关于中心厄米特矩阵的广义反特征值问题

1　Introduction　AmatrixA∈Cn×missaidtobecentrohermitianifA =Jn AJm,andskewcentrohermitianifA =-Jn AJm,where Adenotetheconjugateofthema trixAandJlisthepermutationmatrixoforderlwithonesonthecrossdiagonal(bottomlefttotopright)andzeroselsewhere .ThehermitianToeplitzmatricesformanimportantsubclassofcentrohermi tianmatriceswhichoccurnaturallyindigitalsignalprocessingandotherareas ,seeforinstance[1] andreferencetherein .Thecentrohermitianandrelatedmatricesrecentlyplayanimportantroleinthesolu…     

Points at Which Continuous Functions Have the Same Height

As an easy application of the intermediate value theorem, one can show that for any continuous function f: [0, 1] → ? with f (0) = f (1), there are points a, a + 1/2 both in [0, 1] such that f (a) = f (a + 1/2). In this note, we show that this property holds with 1/2 replaced by any number of the form 1/n for a positive integer n. More interestingly, we show that this is false for every number not of the form 1/n.     

Introduction to the LASSO

The term ‘high-dimensional’ refers to the case where the number of unknown parameters to be estimated, p, is of much larger order than the number of observations, n, that is p ? n. Since traditional statistical methods assume many observations and a few unknown variables, they can not cope up with the situations when p ? n. In this article, we study a statistical method, called the ‘Least Absolute Shrinkage and Selection Operator’ (LASSO), that has got much attention in solving high-dimensional problems. In particular, we consider the LASSO for high-dimensional linear regression models. We aim to provide an introduction of the LASSO method as a constrained quadratic programming problem, and we discuss the convex optimization based approach to solve the LASSO problem. We also illustrate applications of LASSO method using a simulated and a real data examples.     

Control mesh representation of a class of minimal surfaces

INTRODUCTION The problem of minimal surface is an old and active problem in the field of differential geometry. The minimal surface has been employed in many areas such as architecture, material science, aviation, ship manufacture, biology, crystallogeny, and so on. The history of minimal surface began with La- grange in 1762 (Nitsche, 1989). Many literature on the minimal surface exist in the last two hundred years (Nitsche, 1989; Osserman, 1986), but few on the minimal surface from the…     

Fecal Microbiota Succession of Piglets from Birth to Post-weaning by 454 Pyrosequencing Analysis

The objective of this study was to describe the fecal microbiota succession of piglets from birth to post-weaning by pyrosequencing. The dominant bacterial phyla were Bacteroidetes, Firmicutes, Proteobacteria, and Fusobacteria, although the composition of the fecal microbiota changed as the piglets grew. Bacteroides, Parabacteroides, Prevotella, Lactobacillus, unclassified Lachnospiraceae, Ruminococcus, Oscillospira, Phascolarctobacterium, and Desulfovibrio were the core genera in the feces of piglets and existed from birth to post-weaning. Bacteroides was the most abundant at birth; however, the proportion of Bacteroides decreased as the piglets aged, while the proportion of Prevotella increased until it became the most abundant genus at the post-weaning stage. Principal coordinate analysis indicated that the microbial communities of piglet fecal samples from birth to post-weaning could be separated into four groups according to the similarity of community composition. These corresponded to time points on day 0 (birth); day 7; days 14, 21, and 28 (pre-weaning); and day 35 (post-weaning). This study suggests that the development of the intestinal microbiota in the piglet is a gradual and sequential process. This methodology establishes a basis for broader studies to investigate the microbiota of the piglet intestinal tract.     

Optimal multi-degree reduction of Bézier curves with <Emphasis Type="Italic">G</Emphasis><Superscript>1</Superscript>-continuity

This paper presents a novel approach to consider optimal multi-degree reduction of Bézier curve with G¹-continuity. By minimizing the distances between corresponding control points of the two curves through degree raising, optimal approximation is achieved. In contrast to traditional methods, which typically consider the components of the curve separately, we use geometric information on the curve to generate the degree reduction. So positions and tangents are preserved at the two endpoints. For satisfying the solvability condition, we propose another improved algorithm based on regularization terms. Finally, numerical examples demonstrate the effectiveness of our algorithms.     

