119 research outputs found
Young men's suicidal behavior, depression, crime, and substance use risks linked to childhood teasing
No full textConnecting scattering, monodromy, and MST's renormalized angular momentum for the Teukolsky equation in Kerr spacetime
No full textThe Teukolsky equation describes perturbations of Kerr spacetime and is central to the study of rotating black holes and gravitational waves. In the frequency domain, the Teukolsky equation separates into radial and angular ordinary differential equations. Mano, Suzuki, and Takasugi (MST) found semi-analytic solutions to the homogeneous radial Teukolsky equation in terms of series of analytic special functions. The MST expansions hinge on an auxiliary parameter known as the renormalized angular momentum ν, which one must calculate to ensure the convergence of these series solutions. In this work, we present a method for calculating ν via monodromy eigenvalues, which capture the behavior of ordinary differential equations and their solutions in the complex domain near their singular points. We directly relate the monodromy data of the radial Teukolsky equation to the parameter ν and provide a numerical scheme for calculating ν based on monodromy. With this method we evaluate ν in different regions of parameter space and analyze the numerical stability of this approach. We also highlight how, through ν, monodromy data are linked to scattering amplitudes for generic (linear) perturbations of Kerr spacetime.The material is based upon work supported by NASA under award number 80GSFC21M0002. This work was also supported by NSF Grant No. PHY-1806447 to the University of North Carolina–Chapel Hill. The author also thanks A.C. Ottiwell, B. Wardell, M. Casals, and C.R. Evans for useful discussions. This work makes use of the Black Hole Perturbation Toolkit.https://iopscience.iop.org/article/10.1088/1361-6382/adf0d
Immunocompetence in Hydra. Epithelial cells recognize self-nonself and react against it
No full textThe evolution of effective immunologic defense mechanisms in multicellular organisms involves the ability of host cells to distinguish betweeen self and nonself and to react appropriately to eliminate foreign tissue. By producing interspecies grafts we have obtained evidence that immunorecognition followed by incompatibility reactions occur in Hydra. Our results demonstrate that epithelial cells of Hydra recognize and phagocytose foreign hydra cells, indicating that they are the effector cells in the incompatibility reactions. This observation is consistent with the idea that immunocompetence appeared early in the evolution of multicellular organisms
Assessment of child problem behaviors by multiple informants: a longitudinal study from preschool to school entry
No full textOn price inflation
No full textThis thesis seeks to analyse price inflation under oligopoly capitalism. Its central argument is that under oligopoly capitalism, price inflation is a structural phenomenon. For a greater understanding of that phenomenon, the adoption of the inter-industrial approach for its analysis seems essential. According to this approach, price inflation can be initiated in a single industry or in an industry group. The initiating factor may be an increase in the mark-up, an increase in the money wage rate or an increase in the foreign currency price of an imported input. It can also be initiated by devaluation. The input-output matrix, the core of the economic system, is the key to the transmission of inflationary impulses (in the form of higher unit cost) from one industry to another. Real wage resistance, rigid mark-up resistance, and rigid foreign resistance do no more than perpetuate or worsen the inflationary experience. The inflationary process itself has a dual role to play. It acts as a mechanism for shifting income distribution in favour of one section of the society against another and as a mechanism for changing the price structure.The author argues that the abandonment of the macroeconomic approach to the analysis of price inflation and its replacement by the inter-industrial approach is the first step for serious analysis of that structural phenomenon
Community social support as a protective factor against suicide
No full textBy studying differences in suicide rates among different geographical regions one may identify factors connected to suicidal behaviour on a regional level. Many studies have focused on risk factors, whereas less is known about protective factors, such as social support. Using suicide rates and data from the European Social Survey (ESS) we explore the association between regional level social support indicator and suicide rates in 23 European countries in 2012. Linear multiple regression analyses using region as the unit of analysis revealed inverse relationships between mean respondent valuing of social support and suicide rates for both genders, with some indication of a stronger relationship among men. Social support may have a protective effect against suicide on a regional level. Thus, increasing social support could be an effective focus of preventive activities, resulting in lowering suicide rates, with greater expected results among men.No Full Tex
The minority of King James V, 1513-1528
No full textThe thesis is a detailed study of Scottish central government
institutions, personnel and policies during the long and politically complex
minority of James V 1513-1528. Research has been undertaken principally in
the records of the Lords of Council which have never been published nor
examined intensively for this period. Documents from various family
collections further supplement the wide range of record sources which have
been published, particularly the Letters and Papers..., and State Papers of
Henry VIII. The contribution ma4g by contemporary and later chroniclers has
also been examined with the conclusion that their contributions are of some
value, provided that due recognition is given to their motivation for writing
history.
