662 research outputs found

    When Micro Prudence Increases Macro Risk: The Destabilizing Effects of Financial Innovation, Leverage, and Diversification

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    By exploiting basic common practice accounting and risk-management rules, we propose a simple analytical dynamical model to investigate the effects of microprudential changes on macroprudential outcomes. Specifically, we study the consequence of the introduction of a financial innovation that allows reducing the cost of portfolio diversification in a financial system populated by financial institutions having capital requirements in the form of Value at Risk (VaR) constraint and following standard mark-to-market and risk-management rules. We provide a full analytical quantification of the multivariate feedback effects between investment prices and bank behavior induced by portfolio rebalancing in presence of asset illiquidity and show how changes in the constraints of the bank portfolio optimization endogenously drive the dynamics of the balance sheet aggregate of financial institutions and, thereby, the availability of bank liquidity to the economic system and systemic risk. The model shows that when financial innovation reduces the cost of diversification below a given threshold, the strength (because of higher leverage) and coordination (because of similarity of bank portfolios) of feedback effects increase, triggering a transition from a stationary dynamics of price returns to a nonstationary one characterized by steep growths (bubbles) and plunges (bursts) of market prices

    Treatment Needs for Dental Caries, Restorative Care Index, and Index of Extractions in Adolescents 12 and 15 Years Old

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    Objective: To determine the Treatment Needs Index (TNI) for dental caries, the restorative Care Index (CI), and to introduce a Tooth Extractions Index (TEI) to estimate past and current treatment needs among Mexican adolescents. Subjects and methods: A descriptive cross-sectional study was carried out on 1538 adolescents aged 12 and 15 years in the state of Hidalgo, Mexico, to collect decayed, missing, filled teeth (DMFT) data to describe TNI, CI and TEI indices. Results: Higher TNI was identified in younger male teenagers who had always lived in the same community, without dental visits in the last year, and who had poorer socio-economic markers. Higher CI was found in older, female subjects who had moved in their lifetimes to a new community in the area, with dental visits in the last year and who had better socio-economic markers. Higher TEI was found in older, female teenagers who had moved in their lifetimes to a new community in the area, without dental visits in the last year, and who had worse socio-economic markers. Conclusions: We observed high rates of treatment needs for dental caries and little experience of restorative treatment. While dental extractions due to advanced caries should ideally be zero, relatively few adolescents had this treatment experience. Despite the fact that the overall background of these adolescents is rather homogeneous, it was still possible to find that treatment needs' indices (past and present needs) appeared to be modified by sociodemographic and socio-economic variables

    Mind the gap: connexins and cell–cell communication in the diabetic kidney

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    Connexins, assembled as a hexameric connexon, form a transmembrane hemichannel that provides a conduit for paracrine signalling of small molecules and ions to regulate the activity and function of adjacent cells. When hemichannels align and associate with similar channels on opposing cells, they form a continuous aqueous pore or gap junction, allowing the direct transmission of metabolic and electrical signals between coupled cells. Regulation of gap junction synthesis and channel activity is critical for cell function, and a number of diseases can be attributed to changes in the expression/function of these important proteins. Diabetic nephropathy is associated with several complex metabolic and inflammatory responses characterised by defects at the molecular, cellular and tissue level. In both type 1 and type 2 diabetes, glycaemic injury of the kidney is the leading cause of end-stage renal failure, a consequence of multiple aetiologies, including increased deposition of extracellular matrix, glomerular hyperfiltration, albuminuria and tubulointerstitial fibrosis. In diabetic nephropathy, loss of connexin mediated cell–cell communication within the nephron may represent an early sign of disease; however, our current knowledge of the role of connexins in the diabetic kidney is sparse. This review highlights recent evidence demonstrating that maintenance of connexin-mediated cell–cell communication could benefit region-specific renal function in diabetic nephropathy and suggests that these proteins should be viewed as a tantalising novel target for therapeutic intervention