Making Space for Consuming Practices

This empirically driven paper is about workplace learning with specific focus on the ‘work’ of consuming practices. By consuming we refer to the eating, and the drinking, and (at times) to the smoking that workers, in most organisations, do on a daily basis. Indeed, it is the quotidian nature of consuming, coupled with its absence from workplace learning research that make them noteworthy practices to explore. In using the term practice we draw on the recent tranche of practice based theorisations: notably Schatzki (1996, Organization Studies, 26(3), 465-484, 2005, Organization Studies, 27(12), 1863-1873, 2006) and Gherardi (Human Relations, 54(1), 131-139, 2001, 2006, Learning Organization, 16(5), 352-359, 2009). The paper frames consuming practices as ‘dispersed’ (general) practices and, illustrated through empirical data from multiple projects, we progressively outline how these contribute to the learning of ‘integrative’ (specialized work) practices. Our overall aim is to (re)position consuming practices from prosaic, to having much relevance for research on workplace learning.     

The Comtesse de Genlis’ <Emphasis Type="Italic">Théâtre à l’usage des jeunes personnes</Emphasis> (1779–1780): Educating for Order and Prejudice in Pre-revolutionary France

This essay explores the educational contribution of the Comtesse de Genlis’ Théâtre à l'usage des jeunes personnes [Theatre of Education] (1792/1779–1780), a four-volume collection of closet drama, in light of the social, political and cultural shifts occurring in France in the period prior to the French Revolution. In particular, in two plays from Theatre of Education, La Marchande de Modes [The Milliner] and Le Libraire [The Bookseller], Genlis depicts the bourgeoisie’s proper behaviour toward the aristocracy and its natural place in the world. Thus both plays exemplify the educational and the political role of Genlis, who attempts to tame the bourgeoisie through the twofold argument of proper education and effective parenthood, so as to keep alive the social order of the ancien régime.     

Prevalence and genotype of <Emphasis Type="Italic">Chlamydia psittaci</Emphasis> in faecal samples of birds from zoos and pet markets in Kunming,Yunnan, China

Chlamydia psittaci is an important zoonotic pathogen in birds and may be transmitted to humans and result in severe respiratory disease. To assess the prevalence and genotype of C. psittaci in birds in Kunming, Yunnan, China, a total of 136 specimens of psittacine birds involving 8 species were collected from the city’s zoos (n=60) and pet markets (n=76). The frequency of C. psittaci infection was 19.9% (27/136) in the psittacine birds. The prevalence of C. psittaci was higher in pet birds (26.3%; 20/76) than in zoo birds (11.7%; 7/60) (P=0.034). In particular, among Agapornis fischeri, the C. psittaci infection (50%; 10/20) was significantly more frequent in the pet markets than in the zoos (P=0.006). In addition, the highest prevalence of 41.2% (7/17) was found in Ara ararauna. To determine the genotype of C. psittaci, 23 OmpA gene fragments (about 1.4 kb) in 27 positive samples were successfully amplified and sequenced. Phylogenetic analysis showed that all the 23 strains belonged to genotype A. Our results demonstrate the high prevalence of C. psittaci genotype A infection in psittacine birds in Yunnan Province, suggesting a potential threat to human health in this area. Therefore, it is necessary to take effective measures to prevent the spread of C. psittaci among psittacine birds, as well as among employees and customers.     

On a Problem of Alaoglu and Erdős

Starting with an elementary problem that appeared in the Putnam mathematics competition, we proceed to discuss some techniques of transcendental number theory and prove the following result. If p, q, r are distinct primes and if c is a real number with the property that p^c, q^c, r^c are integers, then c must be a non-negative integer. The tools used are some linear algebra and complex analysis. The zero-density estimate method discussed here was used by Alan Baker to prove his celebrated theorem on linear forms in logarithms. The question as to whether we can replace three primes by two primes is an open question.     

