Evading Lyth bound in models of quintessential inflation

Quintessential inflation refers to an attempt to unify inflation and late-time cosmic acceleration using a single scalar field. In this letter we consider two different classes of quintessential inflation, one of which is based upon a Lagrangian with non-canonical kinetic term $k^2(\phi)\partial^\mu \phi \partial_\mu \phi$ and a steep exponential potential while the second class uses the concept of steep brane world inflation. We show that in both cases the Lyth bound can be evaded, despite the large tensor-to-scalar ratio of perturbations. The post-inflationary dynamics is consistent with nucleosynthesis constraint in these cases.Comment: 6 Latex pages, no figures, reference updated and typos corrected, To appear in PL

Improving k-nn search and subspace clustering based on local intrinsic dimensionality

In several novel applications such as multimedia and recommender systems, data is often represented as object feature vectors in high-dimensional spaces. The high-dimensional data is always a challenge for state-of-the-art algorithms, because of the so-called curse of dimensionality . As the dimensionality increases, the discriminative ability of similarity measures diminishes to the point where many data analysis algorithms, such as similarity search and clustering, that depend on them lose their effectiveness. One way to handle this challenge is by selecting the most important features, which is essential for providing compact object representations as well as improving the overall search and clustering performance. Having compact feature vectors can further reduce the storage space and the computational complexity of search and learning tasks. Support-Weighted Intrinsic Dimensionality (support-weighted ID) is a new promising feature selection criterion that estimates the contribution of each feature to the overall intrinsic dimensionality. Support-weighted ID identifies relevant features locally for each object, and penalizes those features that have locally lower discriminative power as well as higher density. In fact, support-weighted ID measures the ability of each feature to locally discriminate between objects in the dataset. Based on support-weighted ID, this dissertation introduces three main research contributions: First, this dissertation proposes NNWID-Descent, a similarity graph construction method that utilizes the support-weighted ID criterion to identify and retain relevant features locally for each object and enhance the overall graph quality. Second, with the aim to improve the accuracy and performance of cluster analysis, this dissertation introduces k-LIDoids, a subspace clustering algorithm that extends the utility of support-weighted ID within a clustering framework in order to gradually select the subset of informative and important features per cluster. k-LIDoids is able to construct clusters together with finding a low dimensional subspace for each cluster. Finally, using the compact object and cluster representations from NNWID-Descent and k-LIDoids, this dissertation defines LID-Fingerprint, a new binary fingerprinting and multi-level indexing framework for the high-dimensional data. LID-Fingerprint can be used for hiding the information as a way of preventing passive adversaries as well as providing an efficient and secure similarity search and retrieval for the data stored on the cloud. When compared to other state-of-the-art algorithms, the good practical performance provides an evidence for the effectiveness of the proposed algorithms for the data in high-dimensional spaces

Characterizing Avr genes of Leptosphaeria maculans and resistance responses among Canadian canola cultivars in western Canada

Blackleg of canola, caused by Leptosphaeria maculans (Desmaz.) Ces. & de Not, is a serious concern in western Canada. The disease had been managed successfully since 1990s with use of resistant cultivars and extended crop rotations until recent years when both blackleg incidence and severity increased noticeably. This may be attributed to changes in the pathogen population that erodes the resistance of canola cultivars. The resistance associated with Canadian canola (Brassica napus L.) cultivars (CCCs) in Canada is not clearly understood. The current study was conducted to investigate the race structure of L. maculans in commercial canola fields and determine its role in blackleg incidence and severity. In addition, resistance (R) genes in representative CCCs were characterized to understand their role in blackleg control against the current population of L. maculans. A total of 372 L. maculans isolates collected from 16 canola fields with different levels of blackleg severity in 2012 and 2013 were analysed for the presence or absence of particular avirulence (Avr) alleles by inoculating 12 lines of a host differential set with known R genes. The results indicated that the alleles AvrLm1, AvrLm3, AvrLm9 and AvrLep2 were at very low or undetectable levels in these fields, while AvrLm2, AvrLm4, AvrLm6 and AvrLm7 were generally common. Since only the R genes Rlm1 and Rlm3 are found commonly in CCCs, this result indicates that most of our cultivars are no longer effective against the current pathogen population on the prairies.Variation in Avr gene frequency was observed, depending on the cultivar, field or region studied, but these differences alone appeared insufficient to explain the variability in blackleg severity in these fields, and the erosion of Rlm1 and Rlm3 would unlikely be the primary cause of isolated blackleg outbreaks for most of the fields investigated

Synthesis and Liquid Crystalline Studies of 2,4-bis(4'-n-nonyloxybenzoyloxy)benzylidene-4''-n-alkoxyaniline

In this paper, a series of new Schiff-bases: 2,4-bis(4’‑n‑nonyloxy -benzoyloxy)benzylidene-4’’-n-alkyloxyaniline (DC9An) were synthesized. The characterization of compounds was achieved through using (ultra violet, infrared, 1H-nuclear magnetic resonance) measurements. This series comprises 10 members differ by the length of n-alkoxy chain (i.e., OCnH2n+1, n=1-10). Their liquid crystalline properties were studied using differential scanning calorimetry and polarizing optical microscopy. The lower series such as n=1-3 are purely nematogenic liquid crystals, but the other means (n=4-7) have nematic and smectic phases (SmC and SmA). The higher members (n=8-10) are purely smectogenic liquid crystals