Dynamical Fine Tuning in Brane Inflation

We investigate a novel mechanism of dynamical tuning of a flat potential in the open string landscape within the context of warped brane-antibrane inflation in type IIB string theory. Because of competing effects between interactions with the moduli stabilizing D7-branes in the warped throat and anti-D3-branes at the tip, a stack of branes gives rise to a local minimum of the potential, holding the branes high up in the throat. As branes successively tunnel out of the local minimum to the bottom of the throat the potential barrier becomes lower and is eventually replaced by a flat inflection point, around which the remaining branes easily inflate. This dynamical flattening of the inflaton potential reduces the need to fine tune the potential by hand, and also leads to successful inflation for a larger range of inflaton initial conditions, due to trapping in the local minimum.Comment: 23 pages, 9 figures. v2: Updated D3-dependence in potential, small changes to numerical result

Amplitude Zeros in W±ZW^\pm Z Production

We demonstrate that the Standard Model amplitude for $f_1 \bar f_2 \rightarrow W^\pm Z$ at the Born-level exhibits an approximate zero located at $\cos\theta = (g^{f_1}_{-} + g^{f_2}_{-}) / (g^{f_1}_{-} - g^{f_2}_{-})$ at high energies, where the $g^{f_i}_{-}$ ($i=1,2$) are the left-handed couplings of the $Z$-boson to fermions and $\theta$ is the center of mass scattering angle of the $W$-boson. The approximate zero is the combined result of an exact zero in the dominant helicity amplitudes ${\cal M}(\pm,\mp)$ and strong gauge cancelations in the remaining amplitudes. For non-standard $WWZ$ couplings these cancelations no longer occur and the approximate amplitude zero is eliminated.Comment: 11 pages, 4 figures submitted separately as uuencoded tar-ed postscript files, FSU-HEP-940307, UCD-94-

Focused Screening Identifies Different Sensitivities of Human TET Oxygenases to the Oncometabolite 2-Hydroxyglutarate

Ten-eleven translocation enzymes (TETs) are Fe(II)/2-oxoglutarate (2OG) oxygenases that catalyze the sequential oxidation of 5-methylcytosine to 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine in eukaryotic DNA. Despite their roles in epigenetic regulation, there is a lack of reported TET inhibitors. The extent to which 2OG oxygenase inhibitors, including clinically used inhibitors and oncometabolites, modulate DNA modifications via TETs has been unclear. Here, we report studies on human TET1–3 inhibition by a set of 2OG oxygenase-focused inhibitors, employing both enzyme-based and cellular assays. Most inhibitors manifested similar potencies for TET1–3 and caused increases in cellular 5hmC levels. (R)-2-Hydroxyglutarate, an oncometabolite elevated in isocitrate dehydrogenase mutant cancer cells, showed different degrees of inhibition, with TET1 being less potently inhibited than TET3 and TET2, potentially reflecting the proposed role of TET2 mutations in tumorigenesis. The results highlight the tractability of TETs as drug targets and provide starting points for selective inhibitor design

Updated Atomic Data and Calculations for X-ray Spectroscopy

We describe the latest release of AtomDB, version 2.0.2, a database of atomic data and a plasma modeling code with a focus on X-ray astronomy. This release includes several major updates to the fundamental atomic structure and process data held within AtomDB, incorporating new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions, including the iron L-shell ions from Fe$^{+16}$ to Fe$^{+23}$ and all of the hydrogen- and helium-like sequences. We also describe some of the effects that these changes have on calculated emission and diagnostic line ratios, such as changes in the temperature implied by the He-like G-ratios of up to a factor of 2.Comment: Submitted to ApJ, 12 pages, 9 figure

Structure of human RECQ1 helicase: identification of a putative DNA strand-separation pin

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Time to improve informed consent for dialysis: an international perspective