Not playing the game: student assessment resistance as a form of agency

Within self-regulated learning, learners exercise agency by setting targets, formatively monitoring progress, and evaluating results in ways which inform their own goal attainment. However, in real-world classroom situations, assessment processes can elicit behaviours that are more ego-protective than growth-oriented. Resistance to teacher expectations in assessment can arise from the individual’s need to protect his or her own identity or ego within the psychosocial context of the classroom. In addition, resistance can arise from strategic choices learners make to cope with competing demands on their time and resources. Thus, students may exercise their agency by not following assessment expectations or protocols (e.g. lying, cheating, or failing to give their best effort). These choices seem to undermine assessment validity. This paper shares student voice data from the Measuring Teachers’ Assessment Practices (MTAP) project (n = 46 students in seven focus groups) in New Zealand and the Supporting Student-assessment Success (SSAS) Project (n = 108 first-year university students) in Australia. Both highlight the different ways students resist, subvert, or act in contention with assessment. These data show that students in both sectors do not always act in the growth-oriented ways that educators envision. Students reported exercising potentially maladaptive assessment agency via Assessment dishonesty, Purposeful underperformance, and Doing it alone. These categories were underpinned by three differing rationales: Protection, Strategic prioritisation, and Mini-max. Educators must be mindful of these potential student actions and motives, working to establish psychological safety within the learning environment, and making sure links between learning and assessment are clear.     

An oriental melon 9-lipoxygenase gene <Emphasis Type="Italic">CmLOX09</Emphasis> response to stresses,hormones, and signal substances

In plants, lipoxygenases (LOXs) play a crucial role in biotic and abiotic stresses. In our previous study, five 13-LOX genes of oriental melon were regulated by abiotic stress but it is unclear whether the 9-LOX is involved in biotic and abiotic stresses. The promoter analysis revealed that CmLOX09 (type of 9-LOX) has hormone elements, signal substances, and stress elements. We analyzed the expression of CmLOX09 and its downstream genes—CmHPL and CmAOS—in the leaves of four-leaf stage seedlings of the oriental melon cultivar “Yumeiren” under wound, hormone, and signal substances. CmLOX09, CmHPL, and CmAOS were all induced by wounding. CmLOX09 was induced by auxin (indole acetic acid, IAA) and gibberellins (GA₃); however, CmHPL and CmAOS showed differential responses to IAA and GA₃. CmLOX09, CmHPL, and CmAOS were all induced by hydrogen peroxide (H₂O₂) and methyl jasmonate (MeJA), while being inhibited by abscisic acid (ABA) and salicylic acid (SA). CmLOX09, CmHPL, and CmAOS were all induced by the powdery mildew pathogen Podosphaera xanthii. The content of 2-hexynol and 2-hexenal in leaves after MeJA treatment was significantly higher than that in the control. After infection with P. xanthii, the diseased leaves of the oriental melon were divided into four levels—levels 1, 2, 3, and 4. The content of jasmonic acid (JA) in the leaves of levels 1 and 3 was significantly higher than that in the level 0 leaves. In summary, the results suggested that CmLOX09 might play a positive role in the response to MeJA through the hydroperoxide lyase (HPL) pathway to produce C6 alcohols and aldehydes, and in the response to P. xanthii through the allene oxide synthase (AOS) pathway to form JA.     

Individual and Institutional Productivity in Educational Psychology Journals from 2009 to 2014

This article examines the productivity of both individuals and institutions, indexed through an examination of five educational psychology journals (Cognition and Instruction, Contemporary Educational Psychology, Educational Psychologist, Educational Psychology Review, and Journal of Educational Psychology) from 2009 to 2014. These results are discussed relative to four previous studies (Hsieh et al. Contemporary Educational Psychology, 29, 333–343, 2004; Jones et al. Contemporary Educational Psychology, 35, 11–16, 2010; Smith et al. Contemporary Educational Psychology, 23, 173–181, 1998; Contemporary Educational Psychology, 28, 422–430, 2003). Vanderbilt University and Fred Paas replaced the University of Maryland and Richard E. Mayer as the top research institution and author, respectively. Sixteen of the top 19 researchers’ institutions were outside the USA, compared to only 10 of the top 32 during 2003–2008 and three of the top 20 during 1991–1996. Educational psychology research continues the trend of becoming more international.     

