Effect of changing data size on eigenvalues in the Korean and Japanese stock markets

In this study, we attempted to determine how eigenvalues change, according to random matrix theory (RMT), in stock market data as the number of stocks comprising the correlation matrix changes. Specifically, we tested for changes in the eigenvalue properties as a function of the number and type of stocks in the correlation matrix. We determined that the value of the eigenvalue increases in proportion with the number of stocks. Furthermore, we noted that the largest eigenvalue maintains its identical properties, regardless of the number and type, whereas other eigenvalues evidence different features

Replication of Known Dental Characteristics in Porcine Skin: Emerging Technologies for the Imaging Specialist

This study demonstrates that it is sometimes possible to replicate patterns of human teeth in pig skin and determine scientifically that a given injury pattern (bite mark) correlates with the dentitions of a very small proportion of a population dataset, e.g., 5 percent or even 1 percent. The authors recommend building on the template of this research with a sufficiently large database of samples that reflects the diverse world population. They also envision the development of a sophisticated imaging software application that enables forensic examiners to insert parameters for measurement, as well as additional methods of applying force to produce bite marks for research. The authors further advise that this project is applied science for injury pattern analysis and is only foundational research that should not be cited in testimony and judicial procedures. It supplements but does not contradict current guidelines of the American Board of Forensic Odontology regarding bite mark analysis and comparisons. A much larger population database must be developed. The project’s methodology is described in detail, accompanied by 11 tables and 41 figures

Monitoring socioeconomic inequalities in health in Hong Kong: insights and lessons from the UK and Australia

In many developed countries such as the UK and Australia, addressing socioeconomic inequalities in health is a priority in their policy agenda, with well-established practices and authorities to collect and link selected health and social indicators for long-term monitoring. Nonetheless, the monitoring of socioeconomic inequalities in health in Hong Kong remains in a piecemeal manner. Also, the common international practice to monitor inequalities at area level appears to be unsuitable in Hong Kong due to its small, compact, and highly interconnected built environment that limits the variation of neighbourhood deprivation level. To enhance inequality monitoring in Hong Kong, we aim to draw reference and lesson from the UK and Australia to explore the feasible steps forward regarding collection of health indicators and contextually appropriate equity stratifiers with strong implication on policy actions, and discuss potential strategies to promote the public awareness and motivations for a more comprehensive inequality monitoring system

A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind

This paper studies the turbulent cascade of magnetic energy in weakly collisional magnetized plasmas. A cascade model is presented, based on the assumptions of local nonlinear energy transfer in wavenumber space, critical balance between linear propagation and nonlinear interaction times, and the applicability of linear dissipation rates for the nonlinearly turbulent plasma. The model follows the nonlinear cascade of energy from the driving scale in the MHD regime, through the transition at the ion Larmor radius into the kinetic Alfven wave regime, in which the turbulence is dissipated by kinetic processes. The turbulent fluctuations remain at frequencies below the ion cyclotron frequency due to the strong anisotropy of the turbulent fluctuations, k_parallel << k_perp (implied by critical balance). In this limit, the turbulence is optimally described by gyrokinetics; it is shown that the gyrokinetic approximation is well satisfied for typical slow solar wind parameters. Wave phase velocity measurements are consistent with a kinetic Alfven wave cascade and not the onset of ion cyclotron damping. The conditions under which the gyrokinetic cascade reaches the ion cyclotron frequency are established. Cascade model solutions imply that collisionless damping provides a natural explanation for the observed range of spectral indices in the dissipation range of the solar wind. The dissipation range spectrum is predicted to be an exponential fall off; the power-law behavior apparent in observations may be an artifact of limited instrumental sensitivity. The cascade model is motivated by a programme of gyrokinetic simulations of turbulence and particle heating in the solar wind.Comment: 29 pages, 14 figure

The affects of genistein on the Bradyrhizobium japonicum bacterial transcriptome [abstract]

