1,090 research outputs found

    Phasing operator for two oscillators in classical field

    Get PDF
    The origin of Dicke cooperative states was studied by considering two harmonic oscillators driven by a common field of radiation. The origin is assumed for superradiance in a system of molecules where no mutual interactions exist, but all of the molecules encounter the same field of radiation. A phasing operator as Phi(sub Nu) equals D(alpha) + P(sub Nu)D(alpha), where D(alpha) is the displacing operator and P(sub Nu) the projection operator for constant energy Nu for two oscillators, was derived. The eigenstates of the phasing operator Phi are found to show a finite correlation as in the Dicke cooperative states

    Crystallization and preliminary crystallographic studies of an antimicrobial protein from Pharbitis nil

    Get PDF
    An antimicrobial protein from seeds of Pharbitis nil (Pn-AMP) which shows an antifungal activity towards several agriculturally important plant pathogens has been crystallized in the presence of equimolar N-acetylglucosamine with sodium citrate as precipitant. The crystal belongs to the hexagonal space group P6(1)22 (or P6(5)22), with unit-cell parameters a = b = 29.33 (5), c = 133.44 (12) Angstrom. Native data were collected using a crystal at 100 K to a resolution of 1.78 Angstrom.open2

    Crises: Principles and Policies: With an Application to the Eurozone Crisis

    Get PDF
    Economies around the world have faced repeated crises — more frequently over the past thirty years. The fact that they have become more frequent and pervasive at the same time that we believe we have learned more about the management of the economy and as markets have seemingly improved poses a puzzle: shouldn't rational markets avoid these catastrophes, the costs of which outweigh, by an enormous amount, any benefit that might have accrued to the economy from the actions prior to the crisis that might have contributed to it? This is especially true of the large fraction of crises that can be called “debt crises,” precipitated by a country’s difficulty in repaying what it owes. The benefits of income smoothing (arising from the difference in the marginal utility of income in periods when income is low and when income is high) are overwhelmed by the social and economic costs of the ensuing crisis

    Whither Capitalism? Financial externalities and crisis

    Get PDF
    As with global warming, so with financial crises – externalities have a lot to answer for. We look at three of them. First the financial accelerator due to ‘fire sales’ of collateral assets -- a form of pecuniary externality that leads to liquidity being undervalued. Second the ‘risk- shifting’ behaviour of highly-levered financial institutions who keep the upside of risky investment while passing the downside to others thanks to limited liability. Finally, the network externality where the structure of the financial industry helps propagate shocks around the system unless this is checked by some form of circuit breaker, or ‘ring-fence’. The contrast between crisis-induced Great Recession and its aftermath of slow growth in the West and the rapid - and (so far) sustained - growth in the East suggests that successful economic progress may depend on how well these externalities are managed

    Absence of the Septum Pellucidum Associated with a Midline Fornical Nodule and Ventriculomegaly: A Report of Two Cases

    Get PDF
    We report two autopsy cases that revealed the partial absence of the septum pellucidum with ventriculomegaly. In each case, the brain showed mild dilatation of both frontal horns of the lateral ventricles, normal third and fourth ventricles and no aqueductal stenosis. The posterior portion of the septum pellucidum was absent and the fornices were fused in a single midline nodule, abnormally displaced to a caudal position and lodged in the foramina of Monro. The brain base showed no apparent abnormalities; the optic nerves were well developed. We conclude that the caudally displaced fornix in the absence of the septum pellucidum may have intermittently obstructed the foramina of Monro and induced mild ventriculomegaly

    Developmental variations in plasma leptin, leptin soluble receptor and their molar ratio in healthy infants

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Leptin and its soluble receptor (sOB-R) are important to regulation of body composition but there are no data on the developmental variations in these plasma variables and their relationship with body composition measurements,</p> <p>Methods</p> <p>Weight, length, and body composition (bone, fat and lean mass) by dual energy absorptiometry, and plasma variables were measured in healthy infants at 2, 4, 8 and 12 months.</p> <p>Results</p> <p>15 whites and 29 African Americans (21 males and 23 females) with mean birth weight 3357 +/- 45 (SEM) g and gestation of 39.3 +/- 0.17 weeks were studied. The overall Z score for weight, length and weight for length during the study were 0.00 +/- 0.15, -0.08 +/- 0.11 and 0.12 +/- 0.14 respectively. With increasing age, plasma leptin (1.0 to 18.2, median 5.5 ng/mL) and sOB-R:leptin molar ratio (10.1 to 247.4, median 59.9) were lowered (r = -0.47, p < 0.01; and r = -0.37, p < 0.05 respectively), best predicted by weight Z score and percentage of fat mass, and higher in African American and female. Presence of body composition measurements eliminated the race and gender effect on the plasma variables. Plasma sOB-R (49.5 to 173.9, median 81.3 ng/mL) did not change significantly with age and was correlated and predicted only by body composition measurements.</p> <p>Conclusion</p> <p>In healthy growing infants, plasma leptin but not sOB-R decreases with age. Gender, race and anthropometric measurements are additional physiological determinants predictive of plasma leptin and the receptor:ligand ratio. However, body composition is the only variable that can predict plasma leptin and its soluble receptor and the receptor: ligand ratio; and body composition measurements eliminated the race and gender effect on these plasma variables.</p

