1,019 research outputs found
Are Fruit and Vegetable Prices Non-linear Stationary? Evidence from Smooth Transition Autoregressive Models
Over the last decade, there has been a growing interest in investigating agricultural commodity prices. We apply two more powerful smooth transition autoregressive models of the non-linear unit-root test - namely, the ESTAR model of Kapetanios et al. [Journal of Econometrics (2003)] and the LSTAR model of Leybourne, et a . [Journal of Time Series Analysis (1998)] - with a view to investigating non-linear stationarity for the retail prices of 8 major kinds of fruit and 18 major kinds of vegetable in Taiwan. The empirical evidence clearly finds that the Kapetanios et al. model provides solid, substantive evidence in favor of a non-linear mean-reverting adjustment for the individual price of 4 kinds of fruit and 5 kinds of vegetable. However, when we employ the Leybourne et al. model, we find that any such similar evidence of non-linear stationarity is considerably weaker. Finally, compared with the traditional linear unit root tests, it is important to note here that, all in all, the non-linear unit root tests do indeed provide much more evidence of the stationarity, albeit to varying degrees. This paper offers some policy implications.Smooth transition autoregressive model; Non-linear stationary; Fruit price; Vegetable price; Taiwan
Size-dependent calcium carbonate precipitation induced microbiologically in aerobic granules
Calcium and ash accumulation in aerobic granules treating organic wastewater was investigated systematically in this study. It was found that ash content of granular sludge reached 43% at stable state of reactor operation with calcium carbonate precipitation as the main cause. Since granular sludge in the reactor at the steady state was the mixture of granules with different sizes, granules in the reactor on operation days 90, 120 and 150, respectively, were sorted into 10 categories by size to study the inorganic substances. It was found that calcium was selectively enriched in granules and the precipitation of calcium carbonate was just dependent on granule size instead of operation duration at the steady state. More calcium carbonate was precipitated in bigger aerobic granules, but both calcium and ash contents reached stable values when granule size was bigger than 700 ?m. Analysis by X-ray diffractometer disclosed that aragonite was the only polymorph of calcium carbonate detected in aerobic granules with size bigger than 300 ?m. Scanning electron microscope revealed clearly for the first time that bundles of needle shaped aragonite was embedded in extracellular polymeric substances of aerobic granules. A mechanism on calcium carbonate precipitation was proposed to deepen the understanding of biomineralization
Hierarchical structure and modules in the Escherichia coli transcriptional regulatory network revealed by a new top-down approach
BACKGROUND: Cellular functions are coordinately carried out by groups of genes forming functional modules. Identifying such modules in the transcriptional regulatory network (TRN) of organisms is important for understanding the structure and function of these fundamental cellular networks and essential for the emerging modular biology. So far, the global connectivity structure of TRN has not been well studied and consequently not applied for the identification of functional modules. Moreover, network motifs such as feed forward loop are recently proposed to be basic building blocks of TRN. However, their relationship to functional modules is not clear. RESULTS: In this work we proposed a top-down approach to identify modules in the TRN of E. coli. By studying the global connectivity structure of the regulatory network, we first revealed a five-layer hierarchical structure in which all the regulatory relationships are downward. Based on this regulatory hierarchy, we developed a new method to decompose the regulatory network into functional modules and to identify global regulators governing multiple modules. As a result, 10 global regulators and 39 modules were identified and shown to have well defined functions. We then investigated the distribution and composition of the two basic network motifs (feed forward loop and bi-fan motif) in the hierarchical structure of TRN. We found that most of these network motifs include global regulators, indicating that these motifs are not basic building blocks of modules since modules should not contain global regulators. CONCLUSION: The transcriptional regulatory network of E. coli possesses a multi-layer hierarchical modular structure without feedback regulation at transcription level. This hierarchical structure builds the basis for a new and simple decomposition method which is suitable for the identification of functional modules and global regulators in the transcriptional regulatory network of E. coli. Analysis of the distribution of feed forward loops and bi-fan motifs in the hierarchical structure suggests that these network motifs are not elementary building blocks of functional modules in the transcriptional regulatory network of E. coli
6-Butyl-5-(4-methoxyphenoxy)-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one
The asymmetric unit of the title compound, C21H21N5O3, consists of two geometrically similar molecules. The fused rings of the triazolo[4,5-d]pyrimidine system are nearly coplanar, making dihedral angels of 1.48 (18) and 1.34 (16)°, and the phenyl rings are twisted by 12.3 (1) and 8.7 (1)° with respect to the triazolopyrimidine plane. The ethyl groups of the n-butyl side chains are disordered over two sites in each of the independent molecules, the ratios of occupancies being 0.60:0.40 and 0.61:0.39
6-Isopropyl-3-phenyl-5-(p-tolyloxy)-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one: whole-molecule disorder
The title compound, C20H19N5O2, exhibits whole-molecule disorder the refined ratios of the two components being 0.57 (2):0.43 (2). In the major component, the essentially planar [maximum deviation 0.033 (17) Å] fused pyrimidine and triazole ring system forms a dihedral angle of 10.5 (3)° with the phenyl ring, while in the minor component of disorder this angle is 27.5 (5)°. The crystal structure is stabilized by π–π stacking interactions between symmetry-related triazole and pyrimidine rings, with centroid–centroid distances of 3.594 (10) Å
