Periodic Gravitational Waves From Small Cosmic String Loops

We consider a population of small, high-velocity cosmic string loops. We assume the typical length of these loops is determined by the gravitational radiation scale and use the results of \cite{Polchinski:2007rg} which pointed out their highly relativistic nature. A study of the gravitational wave emission from such a population is carried out. The large Lorentz boost involved causes the lowest harmonics of the loops to fall within the frequency band of the LIGO detector. Due to this feature the gravitational waves emitted by such loops can be detected in a periodic search rather than in burst or stochastic analysis. It is shown that, for interesting values of the string tension (10^{-10}\lsim G\mu\lsim 10^{-8}) the detector can observe loops at reasonably high redshifts and that detection is, in principle, possible. We compute the number of expected observations produced by such a process. For a 10 hour search we find that this number is of order $O(10^{-4})$. This is a consequence of the low effective number density of the loops traveling along the line of sight. However, small probabilities of reconnection and longer observation times can improve the result.Comment: 1+15 pages, 7 figure

Solar system constraints on Rindler acceleration

We discuss the classical tests of general relativity in the presence of Rindler acceleration. Among these tests the perihelion shifts give the tightest constraints and indicate that the Pioneer anomaly cannot be caused by a universal solar system Rindler acceleration. We address potential caveats for massive test-objects. Our tightest bound on Rindler acceleration that comes with no caveats is derived from radar echo delay and yields |a|<3nm/s^2.Comment: 7 pages, v2: minor changes, added references, v3: corrected typos, extended Table 1, corrected bound on measurement of gravitational redshif

The Impact of Practicing Open- vs. Closed-Skill Sports on Executive Functions: A Meta-Analytic and Systematic Review with a Focus on Characteristics of Sports

Exercise modes can be categorized based on the skills required (open vs. closed skills), which implicates various demands on cognitive skills, especially executive functions (EFs). Thus, their practice may have varying effects on EFs. There is a lack of detailed analysis of cognitive requirements and suitable classification of sports. It is hypothesized that the amount and type of cognitive requirements of sports lead to small effect sizes when comparing open-skill exercising (OSE) and closed-skill exercising (CSE) athletes. The current meta-analysis evaluates the variances in EFs skills caused by particular sport modes. Four research databases (Web of Science, PubMed, ScienceDirect, PsychINFO) were searched for cross-sectional studies in which the authors compare the performance in EF tasks of OSE and CSE athletes. Risk of bias assessment was conducted using funnel plots and two reviewer selection process (overall and subgroup analysis; low risk of publication and selection bias). A total of 19 studies were included, revealing an overall effect size of Hedge’s g = 0.174 ( p = 0.157), favoring OSE for the development of EFs. The subgroup analysis revealed the effects for the subdomains of EFs (cognitive flexibility: Hedge’s g = 0.210 > inhibitory control: Hedge’s g = 0.191 > working memory: Hedge’s g = 0.138; p > 0.05), which could be characterized as low to moderate. The hypothesis that studies with the smallest effect sizes compare sport modes with similar cognitive demands was rejected. The paper discusses the differentiation of sports into OSE and CSE and presents new approaches for their categorization

EGFR Expression in HER2-Driven Breast Cancer Cells

The epidermal growth factor receptor HER2 is overexpressed in 20% of breast cancer cases. HER2 is an orphan receptor that is activated ligand-independently by homodimerization. In addition, HER2 is able to heterodimerize with EGFR, HER3, and HER4. Heterodimerization has been proposed as a mechanism of resistance to therapy for HER2 overexpressing breast cancer. Here, a method is presented for the simultaneous detection of individual EGFR and HER2 receptors in the plasma membrane of breast cancer cells via specific labeling with quantum dot nanoparticles (QDs). Correlative fluorescence microscopy and liquid phase electron microscopy were used to analyze the plasma membrane expression levels of both receptors in individual intact cells. Fluorescent single-cell analysis of SKBR3 breast cancer cells dual-labeled for EGFR and HER2 revealed a heterogeneous expression for receptors within both the cell population as well as within individual cells. Subsequent electron microscopy of individual cells allowed the determination of individual receptors label distributions. QD-labeled EGFR was observed with a surface density of (0.5–5) × 101 QDs/µm2, whereas labeled HER2 expression was higher ranging from (2–10) × 102 QDs/µm2. Although most SKBR3 cells expressed low levels of EGFR, an enrichment was observed at large plasma membrane protrusions, and amongst a newly discovered cellular subpopulation termed EGFR-enriched cells

