A Quantitative Stability Analysis of the Solutions to the Carson-Cambi Equation

A quantitative stability analysis of the Carson-Cambi equation [(1 + ε cos t)(d²y/dt²) + py = 0] is carried through, using a new, effective approach. The results are compared with a recent perturbation analysis, and show that this should not be used for ε0.4. In the present analysis we go up to ε = 0.8, and, in fact, with less effort than the perturbation analysis involves. Detailed stability diagrams are presented.     

Stability, L1-gain analysis and asynchronous L1-gain control of uncertain discrete-time switched positive linear systems with dwell time

In this paper, the stability, L₁-gain analysis and asynchronous L₁-gain control problems of uncertain discrete-time switched positive linear systems (DSPLSs) with dwell time are investigated. First, several convex and non-convex conditions on dwell time stability of DSPLSs with interval and polytopic uncertainties are presented, and the relation between these conditions is revealed. Then, via a switched dwell-time-dependent co-positive Lyapunov functions (SDTLFs) approach, convex sufficient conditions on L₁-gain analysis and asynchronous L₁-gain control of DSPLSs with interval uncertainties are derived. Meanwhile, via the switched parameter-dwell-time-dependent co-positive Lyapunov functions (SPDTLFs) approach, the L₁-gain analysis and asynchronous L₁-gain controller design problems of DSPLSs with polytopic uncertainties are also solved. The stability and L₁-gain analysis results are given in terms of linear programming (LP). The controller design results are presented in terms of bilinear programming (BP), which can be solved with the help of iterative algorithm. At last, both numerical and practical examples are provided to show the effectiveness of the results.     

The goodness of fit and the distribution of particle sizes

In a previous paper (1), reasons were given why the usual graphical analysis of the distribution of particle sizes should be replaced by an algebraic analysis. In the present paper, this method is developed and explained. Most of the mathematical argument has been removed from the text and is given in several appendices. The method of analysis described is comparatively new in that it uses the Chi-Square Minimum Principle instead of the more familiar principle of least squares.By the results of this analysis, it is possible to characterize the size distribution in a photographic emulsion, in the simpler cases, by two numbers (parameters): The first, denoted by a, which is related to the time of growth of the crystals, and the second, denoted by b, which is inversely proportional to the velocity constant of the growth. The first parameter is subject to statistical fluctuations within an individual emulsion; the second should be constant for one type of emulsion as long as the physicochemical conditions of growth are not altered.This theory is confirmed by careful analysis of one sample of an emulsion, eight subsamples of which were measured by the observer. The results of the statistical analysis show that the parameter, b, is the same for the eight subsamples within the limits of the experimental error. The values of the parameter, a, show, however, differences in excess of those limits. This is due to the local fluctuations of the time of growth throughout the emulsion, mentioned above. Statistically, there is, therefore, heterogeneity in one of the population parameters. Therefore, the results from the eight subsamples should not be added together. This is usually done with the intention to increase the goodness of the fit, but actually decreases it.     

Factors affecting university-industry R&D projects: The importance of searching, screening and signalling

This paper presents an empirical analysis of the determinants of research cooperation between firms and Public research organisations (PROs) for a sample of innovating small and medium-sized enterprises (SMEs). The econometric analysis is based on the results of the KNOW survey carried out in seven EU countries during 2000. In contrast to earlier works that provide information about the importance of PROs’ research, we know the number of firm/PRO collaborative research and development (R&D) projects. This allows us to study the determinants of firm collaboration with PROs in terms of both the propensity of a firm to undertake R&D projects with a university (do they cooperate or not) and the extent of this collaboration (number of R&D projects). Two questions are addressed. Which firms cooperated with PROs? And what are the firm characteristics that might explain the number of R&D projects with PROs? The results of our analysis point to two major phenomena. First, the propensity to forge an agreement with an academic partner depends on the ‘absolute size’ of the industrial partner. Second the openness of firms to the external environment, as measured by their willingness to search, screen and signal, significantly affects the development of R&D projects with PROs. Our findings suggest that acquiring knowledge through the screening of publications and involvement in public policies positively affects the probability of signing an agreement with a PRO, but not the number of R&D projects developed. In fact, firms that outsource research and development, and patent to protect innovation and to signal competencies show higher levels of collaboration.     