Abstract only availableFaculty Mentor: Gary Stacey, Plant Microbiology and PathologyBradyrhizobium japonicum forms a symbiotic relationship with the roots of the soybean plant (Glycine max). This bacterium is of great importance because of its ability to provide the soybean with a source of nitrogen by the conversion of atmospheric dinitrogen to ammonia. In order to establish this symbiosis, the bacteria must attach to the root hair surface and initiate development of a root nodule. The bacterium responds to plant flavonoids through production of nod factor, a product of the nod genes, which facilitates bacterial root entry and initiates nodule organogenesis. Therefore, we have investigated the expression of nod genes after treatment with a plant derived flavonoid inducer, genistein. Free-living cultures of Bradyrhizobium japonicum were treated and cells were harvested six hours after treatment and total RNA was extracted. Semi-quantitative and quantitative RT-PCR was performed to confirm induction of the nodY and nodC genes. The RT-PCR results confirmed that nodY and nodC are upregulated in the presence of genistein compared to an ethanol-treated control. To further define genistein regulation on the nod genes, a DNA microarray experiment was performed on the above extracted RNA to define the bacterial transcriptional response to genistein, the results of which will be presented.Bradyrhizobium japonicum forms a symbiotic relationship with the roots of the soybean plant (Glycine max).  This bacterium is of great importance because of its ability to provide the soybean with a source of nitrogen by the conversion of atmospheric dinitrogen to ammonia.   In order to establish this symbiosis, the bacteria must attach to the root hair surface and initiate development of a root nodule.  The bacterium responds to plant flavonoids through production of nod factor, a product of the nod genes, which facilitates bacterial root entry and initiates nodule organogenesis. Therefore, we have investigated the expression of nod genes after treatment with a plant derived flavonoid inducer, genistein. Free-living cultures of Bradyrhizobium japonicum were treated and cells were harvested six hours after treatment and total RNA was extracted.  Semi-quantitative and quantitative RT-PCR was performed to confirm induction of the nodY and nodC genes. The RT-PCR results confirmed that nodY and nodC are upregulated in the presence of genistein compared to an ethanol-treated control.  To further define genistein regulation on the nod genes, a DNA microarray experiment was performed on the above extracted RNA to define the bacterial transcriptional response to genistein, the results of which will be presented

Finding effective support-tree preconditioners

In 1995, Gremban, Miller, and Zagha introduced support-tree preconditioners and a parallel algorithm called support-tree conjugate gradient (STCG) for solving linear systems of the form Ax = b, where A is an n × n Laplacian matrix. A Laplacian is a symmetric matrix in which the off-diagonal entries are non-positive, and the row and column sums are zero. A Laplacian A with 2m non-zeros can be interpreted as an undirected positively-weighted graph G with n vertices and m edges, where there is an edge between two nodes i and j with weight c((i, j)) = −Ai,j = −Aj,i if Ai,j = Aj,i &lt; 0. Gremban et al. showed experimentally that STCG performs well on several classes of graphs commonly used in scientific computations. In his thesis, Gremban also proved upper bounds on the number of iterations required for STCG to converge for certain classes of graphs. In this paper, we present an algorithm for finding a preconditioner for an arbitrary graph G = (V, E) with n nodes, m edges, and a weight function c&gt; 0 on the edges, where w.l.o.g., mine∈E c(e) = 1. Equipped with this preconditioner, STCG requires O(log 4 n · � ∆/α) iterations, where α = min U⊂V,|U|≤|V |/2 c(U, V \U)/|U | is the minimum edge expansion of the graph, and ∆ = maxv∈V c(v) is the maximum incident weight on any vertex. Each iteration requires O(m) work and can be implemented in O(log n) steps in parallel, using only O(m) space. Our results generalize to matrices that are symmetric and diagonally-dominant (SDD).

Type 2 innate immunity drives distinct neonatal immune profile conducive for heart regeneration.