Absolute Stability of a Class of Nonlinear Singular Systems with Time Delay
This paper deals with the absolute stability for a class of nonlinear singular systems with time delay. By employing a new Lyapunov-Krasovskii functional with the idea of partitioning delay length, improved delay-dependent stability criteria are established. The resulting condition is formulated in terms of linear matrix inequalities (LMIs), which is easy to be verified by exiting LMI optimization algorithms. A numerical example is given to show the effectiveness of the proposed technique and its improvements over the existing results
Beyond Non-Orthogonal Multiple Access: New Role of Constructive Interference
In this paper, we introduce a novel framework of constructive non-orthogonal multiple access (NOMA) transmission, which provides the merit of interference utilization and breaks through the constructive interference (CI)’s limitation on multiuser (MU) access capability. With dedicated synthetic successive coding and hybrid MU access designs, a novel constructive NOMA (CNOMA) precoder is proposed, which is particularly suitable for the scenario where users have heterogeneous throughput requirements. Explicitly, it makes the composite interference always beneficial to the users having high throughput requirement, while accommodating another sets of users under their subscribed reception-quality requirement. Finally, a number of fundamental properties of the CNOMA design is revealed, such as the tradeoff between utilization of MU interference and improvement of MU access capability. Simulation demonstrates that the proposed CNOMA precoder significantly outperforms the classic CI and minimum-mean-square-error precoders in throughput performance, and meanwhile obtains high access capability close to classic NOMA designs
6-Butyl-5-(4-methylphenoxy)-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one
In the title compound, C21H21N5O2, the triazolopyrimidine ring system is essentially planar [maximum displacement = 0.021 (4) Å] and forms dihedral angles of 41.17 (9) and 67.99 (8)° with the phenyl and benzene rings, respectively. The n-butyl side chains is disordered over two positions with an ccupancy ratio of 0.77:0.23. An intramolecular C—H⋯O hydrogen-bonding interaction stabilizes the molecular conformation. In the crystal, molecules are linked by intermolecular C—H⋯O and C—H⋯N hydrogen bonds into a three-dimensional network. In addition, π–π stacking interactions involving the triazole and pyrimidine rings of adjacent molecules are observed, with centroid–centroid distances of 3.545 (1) Å
A network‐based variable selection approach for identification of modules and biomarker genes associated with end‐stage kidney disease
AimsIntervention for end‐stage kidney disease (ESKD), which is associated with adverse prognoses and major economic burdens, is challenging due to its complex pathogenesis. The study was performed to identify biomarker genes and molecular mechanisms for ESKD by bioinformatics approach.MethodsUsing the Gene Expression Omnibus dataset GSE37171, this study identified pathways and genomic biomarkers associated with ESKD via a multi‐stage knowledge discovery process, including identification of modules of genes by weighted gene co‐expression network analysis, discovery of important involved pathways by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses, selection of differentially expressed genes by the empirical Bayes method, and screening biomarker genes by the least absolute shrinkage and selection operator (Lasso) logistic regression. The results were validated using GSE70528, an independent testing dataset.ResultsThree clinically important gene modules associated with ESKD, were identified by weighted gene co‐expression network analysis. Within these modules, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed important biological pathways involved in ESKD, including transforming growth factor‐β and Wnt signalling, RNA‐splicing, autophagy and chromatin and histone modification. Furthermore, Lasso logistic regression was conducted to identify five final genes, namely, CNOT8, MST4, PPP2CB, PCSK7 and RBBP4 that are differentially expressed and associated with ESKD. The accuracy of the final model in distinguishing the ESKD cases and controls was 96.8% and 91.7% in the training and validation datasets, respectively.ConclusionNetwork‐based variable selection approaches can identify biological pathways and biomarker genes associated with ESKD. The findings may inform more in‐depth follow‐up research and effective therapy.SUMMARY AT A GLANCEThis gene–gene network analysis to identify genes associated with end‐stage renal disease is an important step, albeit early, towards the discovery of biomarkers using peripheral blood cells. The findings also provide insight on disease pathophysiology at the molecular level, and hence therapeutic targets for future research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162799/2/nep13655.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162799/1/nep13655_am.pd
Perancangan Sistem Otomatis Update pada Aplikasi Desktop Abios
Unlike web applications easier to update the latest version, desktop applications more difficult and must involve the user in doing so. It is caused by a desktop application is an application that is installed in the computer user. The purpose of this research is to design an automatic system updates on a desktop application, an example case: Application Binus International Operational Support (ABIOS). This research used literature study and system design. In desktop applications, often there is update the latest applications that are not known to the user who sometimes fatal and disrupt business operations. Generally, developer will inform the changes version to user that they can update the application. In an update of applications, should be done by the system automatically, not manually by users. Once in a while, the user background is not from computer base. After doing the research, it can be concluded that the system automatically updates the application has benefits to users in obtaining information regarding the latest version, and can assist in automatically update the latest application is based on computerization. For further development of this system is expected to operate on multi platforms and or mobile applications
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