cyg OB2-12 (B3Ia+) is a representative member of the class of very massive stars in a poorly understood evolutionary stage. We obtained its high-resolution X-ray spectrum using Chandra observatory. PoWR model atmospheres were calculated to provide realistic wind opacities and to establish the wind density structure. We find that collisional de-excitation is the dominant mechanism de-populating the metastable upper levels of the forbidden lines of the He-like ions SiXIV and MgXII. Comparison between the model and observations reveals that X-ray emission is produced in a dense plasma, which could reside only at the photosphere or in a colliding wind zone between binary components. The observed X-ray spectra are well fitted by thermal plasma models, with average temperatures in excess of 10 MK. The wind speed in Cyg OB2-12 is not high enough to power such high temperatures, but the collision of two winds in a binary system can be sufficient. We used archival data to investigate the X-ray properties of other blue hypergiants. In general, stars of this class are not detected as X-rays sources. We suggest that our new Chandra observations of Cyg OB2-12 can be best explained if Cyg OB2-12 is a colliding wind binary possessing a late O-type companion. This makes Cyg OB2-12 only the second binary system among the 16 known Galactic hypergiants. This low binary fraction indicates that the blue hypergiants are likely products of massive binary evolution during which they either accreted a significant amount of mass or already merged with their companion.Comment: accepted to Ap

Width of percolation transition in complex networks

It is known that the critical probability for the percolation transition is not a sharp threshold, actually it is a region of non-zero width $\Delta p_c$ for systems of finite size. Here we present evidence that for complex networks $\Delta p_c \sim \frac{p_c}{l}$, where $l \sim N^{\nu_{opt}}$ is the average length of the percolation cluster, and $N$ is the number of nodes in the network. For Erd\H{o}s-R\'enyi (ER) graphs $\nu_{opt} = 1/3$, while for scale-free (SF) networks with a degree distribution $P(k) \sim k^{-\lambda}$ and $3<\lambda<4$, $\nu_{opt} = (\lambda-3)/(\lambda-1)$. We show analytically and numerically that the \textit{survivability} $S(p,l)$, which is the probability of a cluster to survive $l$ chemical shells at probability $p$, behaves near criticality as $S(p,l) = S(p_c,l) \cdot exp[(p-p_c)l/p_c]$. Thus for probabilities inside the region $|p-p_c| < p_c/l$ the behavior of the system is indistinguishable from that of the critical point

Volatility of Linear and Nonlinear Time Series

Previous studies indicate that nonlinear properties of Gaussian time series with long-range correlations, $u_i$, can be detected and quantified by studying the correlations in the magnitude series $|u_i|$, i.e., the ``volatility''. However, the origin for this empirical observation still remains unclear, and the exact relation between the correlations in $u_i$ and the correlations in $|u_i|$ is still unknown. Here we find analytical relations between the scaling exponent of linear series $u_i$ and its magnitude series $|u_i|$. Moreover, we find that nonlinear time series exhibit stronger (or the same) correlations in the magnitude time series compared to linear time series with the same two-point correlations. Based on these results we propose a simple model that generates multifractal time series by explicitly inserting long range correlations in the magnitude series; the nonlinear multifractal time series is generated by multiplying a long-range correlated time series (that represents the magnitude series) with uncorrelated time series [that represents the sign series $sgn(u_i)$]. Our results of magnitude series correlations may help to identify linear and nonlinear processes in experimental records.Comment: 7 pages, 5 figure

Study of fetomaternal arterial doppler parameters in early onset pre-eclampsia and its correlation with perinatal outcomes

Background: Development of pre-eclampsia (PE) at less than 34 weeks of gestation is known as early onset PE (EOPE) and is commonly associated with more severe adverse maternal and fetal outcomes. The purpose of this study was to study Doppler parameters of uterine, umbilical and fetal middle cerebral arteries exclusively in women with EOPE and its correlation with perinatal outcomes. This study was a hospital-based observational prospective study.Methods: 60 patient of early onset PE with singleton live pregnancy were included in the study and followed up. The results of sonographic and Doppler examination were analysed and correlated with perinatal outcomes.Results: Adverse perinatal outcomes were seen in 66.66% cases of early onset PE. To predict adverse perinatal outcomes, umbilical artery (Umb A) RI, PI were found to be most sensitive, cerebroplacental ratio (CPR) was most specific indicator with highest positive predictive value (PPV). Absent end diastolic flow /reverse end diastolic flow (AEDF/REDF) were ominous signs.Conclusions: Early onset PE is recently considered a more severe disease with different etiopathogenesis. Doppler study is the primary imaging modality for fetomaternal surveillance for follow up and prediction of perinatal outcome, thus allowing planning of timely management in early onset PE patients, as these patients are at higher risk of adverse perinatal outcomes

Light-Heavy Symmetry: Geometric Mass Hierarchy for Three Families

The Universal Seesaw pattern coupled with a Light$\leftrightarrow$Heavy symmetry principle leads to the Diophantine equation $\displaystyle N = \sum_{i=1}^Nn_i$, where $n_i\geq 0$ and distinct. Its unique non-trivial solution $(3=0+1+2)$ gives rise to the geometric mass hierarchy $m_W$, $m_W\epsilon$, $m_W\epsilon^2$ for $N=3$ fermion families. This is realized in a model where the hybrid (yet Up$\leftrightarrow$Down symmetric) quark mass relations $m_d m_t \approx m_c^2\leftrightarrow m_u m_b \approx m_s^2$ play a crucial role in expressing the CKM mixings in terms of simple mass ratios, notably $\sin\theta_C \approx {m_c\over m_b}$.Comment: 12 pages, no figures, Revtex fil