Biosynthesis of (<Emphasis Type="Italic">R</Emphasis>)-2-hydroxy-3-phenylpropionic acid using whole recombinant <Emphasis Type="Italic">Escherichia coli</Emphasis> cells in an aqueous/<Emphasis Type="Italic">n</Emphasis>-octane biphasic system

(R)-2-hydroxy-3-phenylpropionic acid (PLA) is an ideal antimicrobial compound with broad-spectrum activity against a wide range of Gram-positive bacteria, some Gram-negative bacteria, and fungi. We studied the bioconversion of phenylpyruvate (PPA) to PLA using whole recombinant Escherichia coli cells in a series of buffer/organic solvent systems. Octane was found to be the best organic solvent. The optimum volume ratio of the water phase to the n-octane phase, conversion temperature, substrate concentration, and cell concentration were 6:4, 40 °C, 12.5 g/L, and 30 g/L wet cells, respectively. Under the optimized conditions, the average PLA productivity in the aqueous/n-octane system was 30.69% higher than that in the aqueous system, and 32.31 g/L PLA was obtained with the use of a stirred reactor (2-L scale). Taken together, our findings indicated that PLA biosynthesis was more efficient in an aqueous/n-octane biphasic system than in a monophasic aqueous system. The proposed biphasic system is an effective strategy for enhancing PLA yield and the biosynthesis of its analogues.     

Follicle-stimulating hormone increases the intramuscular fat content and expression of lipid biosynthesis genes in chicken breast muscle

Intramuscular fat (IMF) is a crucial factor in the quality of chicken meat. The genetic basis underlying it is complex. Follicle-stimulating hormone (FSH), well-known as an effector in reproductive tissues, was recently discovered to stimulate abdominal fat accumulation in chicken. The effect of FSH on IMF accumulation and the underlying molecular regulatory mechanisms controlling both IMF and abdominal fat deposition in vivo are largely unknown. In this study, two groups of chickens were treated with chicken FSH or a placebo. The lipid content of breast muscle, abdominal fat volume, and serum concentrations of FSH were examined. Related genes implicated in breast muscle and abdominal fat accumulation were also investigated. Compared to the control group, the triglyceride (TG) content of breast muscle and the percentage of abdominal fat in FSH-treated chickens were significantly increased by 64.9% and 56.5% (P<0.01), respectively. The FSH content in the serum of FSH-treated chickens was 2.1 times than that of control chickens (P<0.01). Results from quantitative real-time polymerase chain reaction (qRT-PCR) assays showed that relative expression levels of fatty acid synthase (FAS), lipoprotein lipase (LPL), diacylglycerol acyltransferase 2 (DGAT2), adipocyte fatty acid binding protein (A-FABP), and peroxisome proliferator-activated receptor γ (PPARγ) were significantly upregulated in breast muscle following FSH treatment (P<0.01). Treatment with FSH also significantly increased relative expression levels of FAS, LPL, DGAT2, A-FABP, and PPARγ in abdominal fat tissue (P<0.05). The results of principal component analysis (PCA) for gene expression (breast muscle and abdominal fat) showed that the control and FSH treatment groups were well separated, which indicated the reliability of the data. This study demonstrates that FSH plays an important role in IMF accumulation in female chickens, which likely involves the regulation of biosynthesis genes related to lipid metabolism.     

<Emphasis Type="Italic">Pediococcus Acidilactici</Emphasis> Inhibit Biofilm Formation of Food-Borne Pathogens on Abiotic Surfaces

In this study, we aimed to examine the inhibitory effect of PA003, a Pediococcus acidilactici that produces lactic acid and antimicrobial peptides pediocin, on pathogenic biofilm formation on abiotic surfaces. PA003 and pathogens (Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus and Listeria monocytogenes) were used to evaluate auto-aggregation, hydrophobicity, biofilm formation and biofilm formation inhibition on stainless steel, polyvinyl chloride and glass slides in terms of exclusion, displacement and competition. The results showed the highest auto-aggregation abilities were observed for one of the E. coli strains EAggEC (E58595) and the highest hydrophobic strain was observed with EPEC (E2348/69) (51.9%). The numbers of biofilm cells of E. coli, S. Typhimurium, S. aureus and L. monocytogenes on stainless steel, polyvinyl chloride and glass slide coupons were effectively reduced by approximately 4 log CFU/coupon. These results demonstrate that lactic acid bacteria can be used as an alternative to effectively control the formation of biofilms by food-borne pathogens.     