Examination of the role and influence of faction at Court, pro-English
against pro-French, has broadened the scope of the thesis to include
discussion of the wider themes of Scottish foreign policy in the early
sixteenth century. Consideration is also given to the effect of the
unprecedented opportunities presented to England and France for interference
through the rival claims to authority made by Queen Margaret Tudor, mother of
James V, and John, Duke of Albany, the nearest male relative of the young
King. The complex political machinations following Albany's final departure
in 1524, which led to the domination of the Scottish government by Archibald,
6th Earl of Angus, during the final years of James V's minority are discussed
at length.
The conclusion is that the development of royal autocracy was hindered
by the King's youth and that this minority contributes to the evidence that,
in general, minorities acted as a safety-valve in the development of Scottish
government, preserving a balance between the interests of crown and magnates.
Nevertheless, there was a genuine desire shown by the magnates to have a
Governor able to act as if he was a-king of full age because of the advantage
such a position could bring, especially in foreign relations. Government did
not stagnate because there was no adult king
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Molecular pharmacology of an insect GABA receptor
No full textCys-loop receptors are ligand-gated ion channels that are involved in fast synaptic neurotransmission in the central and peripheral nervous system. The Cys-loop receptor RDL (‘resistant to dieldrin’) is a GABA-gated chloride channel from Drosophila melanogaster and is a major target site for insecticides. The aim of this dissertation was to characterise RDL receptors with particular focus on the agonist binding site.
To assess the potency of a range of GABA analogues on RDL receptors, I expressed receptors in Xenopus oocytes and used voltage-clamp electrophysiology to detect receptor responses. I carried out computational modelling of these analogues to determine the dipole separation distances and atomic charges. Computational calculations and functional experiments revealed that agonists require a charged ammonium and an anionic centre, with the most potent agonists having a dipole separation distance of ~5 Å. I made a homology model of the extracellular domain of RDL and docked the active analogues into the putative binding site. I then conducted mutagenesis studies to test the accuracy of this model. Functional data from mutagenesis studies broadly support the location of GABA within this model. This model may be useful for further structure−activity studies and rational drug design.
Natural compounds from the traditional Chinese medicine ‘Ginkgo biloba’ (ginkgolide A, ginkgolide B and bilobalide) have potent insecticidal properties and are similar in structure to picrotoxin. I tested the effect of these compounds on RDL receptor function using voltage-clamp electrophysiology. All compounds were found to inhibit RDL receptor function. I probed the binding site of these compounds using site-directed mutagenesis and electrophysiology. Mutations to the 2'A and 6'T channel-lining (M2) residues greatly reduced the potency of these compounds. I then made a homology model of the transmembrane domain of RDL and docked these compounds into the channel. Compounds docked into the channel pore close to the 2' and 6' channel-lining residues and H-bonding interactions were detected at these locations. Ginkgolides are therefore antagonists of RDL receptors, binding in the channel close to the 2' and 6' residues and this may be the mechanism underlying their potent insecticidal properties.
The 5-HT3 receptor is a member of the Cys-loop receptor family and shows homology to RDL receptors. To explore different techniques for studying Cys-loop receptor function I assessed the functionality of two brain derived transcripts of the 5-HT3B subunit (Br1 and Br2) using single-channel electrophysiology and a fluorometric assay. Receptors containing Br1 were found to have a conductance identical to the 5-HT3B subunit whilst Br2 receptors were found not to be expressed. This finding has implications for 5-HT3 brain signalling, in which Br1 may play an important role.
In conclusion, work here has described how agonists bind to and activate RDL GABA receptors and I have identified a candidate mechanism for the potent insecticidal properties of Ginkgo biloba extracts. I have also confirmed that 5-HT3 receptor brain transcript Br1 forms functional channels with similar properties to the 5-HT3B subunit
Searching speeds and the energetic feasibility of an obligate whale-scavenging fish
No full textTwo recently published models reach opposite conclusions on the energetic feasibility of a scavenging fish that specialises oil whale carcasses. We argue that the key difference between these models lies in their estimate of the likely searching speed of such a hypothetical scavenger. Neither of the previous models considers that although faster searching will allow food sites to be found more quickly, it will also reduce the time between meals that the fish can survive on its reserves. Hence, we present a novel model that encapsulates this trade-off, and use this model to predict the optimal searching speed for Such a hypothetical scavenger. The model predicts that the optimal speed should increase with mass and be in the range 0.1-0.2 m s(-1) for fish of the range of sizes found for the ubiquitous grenadier Coryphaenoides armatus. These values accord with most estimates of the swimming speeds for this species. Hence, we conclude that rejection of a whale-carcass feeding specialist fish on energetic grounds is premature. Although, we see no reason to dismiss Such a specialist oil energetic grounds, we argue that such a fish will be unlikely oil ecological grounds, although a deep-sea fish that gathered much of its energy from scavenging at relatively large food packages oil the ocean floor should be feasible
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