    Computational molecular characterization of the flavonoid rutin

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    In this work, we make use of a model chemistry within Density Functional Theory (DFT) recently presented, which is called M05-2X, to calculate the molecular structure of the flavonoid Rutin, as well as to predict the infrared (IR) and ultraviolet (UV-Vis) spectra, the dipole moment and polarizability, the free energy of solvation in different solvents as an indication of solubility, the HOMO and LUMO orbitals, and the chemical reactivity parameters that arise from Conceptual DFT. The calculated values are compared with the available experimental data for this molecule as a means of validation of the used model chemistry

    Validity of instruments to assess students' travel and pedestrian safety

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    <p>Abstract</p> <p>Background</p> <p>Safe Routes to School (SRTS) programs are designed to make walking and bicycling to school safe and accessible for children. Despite their growing popularity, few validated measures exist for assessing important outcomes such as type of student transport or pedestrian safety behaviors. This research validated the SRTS school travel survey and a pedestrian safety behavior checklist.</p> <p>Methods</p> <p>Fourth grade students completed a brief written survey on how they got to school that day with set responses. Test-retest reliability was obtained 3-4 hours apart. Convergent validity of the SRTS travel survey was assessed by comparison to parents' report. For the measure of pedestrian safety behavior, 10 research assistants observed 29 students at a school intersection for completion of 8 selected pedestrian safety behaviors. Reliability was determined in two ways: correlations between the research assistants' ratings to that of the Principal Investigator (PI) and intraclass correlations (ICC) across research assistant ratings.</p> <p>Results</p> <p>The SRTS travel survey had high test-retest reliability (κ = 0.97, n = 96, p < 0.001) and convergent validity (κ = 0.87, n = 81, p < 0.001). The pedestrian safety behavior checklist had moderate reliability across research assistants' ratings (ICC = 0.48) and moderate correlation with the PI (r = 0.55, p =< 0.01). When two raters simultaneously used the instrument, the ICC increased to 0.65. Overall percent agreement (91%), sensitivity (85%) and specificity (83%) were acceptable.</p> <p>Conclusions</p> <p>These validated instruments can be used to assess SRTS programs. The pedestrian safety behavior checklist may benefit from further formative work.</p

    Reasons Why Erupted Third Molars Are Extracted in a Public University in Mexico

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    Purpose: The aim of this study was to determine the reasons for which erupted third molars (3M) are extracted in a sample of Mexican patients. Subjects and methods: A retrospective cross-sectional study was performed on a sample of 83 patients attending exodontia (minor oral surgery) clinics of a public university in Mexico (Autonomous University of Hidalgo State). The outcome variable was the reason for extractions using Kay and Blinkhorn's classification. The independent variables were age, gender, arch and tooth number according to the World Health Organization (WHO). For statistical analysis, we used the Chi-squared test in Stata 9.0. Results: Eighty-three patients underwent 150 3M extractions. Mean age was 38.67 ± 13.96 years, and 71.1% were female. The four reasons for 3M extraction were prosthetic (44.0%), followed by orthodontic (24.7%), dental caries (20.0%) and periodontal disease (11.3%). Differences were observed in the reasons for 3M extractions across age groups (p 0.05), or the WHO tooth number (p > 0.05). Conclusion: Women and patients 18 to 34 years of age had erupted 3M extracted more frequently, primarily for prosthetic reasons. The age profile indicated a trend in demand for services that differ from those of overall tooth extractions, but not for the trend across gender

    Statewide Systematic Evaluation of Sudden, Unexpected Infant Death Classification: Results from a National Pilot Project