    Enhanced Solubility of the Support in an FDM-Based 3D Printed Structure Using Hydrogen Peroxide under Ultrasonication

    Get PDF
    Fused deposition modeling (FDM), one of the archetypal 3D printing processes, typically requires support structures matched to printed model parts that principally have undercut or overhung features. Thus, the support removal is an essential postprocessing step after the FDM process. Here, we present an efficient and rapid method to remove the support part of an FDM-manufactured product using the phenomenon of oxidative degradation of hydrogen peroxide. This mechanism was significantly effective on polyvinyl alcohol (PVA), which has been widely used as a support material in the FDM process. Compared to water, hydrogen peroxide provided a two times faster dissolution rate of the PVA material. This could be increased another two times by applying ultrasonication to the solvent. In addition to the rapidness, we confirmed that amount of the support residues removed was enhanced, which was essentially caused by the surface roughness of the FDM-fabricated part. Furthermore, we demonstrated that there was no deterioration with respect to the mechanical properties or shape geometries of the obtained 3D printed parts. Taken together, these results are expected to help enhance the productivity of FDM by reducing the postprocessing time and to allow the removal of complicated and fine support structures, thereby improving the design capability of the FDM technique

    Abnormal Vestibular Evoked Myogenic Potentials in Medial Medullary Infarction

    Get PDF
    Background The medial vestibulospinal tract (MVST), which descends in the medial longitudinal fasciculus (MLF), may mediate the vestibular evoked myogenic potentials (VEMPs) in the contracting sternocleidomastoid muscle. We report herein abnormal VEMPs in a patient with medial medullary infarction (MMI) that appeared to involve the MLF. Case Report A patient with infarction involving the right medial medulla showed decreased p13-n23 amplitude and increased p13/n23 latencies of the VEMPs on the right side. These abnormal VEMPs recorded in all MMI patient support the theory that VEMPs are mediated by the MVST contained within the MLF. Conclusions VEMPs may represent a valuable tool for investigating vestibular dysfunction originating from the saccule, even ill patients with central vestibulopathies, which is not readily defined by conventional vestibular function tests. J Clin Neurol 2009;5:101-103This study was supported by a grant of the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (A080750). The authors thank Jong-Hee Lee for experimental assistance.Kim JS, 2005, NEUROLOGY, V65, P1294Welgampola MS, 2005, NEUROLOGY, V64, P1682Newlands SD, 2003, J COMP NEUROL, V466, P31, DOI 10.1002/cne.10876Chen CH, 2003, LARYNGOSCOPE, V113, P990Murofushi T, 1999, ARCH OTOLARYNGOL, V125, P660Murofushi T, 1996, ARCH OTOLARYNGOL, V122, P845WILSON VJ, 1995, J VESTIBUL RES-EQUIL, V5, P147MUROFUSHI T, 1995, EXP BRAIN RES, V103, P174ROBERTSON DD, 1995, J OTOLARYNGOL, V24, P3COLEBATCH JG, 1994, J NEUROL NEUROSUR PS, V57, P190COLEBATCH JG, 1992, NEUROLOGY, V42, P1635AKAIKE T, 1983, BRAIN RES, V259, P217FERNANDEZ C, 1976, J NEUROPHYSIOL, V39, P970POMPEIANO O, 1957, ARCH ITAL BIOL, V95, P166

    Using Nutrition for Intervention and Prevention against Environmental Chemical Toxicity and Associated Diseases

    Get PDF
    BACKGROUND: Nutrition and lifestyle are well-defined modulators of chronic diseases. Poor dietary habits (such as high intake of processed foods rich in fat and low intake of fruits and vegetables), as well as a sedentary lifestyle clearly contribute to today’s compromised quality of life in the United States. It is becoming increasingly clear that nutrition can modulate the toxicity of environmental pollutants. OBJECTIVES: Our goal in this commentary is to discuss the recommendation that nutrition should be considered a necessary variable in the study of human disease associated with exposure to environmental pollutants. DISCUSSION: Certain diets can contribute to compromised health by being a source of exposure to environmental toxic pollutants. Many of these pollutants are fat soluble, and thus fatty foods often contain higher levels of persistent organics than does vegetable matter. Nutrition can dictate the lipid milieu, oxidative stress, and antioxidant status within cells. The modulation of these parameters by an individual’s nutritional status may have profound affects on biological processes, and in turn influence the effects of environmental pollutants to cause disease or dysfunction. For example, potential adverse health effects associated with exposure to polychlorinated biphenyls may increase as a result of ingestion of certain dietary fats, whereas ingestion of fruits and vegetables, rich in antioxidant and anti-inflammatory nutrients or bioactive compounds, may provide protection. CONCLUSIONS: We recommend that future directions in environmental health research explore this nutritional paradigm that incorporates a consideration of the relationships between nutrition and lifestyle, exposure to environmental toxicants, and disease. Nutritional interventions may provide the most sensible means to develop primary prevention strategies of diseases associated with many environmental toxic insults
    corecore