On the geometry of the smallest circle enclosing a finite set of points

A number of numerical codes have been written for the problem of finding the circle of smallest radius in the Euclidean plane that encloses a finite set P of points, but these do not give much insight into the geometry of this circle. We investigate geometric properties of the minimal circle that may be useful in the theoretical analysis of applications. We show that a circle C enclosing P is minimal if and only if it is rigid in the sense that it cannot be translated while still enclosing P. We show that the center of the minimal circle is in the convex hull of P. We use this rigidity result and an analysis of the case of three points to find sharp estimates on the diameter of the minimal circle in terms of the diameter of P.     

On the statistical analysis of Feigenbaum constants

We present statistical analysis of blocks in the binary expansions of Feigenbaum constants α and δ for the logistic map. The analysis is carried out on both 1016 and 3400 bit expansions. A χ² test is applied for lumping data and a serial test is applied on gliding data. Contrary to a previous research by Karamanos and Kotsireas, our test results did not indicate any evidence to reject randomness of these constants. Additional 25 randomness tests also support the conjecture of randomness of these constants having transcendental character.     

Proteolytic activity of recombinant DegP from Chromohalobacter salexigens BKL5

BackgroundDegP is a serine protease that specifically cleaves and refolds unfolding proteins in the periplasmic space of the cells. To date, there is no information regarding DegP from halophilic bacteria. Chromohalobacter salexigens BKL5 is a moderately halophilic bacterium that has the ability to grow in a media containing more than 15% salt. Therefore, the objectives of this work were to clone and overexpress DegP-encoding gene from C. salexigens BKL5 and characterize its biochemical properties.ResultsDegP-encoding gene was overexpressed in Escherichia coli BL21(DE3) CodonPlus in an active form. SDS-PAGE analysis showed that the molecular weight of the recombinant DegP was 45 kDa. Size-exclusion chromatography analysis suggested that recombinant DegP was present in two multimeric states, hexameric and dodecameric, with molecular weights of 297.9 and 579.12 kDa, respectively. Both conformations were enzymatically active when casein was used as substrate for enzymatic assay. Circular dichroism analysis showed that recombinant DegP was composed of 0.21–0.29 helical content, which was comparable to the helical content in the crystal structure of E. coli DegP. The basic/acidic residue ratio of recombinant DegP was 0.56, which was slightly higher than that of DegP from extreme halophiles (average, 0.45) but significantly lower than that of DegP from nonhalophiles (average, 0.94).ConclusionsRecombinant DegP from C. salexigens BKL5 showed proteolytic activity when β-casein was used as a substrate. In silico analysis indicated that recombinant DegP had characteristics similar to those of halophilic proteins depending on its amino acid composition.     

A new set of orthogonal functions and its application to the analysis of dynamic systems

The present work proposes a complementary pair of orthogonal triangular function (TF) sets derived from the well-known block pulse function (BPF) set. The operational matrices for integration in TF domain have been computed and their relation with the BPF domain integral operational matrix is shown. It has been established with illustration that the TF domain technique is more accurate than the BPF domain technique as far as integration is concerned, and it provides with a piecewise linear solution.As a further study, the newly proposed sets have been applied to the analysis of dynamic systems to prove the fact that it introduces less mean integral squared error (MISE) than the staircase solution obtained from BPF domain analysis, without any extra computational burden. Finally, a detailed study of the representational error has been made to estimate the upper bound of the MISE for the TF approximation of a function f(t) of Lebesgue measure.     

Association of CETP and LIPC Gene Polymorphisms with HDL and LDL Sub-fraction Levels in a Group of Indian Subjects: A Cross-Sectional Study

There is an increasing interest to understand the molecular basis of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) subfractions and their association with coronary artery disease (CAD). The formation of these subfractions is greatly influenced by hepatic lipase (HL) and cholesteryl ester transfer protein (CETP) enzymes. To identify genetic markers influencing LDL and HDL subfractions and their role in CAD we performed a case–control genetic association study on 117 healthy controls and 119 angiographically verified CAD patients. Biochemical analysis was performed using standard assays. HDL-C and LDL-C subfractions were estimated using precipitation methods. Genotyping of C-514T (rs1800588) in the LIPC gene for HL and I405V (rs5882) in the CETP gene was done using PCR-based restriction enzyme analysis and sequencing. Both the polymorphisms were not associated with CAD. The C-514T was associated with increased HDL₃-C levels in controls (P = 0.049). The I405V polymorphism was found to be associated with low levels of small dense, LDL (P = 0.038). A multiple regression analysis showed that the effects were dependent on gender and triglyceride levels. We conclude that these polymorphisms are not associated with CAD but are important determinants of HDL-C and small dense LDL particles in our population.     

