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"Ramsey, J."
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The electroweak phase transition: a collider target
A
bstract
Determining the thermal history of electroweak symmetry breaking (EWSB) is an important challenge for particle physics and cosmology. Lattice simulations indicate that EWSB in the Standard Model (SM) occurs through a crossover transition, while the presence of new physics beyond the SM could alter this thermal history. The occurrence of a first order EWSB transition would be particularly interesting, providing the needed pre-conditions for generation of the cosmic matter-antimatter asymmetry and sources for potentially observable gravitational radiation. I provide simple, generic arguments that if such an alternate thermal history exists, the new particles involved cannot be too heavy with respect to the SM electroweak temperature, nor can they interact too feebly with the SM Higgs boson. These arguments do not rely on the decoupling limit. I derive corresponding quantitative expectations for masses and interaction strengths which imply that their effects could in principle be observed (or ruled out) by prospective next generation high energy colliders. The simple, generic arguments provide a quantitative, parametric understanding of results obtained in a wide range of explicit model studies; relate them explicitly to the electroweak temperature; and delineate broad contours of collider phenomenology pertaining to a non-standard history of EWSB.
Journal Article
Fragments of the Histories ; Letters to Caesar
\"Sallust, Gaius Sallustius Crispus (86-35 BCE), a Sabine from Amiternum, acted as tribune against Cicero and Milo in 52, joined Caesar after being expelled from the Senate in 50, was restored to the Senate by Caesar and took part in his African campaign as praetor in 46, and was then appointed governor of New Africa (Numidia). Upon his return to Rome he narrowly escaped conviction for malfeasance in office, retired from public life, and took up historiography. Sallust's last work, the annalistic Histories in five books, is much more expansive than his monographs on Catiline and Jugurtha (LCL 116), treating the whole of Roman history at home and abroad in the post-Sullan age. Although fragmentary, it provides invaluable information and insight about a crucial period of history spanning the period from 78 to around 67 BCE. Although Sallust is decidedly unsubtle and partisan in analyzing people and events, his works are important and significantly influenced later historians, notably Tacitus. Taking Thucydides as his model but building on Roman stylistic and rhetorical traditions, Sallust achieved a distinctive style, concentrated and arresting; lively characterizations, especially in the speeches; and skill at using particular episodes to illustrate large general themes.\"--Publisher description.
Book
Differential in Vitro Biological Action, Coregulator Interactions, and Molecular Dynamic Analysis of Bisphenol A (BPA), BPAF, and BPS Ligand–ERα Complexes
Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) that might be harmful to human health. Recently, there has been widespread usage of bisphenol chemicals (BPs), such as bisphenol AF (BPAF) and bisphenol S (BPS), as replacements for BPA. However, the potential biological actions, toxicity, and the molecular mechanism of these compounds are still poorly understood.
Our objective was to examine the estrogenic effects of BPA, BPAF, and BPS and the molecular mechanisms of action in the estrogen receptor alpha (ERα) complex.
cell models were used to compare the estrogenic effects of BPA, BPAF, and BPS to estrogen. Microarray Assay for Real-Time Coregulator-Nuclear receptor Interaction (MARCoNI) analysis was used to identify coregulators of BPA, BPAF, and BPS, and molecular dynamic (MD) simulations were used to determine the compounds binding in the ERα complex.
We demonstrated that BPA and BPAF have agonistic activity for both ERα and ERβ, but BPS has ERα-selective specificity. We concluded that coregulators were differentially recruited in the presence of BPA, BPAF, or BPS. Interestingly, BPS recruited more corepressors when compared to BPA and BPAF. From a series of MD analysis, we concluded that BPA, BPAF, and BPS can bind to the ER-ligand-binding domain with differing energetics and conformations. In addition, the binding surface of coregulator interactions on ERα was characterized for the BPA, BPAF, and BPS complexes.
These findings further our understanding of the molecular mechanisms of EDCs, such as BPs, in ER-mediated transcriptional activation, biological activity, and their effects on physiological functions in human health. https://doi.org/10.1289/EHP2505.
Journal Article
The war with Catiline ; The war with Jugurtha
\"Sallust, Gaius Sallustius Crispus (86-35 BCE), a Sabine from Amiternum, acted against Cicero and Milo as tribune in 52, joined Caesar after being expelled from the Senate in 50, was restored to the senate by Caesar and took part in his African campaign as praetor in 46, and was then appointed governor of New Africa (Numidia). Upon his return to Rome he narrowly escaped conviction for malfeasance in office, retired from public life, and took up historiography. Sallust's two extant monographs take as their theme the moral and political decline of Rome, one on the conspiracy of Catiline and the other on the war with Jugurtha. Although Sallust is decidedly unsubtle and partisan in analyzing people and events, his works are important and significantly influenced later historians, notably Tacitus. Taking Thucydides as his model but building on Roman stylistic and rhetorical traditions, Sallust achieved a distinctive style, concentrated and arresting; lively characterizations, especially in the speeches; and skill at using particular episodes to illustrate large general themes\"--Publisher website.
Book
Enhanced nanochannel translocation and localization of genomic DNA molecules using three-dimensional nanofunnels
The ability to precisely control the transport of single DNA molecules through a nanoscale channel is critical to DNA sequencing and mapping technologies that are currently under development. Here we show how the electrokinetically driven introduction of DNA molecules into a nanochannel is facilitated by incorporating a three-dimensional nanofunnel at the nanochannel entrance. Individual DNA molecules are imaged as they attempt to overcome the entropic barrier to nanochannel entry through nanofunnels with various shapes. Theoretical modeling of this behavior reveals the pushing and pulling forces that result in up to a 30-fold reduction in the threshold electric field needed to initiate nanochannel entry. In some cases, DNA molecules are stably trapped and axially positioned within a nanofunnel at sub-threshold electric field strengths, suggesting the utility of nanofunnels as force spectroscopy tools. These applications illustrate the benefit of finely tuning nanoscale conduit geometries, which can be designed using the theoretical model developed here.