Neonatal immunity is functionally immature and skewed towards a T 2-driven, anti-inflammatory profile. This neonatal immunotolerance is partly driven by the type 2 cytokines: interleukin-4 (IL-4) and interleukin-13 (IL-13). Studies on neonatal cardiac regeneration reveal the beneficial role of an anti-inflammatory response in restoring cardiac function after injury. However, the role of an imbalanced immune repertoire observed in neonates on tissue regeneration is poorly understood; specifically, whether IL-4 and IL-13 actively modulate neonatal immunity during cardiac injury. Neonatal mice lacking IL-4 and IL-13 (DKOs) examined at 2 days after birth exhibited reduced anti-inflammatory immune populations with basal cardiac immune populations like adult mice. Examination of neonates lacking IL-4 and IL-13 at 2 days post cardiac ischemic injury, induced on the second day after birth, showed impaired cardiac function compared to their control counterparts. Treatment with either IL-4 or IL-13 cytokine during injury restored both cardiac function and immune population profiles in knockout mice. Examination of IL-4/IL-13 downstream pathways revealed the role of STAT6 in mediating the regenerative response in neonatal hearts. As IL-4/IL-13 drives polarization of alternatively activated macrophages, we also examined the role of IL-4/IL-13 signaling within the myeloid compartment during neonatal cardiac regeneration. Injury of IL-4Rα myeloid specific knockout neonates 2 days after birth revealed that loss of IL-4/IL-13 signaling in macrophages alone was sufficient to impair cardiac regeneration. Our results confirm that the T 2 cytokines: IL-4 and IL-13, which skews neonatal immunity to a T 2 profile, are necessary for maintaining and mediating an anti-inflammatory response in the neonatal heart, in part through the activation of alternatively activated macrophages, thereby permitting a niche conducive for regeneration. [Abstract copyright: © The author(s).

Inhibition of Soluble Epoxide Hydrolase Limits Mitochondrial Damage and Preserves Function Following Ischemic Injury

Aims: Myocardial ischemia can result in marked mitochondrial damage leading to cardiac dysfunction, as such identifying novel mechanisms to limit mitochondrial injury is important. This study investigated the hypothesis that inhibiting soluble epoxide hydrolase (sEH), responsible for converting epoxyeicosatrienoic acids to dihydroxyeicosatrienoic acids protects mitochondrial from injury caused by myocardial infarction. Methods: sEH null and WT littermate mice were subjected to surgical occlusion of the left anterior descending (LAD) artery or sham operation. A parallel group of WT mice received an sEH inhibitor, trans-4-[4-(3-adamantan-1-y1-ureido)-cyclohexyloxy]-benzoic acid (tAUCB; 10 mg/L) or vehicle in the drinking water 4 days prior and 7 days post-MI. Cardiac function was assessed by echocardiography prior- and 7-days post-surgery. Heart tissues were dissected into infarct, peri-, and non-infarct regions to assess ultrastructure by electron microscopy. Complexes I, II, IV, citrate synthase, PI3K activities, and mitochondrial respiration were assessed in non-infarct regions. Isolated working hearts were used to measure the rates of glucose and palmitate oxidation. Results: Echocardiography revealed that tAUCB treatment or sEH deficiency significantly improved systolic and diastolic function post-MI compared to controls. Reduced infarct expansion and less adverse cardiac remodeling were observed in tAUCB-treated and sEH null groups. EM data demonstrated mitochondrial ultrastructure damage occurred in infarct and peri-infarct regions but not in non-infarct regions. Inhibition of sEH resulted in significant improvements in mitochondrial respiration, ATP content, mitochondrial enzymatic activities and restored insulin sensitivity and PI3K activity. Conclusion: Inhibition or genetic deletion of sEH protects against long-term ischemia by preserving cardiac function and maintaining mitochondrial efficiency

Importance of randomization in microarray experimental designs with Illumina platforms

Measurements of gene expression from microarray experiments are highly dependent on experimental design. Systematic noise can be introduced into the data at numerous steps. On Illumina BeadChips, multiple samples are assayed in an ordered series of arrays. Two experiments were performed using the same samples but different hybridization designs. An experiment confounding genotype with BeadChip and treatment with array position was compared to another experiment in which these factors were randomized to BeadChip and array position. An ordinal effect of array position on intensity values was observed in both experiments. We demonstrate that there is increased rate of false-positive results in the confounded design and that attempts to correct for confounded effects by statistical modeling reduce power of detection for true differential expression. Simple analysis models without post hoc corrections provide the best results possible for a given experimental design. Normalization improved differential expression testing in both experiments but randomization was the most important factor for establishing accurate results. We conclude that lack of randomization cannot be corrected by normalization or by analytical methods. Proper randomization is essential for successful microarray experiments