The literature reveals that current nephrology practice in obtaining informed consent for dialysis falls short of ethical and legal requirements. Meeting these requirements represents a significant challenge, especially because the benefits and risks of dialysis have shifted significantly with the growing number of older, comorbid patients. The importance of informed consent for dialysis is heightened by several concerns, including: (1) the proportion of predialysis patients and patients on dialysis who lack capacity in decision making and (2) whether older, comorbid, and frail patients understand their poor prognosis and the full implications to their independence and functional status of being on dialysis. This article outlines the ethical and legal requirements for a valid informed consent to dialysis: (1) the patient was competent, (2) the consent was made voluntarily, and (3) the patient was given sufficient information in an understandable manner to make the decision. It then considers the application of these requirements to practice across different countries. In the process of informed consent, the law requires a discussion by the physician of the material risks associated with dialysis and alternative options. We argue that, legally and ethically, this discussion should include both the anticipated trajectory of the illness and the effect on the life of the patient with particular regard to the outcomes most important to the individual. In addition, a discussion should occur about the option of a conservative, nondialysis pathway. These requirements ensure that the ethical principle of respect for patient autonomy is honored in the context of dialysis. Nephrologists need to be open to, comfortable with, and skillful in communicating this information. From these clear, open, ethically, and legally valid consent discussions, a significant dividend will hopefully flow for patients, families, and nephrologists alike

Industrial constructions of publics and public knowledge: a qualitative investigation of practice in the UK chemicals industry

This is a post print version of the article. The official published version can be obtained from the link below - © 2007 by SAGE PublicationsWhile the rhetoric of public engagement is increasingly commonplace within industry, there has been little research that examines how lay knowledge is conceptualized and whether it is really used within companies. Using the chemicals sector as an example, this paper explores how companies conceive of publics and "public knowledge," and how this relates to modes of engagement/communication with them. Drawing on qualitative empirical research in four companies, we demonstrate that the public for industry are primarily conceived as "consumers" and "neighbours," having concerns that should be allayed rather than as groups with knowledge meriting engagement. We conclude by highlighting the dissonance between current advocacy of engagement and the discourses and practices prevalent within industry, and highlight the need for more realistic strategies for industry/public engagement.Funding was received from the ESRC Science in Society Programme

An Approach to the Cosmological Constant Problem(s)

We propose an approach to explaining why naive large quantum fluctuations are not the right estimate for the cosmological constant. We argue that the universe is in a superposition of many vacua, in such a way that the resulting fluctuations are suppressed by level repulsion to a very small value. The approach combines several aspects of string theory and the early history of the universe, and is only valid if several assumptions hold true. The approach may also explain why the effective cosmological constant reamins small as the universe evolves though several phase transitions. It provides a non-anthropic mechansim leading to a small, non-zero cosmological constant.Comment: Talk given at Rencontres de Moriond, 2004 by G.L. Kan

A latent class analysis of young women’s co-occurring health risks in urban informal settlements in Durban, South Africa

This is the final version. Available on open access from Elsevier via the DOI in this recordAvailability of data and material (data transparency): Data are available in a public, open access repository. De-identified data sets for the project are available from http://medat.samrc.ac.za/index.php/catalog/WW managed by the South African Medical Research Council.In South Africa, substance use, violence, and HIV risk disproportionately affect young poor Black women. Few studies have explicitly measured the co-occurrence of these health risks or the impact on mental health and wellbeing for this population. To this aim, we use a person-centred approach to explore the clustering of health risks among young Black women from urban informal settlements in Durban, South Africa, enrolled in an intervention trial. Latent class analysis identified three health risk subgroups with increasing levels of health risk co-occurrence: while all three subgroups had high rates of emotional/economic intimate partner violence, they differed in their levels of the other health risks, with one (“lower-risk”) subgroup defined by experiencing violence against women (VAW), another by the co-occurrence of VAW with problematic alcohol use (i.e. “mid-risk”), and the last (“high-risk”) subgroup by the co-occurrence of VAW, problematic alcohol use and sexual risk behaviour. Descriptive analyses showed that lower education and food insecurity were associated with greater health risk co-occurrence and that this in turn was associated with increased chances of depression and suicidal ideation. Between subgroup differences persisted over time - after two years, the chances of experiencing violence, problematic alcohol use, transactional sex and depression remained elevated for the women who initially experienced more health risks. Persistent yet differing levels of risk suggest the need for urgent structural interventions that address these health risks synergistically while taking account of individual differing primary and secondary prevention needs. Our analyses highlight that social epidemics such as poverty, racism and gender inequality play into the production of poor health outcomes, including poor mental health. These are the underlying structural issues that need to be addressed in order to protect women’s health and reduce harm.UKR

Quantum Gravity in Everyday Life: General Relativity as an Effective Field Theory

This article is meant as a summary and introduction to the ideas of effective field theory as applied to gravitational systems. Contents: 1. Introduction 2. Effective Field Theories 3. Low-Energy Quantum Gravity 4. Explicit Quantum Calculations 5. ConclusionsComment: 56 pages, 2 figures, JHEP style, Invited review to appear in Living Reviews of Relativit