Forcing a DNA molecule into a nanoscale channel requires overcoming the free energy barrier associated with confinement. Here, the authors show that DNA injected through a funnel-shaped entrance more efficiently enters the nanochannel, thanks to facilitating forces generated by the nanofunnel geometry.
Journal Article
Tunneling potentials for the tunneling action: gauge invariance
A
bstract
We formulate a procedure to obtain a gauge-invariant tunneling rate at zero temperature using the recently developed tunneling potential approach. This procedure relies on a consistent power counting in gauge coupling and a derivative expansion. The tunneling potential approach, while numerically more efficient than the standard bounce solution method, inherits the gauge-dependence of the latter when naïvely implemented. Using the Abelian Higgs model, we show how to obtain a tunneling rate whose residual gauge-dependence arises solely from the polynomial approximations adopted in the tunneling potential computation.
Journal Article
Distinct pathways mediate axon degeneration during apoptosis and axon-specific pruning
Neurons can activate pathways that destroy the whole cell
via
apoptosis or selectively degenerate only the axon (pruning). Both apoptosis and axon degeneration require Bax and caspases. Here we demonstrate that despite this overlap, the pathways mediating axon degeneration during apoptosis versus axon pruning are distinct. While Caspase-6 is activated in axons following nerve growth factor deprivation, microfluidic chamber experiments reveal that Caspase-6 deficiency only protects axons during axon-specific but not whole-cell (apoptotic) nerve growth factor deprivation. Strikingly, axon-selective degeneration requires the apoptotic proteins Caspase-9 and Caspase-3 but, in contrast to apoptosis, not apoptotic protease activating factor-1. Additionally, cell bodies of degenerating axons are protected from caspase activation by proteasome activity and X-linked inhibitor of apoptosis protein. Also, mature neurons restrict apoptosis but remain permissive for axon degeneration, further demonstrating the independent regulation of these two pathways. These results reveal insight into how neurons allow for precise control over apoptosis and axon-selective degeneration pathways, thereby permitting long-term plasticity without risking neurodegeneration.
Recent studies suggest that there is an overlap between neuronal apoptosis and axon-specific degeneration. Cusack and colleagues show that the caspase-dependent pathways mediating axon degeneration during apoptosis are distinct from those mediating localized axon pruning.
Journal Article
Measurement of the neutron lifetime using a magneto-gravitational trap and in situ detection
Unlike the proton, whose lifetime is longer than the age of the universe, a free neutron decays with a lifetime of about 15 minutes. Measuring the exact lifetime of neutrons is surprisingly tricky; putting them in a container and monitoring their decay can lead to errors because some neutrons will be lost owing to interactions with the container walls. To overcome this problem, Pattie et al. measured the lifetime in a trap where ultracold polarized neutrons were levitated by magnetic fields, precluding interactions with the trap walls (see the Perspective by Mumm). This more precise determination of the neutron lifetime will aid our understanding of how the first nuclei formed after the Big Bang. Science , this issue p. 627 ; see also p. 605 Ultracold polarized neutrons are levitated in a trap to measure their lifetime with reduced systematic uncertainty. The precise value of the mean neutron lifetime, τ n , plays an important role in nuclear and particle physics and cosmology. It is used to predict the ratio of protons to helium atoms in the primordial universe and to search for physics beyond the Standard Model of particle physics. We eliminated loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls. As a result of this approach and the use of an in situ neutron detector, the lifetime reported here [877.7 ± 0.7 (stat) +0.4/–0.2 (sys) seconds] does not require corrections larger than the quoted uncertainties.
Journal Article
Lavender Products Associated With Premature Thelarche and Prepubertal Gynecomastia: Case Reports and Endocrine-Disrupting Chemical Activities
Abstract
Context
Previous case reports associated prepubertal gynecomastia with lavender-containing fragrances, but there appear to be no reports of premature thelarche.
Objective
To add to a case series about lavender-fragranced product use and breast growth in children and to measure endocrine-disrupting chemical activity of essential oil components.
Design, Setting, and Patients
Patients experiencing premature thelarche or prepubertal gynecomastia with continuous exposure to lavender-fragranced products were evaluated in the pediatric endocrinology departments of two institutions. Mechanistic in vitro experiments using eight components of lavender and other essential oils were performed at National Institute of Environmental Health Sciences.
Main Outcome Measures
Case reports and in vitro estrogen and androgen receptor gene expression activities in human cell lines with essential oils.
Results
Three prepubertal girls and one boy with clinical evidence of estrogenic action and a history of continuous exposure to lavender-containing fragrances were studied. Breast growth dissipated in all patients with discontinuation of the fragranced products. Some of the components tested elicited estrogenic and antiandrogenic properties of varying degrees.
Conclusion
We report cases of premature thelarche that resolved upon cessation of lavender-containing fragrance exposure commonly used in Hispanic communities. The precise developmental basis for such conditions could be multifactorial. In vitro demonstration of estrogenic and antiandrogenic properties of essential oil components suggests essential oils in these cases could be considered a possible source and supports a possible link with idiopathic prepubertal breast development. Whether the level of lavender oil estrogenic potency is sufficient to cause these effects is unknown.
Lavender-containing fragrances may cause premature thelarche and prepubertal gynecomastia.
Journal Article