EGFR Expression in HER2-Driven Breast Cancer Cells

The epidermal growth factor receptor HER2 is overexpressed in 20% of breast cancer cases. HER2 is an orphan receptor that is activated ligand-independently by homodimerization. In addition, HER2 is able to heterodimerize with EGFR, HER3, and HER4. Heterodimerization has been proposed as a mechanism of resistance to therapy for HER2 overexpressing breast cancer. Here, a method is presented for the simultaneous detection of individual EGFR and HER2 receptors in the plasma membrane of breast cancer cells via specific labeling with quantum dot nanoparticles (QDs). Correlative fluorescence microscopy and liquid phase electron microscopy were used to analyze the plasma membrane expression levels of both receptors in individual intact cells. Fluorescent single-cell analysis of SKBR3 breast cancer cells dual-labeled for EGFR and HER2 revealed a heterogeneous expression for receptors within both the cell population as well as within individual cells. Subsequent electron microscopy of individual cells allowed the determination of individual receptors label distributions. QD-labeled EGFR was observed with a surface density of (0.5–5) × 101 QDs/µm2 , whereas labeled HER2 expression was higher ranging from (2–10) × 102 QDs/µm2 . Although most SKBR3 cells expressed low levels of EGFR, an enrichment was observed at large plasma membrane protrusions, and amongst a newly discovered cellular subpopulation termed EGFR-enriched cells

Median Nerve Palsy following Elastic Stable Intramedullary Nailing of a Monteggia Fracture: An Unusual Case and Review of the Literature

Monteggia fractures are rare in children, and subtle radial head dislocations, with minor plastic deformation of the ulna, may be missed in up to a third of cases. Complications of Monteggia fractures-dislocations include persistent radial head dislocation, forearm deformity, elbow stiffness, and nerve palsies at the time of presentation. An unusual case of median nerve palsy following elastic stable intramedullary nailing of a type I Monteggia lesion in a 6-year-old girl is presented, and we highlight that, although most nerve palsies associated with a Monteggia fracture-dislocations are treated expectantly in children, early intervention here probably provided the best outcome

Improved radiative corrections for (e,e'p) experiments - A novel approach to multi-photon bremsstrahlung

Radiative processes lead to important corrections to (e,e'p) experiments. While radiative corrections can be calculated exactly in QED and to a good accuracy also including hadronic corrections, these corrections cannot be included into data analyses to arbitrary orders exactly. Nevertheless consideration of multi-photon bremsstrahlung above the low-energy cut-off is important for many (e,e'p) experiments. To date, higher-order bremsstrahlung effects concerning electron scattering experiments have been implemented approximately by employing the soft-photon approximation (SPA). In this paper we propose a novel approach to multi-photon emission which partially removes the SPA from (e,e'p) experiments. In this combined approach one hard photon is treated exactly; and additional softer bremsstrahlung photons are taken into account resorting to the soft-photon approximation. This partial removal of the soft-photon approximation is shown to be relevant for the missing-energy distribution for several kinematic settings at MAMI and TJNAF energies.Comment: 10 pages, 21 figure

Improved radiative corrections and proton charge form factor from the Rosenbluth separation technique

We investigate whether the apparent discrepancy between proton electric form factor from measurements using the Rosenbluth separation technique and polarization transfer method is due to the standard approximations employed in radiative correction procedures. Inaccuracies due to both the peaking approximation and the soft-photon approximation have been removed in our simulation approach. In contrast to results from (e,e'p) experiments, we find them in this case to be too small to explain the discrepancy.Comment: 6 pages, 3 figure

Higgs plus jet production in bottom quark annihilation at next-to-leading order

The cross section for Higgs+jet production in bottom quark annihilation is calculated through NLO QCD. The five-flavour scheme is used to derive this contribution to the Higgs+jet production cross section which becomes numerically important in the MSSM for large values of tan(beta). We present numerical results for a proton collider with 14 TeV center-of-mass energy. The NLO matrix elements for d(sigma)/d(pT) are then combined with the total inclusive cross section in order to derive the integrated cross section with a maximum cut on pT at next-to-next-to-leading order.Comment: 11 pages, 7 figure

Vacuum Energy from an Extra Dimension with UV/IR Connection

We propose a lower limit on the size of a single discrete gravitational extra dimension in the context of an effective field theory for massive gravitons. The limit arises in this setup from the requirement that the Casimir energy density of quantum fields is in agreement with the observed dark energy density of the universe. The Casimir energy densities can be exponentially suppressed to an almost arbitrarily small value by the masses of heavy bulk fields, thereby allowing a tiny size of the extra dimension. This suppression is only restricted by the strong coupling scale of the theory, which is known to be related to the compactification scale via an UV/IR connection for local gravitational theory spaces. We thus obtain an upper limit on the compactification scale of the discrete gravitational extra dimension in the range 10^7 GeV...10^12 GeV, while the strong coupling scale is by a factor 10^2 larger than the compactification scale. We also comment on a possible cancelation of the gravitational contribution to the quantum effective potential.Comment: 13 pages, 2 figures, references added and update