Glycyrrhizic acid activates chicken macrophages and enhances their <Emphasis Type="Italic">Salmonella</Emphasis>-killing capacity in vitro

Objective

Salmonella enterica remains a major cause of food-borne disease in humans, and Salmonella Typhimurium (ST) contamination of poultry products is a worldwide problem. Since macrophages play an essential role in controlling Salmonella infection, the aim of this study was to evaluate the effect of glycyrrhizic acid (GA) on immune function of chicken HD11 macrophages.

Methods

Chicken HD11 macrophages were treated with GA (0, 12.5, 25, 50, 100, 200, 400, or 800 μg/ml) and lipopolysaccharide (LPS, 500 ng/ml) for 3, 6, 12, 24, or 48 h. Evaluated responses included phagocytosis, bacteria-killing, gene expression of cell surface molecules (cluster of differentiation 40 (CD40), CD80, CD83, and CD197) and antimicrobial effectors (inducible nitric oxide synthase (iNOS), NADPH oxidase-1 (NOX-1), interferon-γ (IFN-γ), LPS-induced tumor necrosis factor (TNF)-α factor (LITAF), interleukin-6 (IL-6), and IL-10), and production of nitric oxide (NO) and hydrogen peroxide (H₂O₂).

Results

GA increased the internalization of both fluorescein isothiocyanate (FITC)-dextran and ST by HD11 cells and markedly decreased the intracellular survival of ST. We found that the messenger RNA (mRNA) expression of cell surface molecules (CD40, CD80, CD83, and CD197) and cytokines (IFN-γ, IL-6, and IL-10) of HD11 cells was up-regulated following GA exposure. The expression of iNOS and NOX-1 was induced by GA and thereby the productions of NO and H₂O₂ in HD11 cells were enhanced. Notably, it was verified that nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) pathways were responsible for GA-induced synthesis of NO and IFN-γ gene expression.

Conclusions

Taken together, these results suggested that GA exhibits a potent immune regulatory effect to activate chicken macrophages and enhances Salmonella-killing capacity.

     

Child Readers and the Worlds of the Picture Book

Children as readers of picture books and the ways they respond to, and make meaning from, such texts are the focus of this article, which reports on a small-scale study undertaken in Norway and Wales, UK. The theoretical framing of the research draws on concepts of the multimodal ensemble in picture books and of the reading event as part of a social practice. The research design was developed from the team’s analysis of two texts, Pappa by Svein Nyhus (1998) and What does Daddy Do? by Rachel Bright (2009). Twenty-four children, who were 7 and 8 years old, took part in the study. This was built around two reading events for each book, staged as an immediate response and as a guided response. The data subsequently collected were analysed according to three overarching organisational principles, as book world, real world and play world. For both Daddy and Pappa, the first reading event showed the children’s responses were mainly directed towards exploring the book world. On the second reading event, references to the real world predominated for Daddy, while for Pappa the book world was again dominant. Across both reading events and for both books, the playworld revealed those occasions when the children expanded the meaning of the story, demonstrating an inventive ability to play with the text. Overall, the children’s responses moved fluidly across the three worlds, showing them to be energetically making connections between the reading, their experience of books and their own lives.     

Teachers’ use of Facebook and teacher quality: developing a ‘Facebook Effect Scale on Teacher Quality (FESTQ)’ from the perspective of PCK,TPACK, and lifelong learning frameworks

The main purpose of the study is to develop a Facebook Effect Scale on Teacher Quality (FESTQ) based on the pedagogical content knowledge, technological pedagogical content knowledge and lifelong learning frameworks. Study participants comprised 556 teachers. Explanatory factor analysis and confirmatory factor analysis were conducted in the development and testing of the FESTQ. The results showed that the FESTQ is reliable and valid to measure Facebook effect on teacher quality. The FESTQ consists of 40 positive six-point Likert-type items along with six factors, instructional knowledge for in-class applications, general culture knowledge, individual characteristics, instructional knowledge related to student characteristics, instructional knowledge for preparing an assessment tool and special content area knowledge. The psychometric properties of the FESTQ, the study limitations and suggestions for future studies are discussed.