Stability and dissipative analysis for a class of stochastic system with time-delay

This paper deals with the stability and dissipative problem of a class of stochastic hybrid system. The system under study involves Markovian jump, impulsive effects and time delay, which are often encountered in practice and are the sources of instability. Our attention is focused on analysis of whether the stochastic hybrid system with time-delay is stochastically asymptotically stable and strictly (Q, S, R) dissipative. By introducing an extra artificial time instance, the equivalent system is obtained and the sufficient conditions are derived by using linear matrix inequality (LMI) techniques. The main results of this paper unify the existing results on H_∞ control.     

Assessment of somaclonal variation in somatic embryo-derived plants of yacon [Smallanthus sonchifolius (Poepp. and Endl.) H. Robinson] using inter simple sequence repeat analysis and flow cytometry

BackgroundYacon (Smallanthus sonchifolius) is a root crop native to the Andean region. Low sexual reproductive capacity is a major constraint facing the genetic breeding of this crop. Biotechnological techniques offer alternative ways to widen genetic variability. We investigated somaclonal variation in regenerants of yacon derived from in vitro somatic embryogenesis using simple sequence repeat (ISSR) analysis and flow cytometry.ResultsTwenty tested ISSR primers provided a total of 7848 bands in 60 in vitro regenerants and control plant. The number of bands for each primer varied from 3 to 10, and an average of 6.95 bands was obtained per ISSR primer. Eight primers were polymorphic and generated 10 polymorphic bands with 7.19% mean polymorphism. ISSR analysis revealed genetic variability in 6 plants under study. These regenerants had Jaccard's distances 0.104, 0.020, 0.040, 0.106, 0.163 and 0.040. Flow cytometric analysis did not reveal changes of relative nuclear DNA content in regenerants suggesting that the plants obtained via somatic embryogenesis had maintained stable octoploid levels.ConclusionsOur findings show that indirect somatic embryogenesis could be used in yacon improvement to widen genetic variability, especially when low sexual reproductive capacity hinders classical ways of breeding.     

Identification and characterization of profilin gene family in rice

BackgroundProfilin proteins (PRFs) are small (12–15 kD) actin-binding protein, which play a significant role in cytoskeleton dynamics and plant development via regulating actin polymerization. Profilins have been well documented in Arabidopsis, Zea mays L. as well as Phaseolus vulgaris, however no such fully characterization of rice (Oryza sativa L.) profilin gene family has been reported thus far.ResultIn the present study, a comprehensive genome-wide analysis of rice PRF genes was completed and three members were identified. OsPRF1 and OsPRF2 shared 98.5% similarity (6 nucleotide divergence), but the deduced amino acid sequences of OsPRF1 and OsPRF2 are fully identical. In contrast, the OsPRF3 presents relatively lower similarity with OsPRF1 and OsPRF2. Phylogenetic analysis also support that OsPRF1 has a closer relationship with OsPRF2. Expression pattern analysis revealed the differential expression of OsPRFs in tissues of mature plant, which suggested the potential spatial functional specificity for rice profilin genes. Subcellular localization analysis revealed the OsPRFs were localized in cytoplasm and nucleus and all of them could bind actin monomers. Furthermore, abiotic stresses and hormones treatments assay indicated that the three OsPRF genes could be differentially regulated, suggesting that OsPRF genes might participate in different stress processes in rice.ConclusionsTaken together, our study provides a comprehensive analysis of the OsPRF gene family and will provide a basis for further studies on their roles in rice development and in response to abiotic stresses.How to cite: Zhang Y, Dong G, Wu L, et al. Identification and characterization of profilin gene family in rice. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.08.004.     

A quantitative study of isobaric equilibrium and gravity anomalies in the hawaiian islands

The deformation of a strong elastic lithosphere supported by an underlying weak magma is calculated for a long mountainous load. The deformations, produce vertical superposed stresses in the lithosphere that contribute to the support of the mountain and distribute its weight over a large area.Employing the principle of isobaric equilibrium, the distribution of the vertical supporting stress and the associated gravity anomalies may be determined by analysis.The results of the analysis are applied to the Hawaiian chain and it is shown that the calculated physical properties and gravity anomalies are remarkably like those observed. It is inferred from the study that: (a) a strong lithosphere underlies the Hawaiians and this section is practically identical with those underlying other regions; (b) the lithosphere will support one-sided stresses approximating 10⁹ dynes/cm.² for long periods of time; (c) the distribution of gravity anomaly may be described quantitatively in terms of the calculated deformations; (d) the principle of isobaric equilibrium is obeyed throughout the region whereas the isostatic principle is generally violated; and (e) the distribution of compensating masses is not at all like that demanded by the principle of isostasy.It is concluded that isostasy leads to results that are clearly wrong when applied to mountains or other deformed regions. The principle of isobaric equilibrium appears, however, to be well established by the investigation.     