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    The Centers for Disease Control and Prevention funded seven states, including Kentucky, to clarify statewide death certification practices in sudden, unexpected infant death and compare state performances with national expectations. Accurate assignment of the cause and manner of death in cases of sudden, unexpected infant death is critical for accurate vital statistics data to direct limited resources to appropriate targets, and to implement optimal and safe risk reduction strategies. The primary objectives are to (1) Compare SUID death certifications recommended by the KY medical examiners with the stated cause of death text field on the hard copy death electronic death certificates and (2) Compare KY and national SUID rates. Causes of death for SUID cases recommended by the medical examiners and those appearing on the hard copy and electronic death certificates in KY were collected retrospectively for 2004 and 2005. Medical examiner recommendations were based upon a classification scheme devised by them in 2003. Coroners hard copy death certificates and the cause of death rates in KY were compared to those occurring nationally. Eleven percent of infants dying suddenly and unexpectedly did not undergo autopsy during the study interval. The KY 2003 classification scheme for SIDS is at variance with the NICHD and San Diego SIDS definitions. Significant differences in causes of death recommended by medical examiners and those appearing on the hard copy and electronic death certificates were identified. SIDS rates increased in KY in contrast to decreasing rates nationally. Nationwide adoption of a widely used SIDS definition, such as that proposed in San Diego in 2004 as well as legislation by states to ensure autopsy in all cases of sudden unexpected infant death are recommended. Medical examiners’ recommendations for cause of death should appear on death certificates. Multidisciplinary pediatric death review teams prospectively evaluating cases before death certification is recommended. Research into other jurisdictions death certification process is encouraged

    Pilot evaluation of a walking school bus program in a low-income, urban community

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    <p>Abstract</p> <p>Background</p> <p>To evaluate the impact of a walking school bus (WSB) program on student transport in a low-income, urban neighborhood.</p> <p>Methods</p> <p>The design was a controlled, quasi-experimental trial with consecutive cross-sectional assessments. The setting was three urban, socioeconomically disadvantaged, public elementary schools (1 intervention vs. 2 controls) in Seattle, Washington, USA. Participants were ethnically diverse students in kindergarten-5<sup>th </sup>grade (aged 5–11 years). The intervention was a WSB program consisting of a part-time WSB coordinator and parent volunteers. Students' method of transportation to school was assessed by a classroom survey at baseline and one-year follow-up. The Pearson Chi-squared test compared students transported to school at the intervention versus control schools at each time point. Due to multiple testing, we calculated adjusted p-values using the Ryan-Holm stepdown Bonferroni procedure. McNemar's test was used to examine the change from baseline to 12-month follow-up for walking versus all other forms of school transport at the intervention or control schools.</p> <p>Results</p> <p>At baseline, the proportions of students (n = 653) walking to the intervention (20% +/- 2%) or control schools (15% +/- 2%) did not differ (<it>p </it>= 0.39). At 12-month follow up, higher proportions of students (n = 643, <it>p </it>= 0.001)) walked to the intervention (25% +/- 2%) versus the control schools (7% +/- 1%). No significant changes were noted in the proportion of students riding in a car or taking the school bus at baseline or 12-month follow up (all <it>p </it>> 0.05). Comparing baseline to 12-month follow up, the numbers of students who walked to the intervention school increased while the numbers of students who used the other forms of transport did not change (<it>p </it>< 0.0001). In contrast, the numbers of students who walked to the control schools decreased while the numbers of students who used the other forms of transport did not change (<it>p </it>< 0.0001).</p> <p>Conclusion</p> <p>A WSB program is a promising intervention among urban, low-income elementary school students that may promote favorable changes toward active transport to school.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00402701</p

    Search For Heavy Pointlike Dirac Monopoles

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    We have searched for central production of a pair of photons with high transverse energies in ppˉp\bar p collisions at s=1.8\sqrt{s} = 1.8 TeV using 70pb−170 pb^{-1} of data collected with the D\O detector at the Fermilab Tevatron in 1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of 610,870,or1580GeV/c2610, 870, or 1580 GeV/c^2 on the mass of a spin 0, 1/2, or 1 Dirac monopole.Comment: 12 pages, 4 figure
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