Genetic Association of rs2237572 Cyclin-Dependent Kinase 6 Gene with Breast Cancer in Iraq

This case–control study is aimed to evaluate serum concentration of Cyclin-Dependent Kinase 6 (CDK6) and the genetic association between rs2237572 CDK6 gene and breast cancer (BC) in Iraq. To attain this goal, 80 patients with BC as cases and 80 healthy individuals as controls were included. Further, BC patients were sorted according to the molecular classification into four subtypes of Luminal A, Luminal B, Her2/neu enriched and TPN. Serum concentration of CDK6 enzyme, allelic and genotypic frequencies of rs2237572 CDK6, and the occurrence of BC phenotype and its subtypes in the studied population were investigated. ELISA technique was used to perform the biochemical testing, while the molecular analysis was achieved by real-time PCR, high resolution melting analysis, conventional PCR, as well as sequencing analysis. The results revealed no significant difference in serum concentration of CDK6 enzyme between patients and healthy controls (p > 0.05). Also, no significant differences were shown between BC patients subtypes (p > 0.05). The rs2237572 CDK6 genotypes were associated with the BC and affirmed that allele C was inherited as a recessive risk factor. Moreover, a highly significant difference between patients’ subtypes in the genotypic frequency of rs2237572 (p < 0.01) was noted. Furthermore, the association of rs2237572 genotypes and CDK6 serum concentration in BC patients showed a considered significant difference between C/C and T/T, C/C and T/C and the CDK6 level (p < 0.05). Nevertheless, T/T and T/C did not show any significant difference with the CDK6 level. Hence, it was concluded that the rs2237572 of CDK6 gene is significantly correlated with BC.     

Representation matters: An exploration of the socio-economic impacts of ICT-enabled public value in the context of sub-Saharan economies

In this investigation we use a modified Networked Readiness Index (NRI) framework to investigate whether (1) ICT capabilities impact public value creation, and (2) if the public value is associated with the socio-economic impact of ICT capabilities. In the case of this study the construct Public Value is represented via two different proxies. In the first case we use a perception-based measure of public value (as represented by the World Government Indicators) and in the second case we use a surrogate objective measure (as represented by the Cost of Business Startup Procedures (CBSP)). We use a six-step multi-method methodology that involves Cluster Analysis, Correlation Analysis, Decision Trees Induction, Data Envelopment Analysis, Association Rules Mining, and Ordinary Least Squares regression to conduct the inquiry in the context of 26 Sub-Saharan (SSA) economies. Results of our data analysis include: 1) the set of economies with better developed ICT Capabilities are relatively more efficient in converting ICT Capabilities into Public Value than the relatively poorer economies with less developed ICT Capabilities; 2) High levels of ICT capabilities in the areas of Affordability Readiness, Skills Readiness, the Political & Regulatory Environment, and Business Usage allow for relatively more efficient generation of Public Value.     

A systematic analysis of performance measures for classification tasks

This paper presents a systematic analysis of twenty four performance measures used in the complete spectrum of Machine Learning classification tasks, i.e., binary, multi-class, multi-labelled, and hierarchical. For each classification task, the study relates a set of changes in a confusion matrix to specific characteristics of data. Then the analysis concentrates on the type of changes to a confusion matrix that do not change a measure, therefore, preserve a classifier’s evaluation (measure invariance). The result is the measure invariance taxonomy with respect to all relevant label distribution changes in a classification problem. This formal analysis is supported by examples of applications where invariance properties of measures lead to a more reliable evaluation of classifiers. Text classification supplements the discussion with several case studies.     

澜沧江流域潜在蒸散发敏感性分析

蒸散发对气候变量的敏感性研究是近年来水文学的热点之一,对探讨水循环对气候变化的响应具有重要意义。本文利用1960年-2005年澜沧江流域及其周边35个气象站的逐日常规气象观测数据,基于Penman-Monteith公式,计算了1月、7月及年3个不同时间尺度下潜在蒸散发对平均气温、相对湿度、风速及日照时数的敏感系数,分析了澜沧江流域潜在蒸散发对各气候变量的敏感性及其时空变化规律。结果表明各站潜在蒸散发对各变量的敏感系数空间分异明显,流域整体上对日照时数最为敏感。几十年来对日照时数的敏感性在1月主要为增加趋势,7月则为减小趋势。