Simulations of extensional flow in microrheometric devices

We present a detailed numerical study of the flow of a Newtonian fluid through microrheometric devices featuring a sudden contraction–expansion. This flow configuration is typically used to generate extensional deformations and high strain rates. The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the device is intended to be used as a microfluidic extensional rheometer. To explore this idea, we examine the effect of the contraction length, aspect ratio and Reynolds number on the flow kinematics and resulting pressure field. Analysis of the computed velocity and pressure fields show that, for typical experimental conditions used in microfluidic devices, the steady flow is highly three-dimensional with open spiraling vortical structures in the stagnant corner regions. The numerical simulations of the local kinematics and global pressure drop are in good agreement with experimental results. The device aspect ratio is shown to have a strong impact on the flow and consequently on the excess pressure drop, which is quantified in terms of the dimensionless Couette and Bagley correction factors. We suggest an approach for calculating the Bagley correction which may be especially appropriate for planar microchannels

Slepton mass-splittings as a signal of LFV at the LHC

Precise measurements of slepton mass-splittings might represent a powerful tool to probe supersymmetric (SUSY) lepton flavour violation (LFV) at the LHC. We point out that mass-splittings of the first two generations of sleptons are especially sensitive to LFV effects involving $\tau-\mu$ transitions. If these mass-splittings are LFV induced, high-energy LFV processes like the neutralino decay {\nt}_2\to\nt_1\tau^{\pm}\mu^{\mp} as well as low-energy LFV processes like $\tau\to\mu\gamma$ are unavoidable. We show that precise slepton mass-splitting measurements and LFV processes both at the high- and low-energy scales are highly complementary in the attempt to (partially) reconstruct the flavour sector of the SUSY model at work. The present study represents another proof of the synergy and interplay existing between the LHC, i.e. the {\em high-energy frontier}, and high-precision low-energy experiments, i.e. the {\em high-intensity frontier}.Comment: 11 pages, 5 figures. v2: added discussion on backgrounds, added references, version to be published on JHE

The Hubble Constant

I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give $H_0$ values of around 72-74km/s/Mpc , with typical errors of 2-3km/s/Mpc. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67-68km/s/Mpc and typical errors of 1-2km/s/Mpc. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.Comment: Extensively revised and updated since the 2007 version: accepted by Living Reviews in Relativity as a major (2014) update of LRR 10, 4, 200

The MACHO Project Large Magellanic Cloud Variable Star Inventory. VIII. The Recent Star Formation History of the LMC from the Cepheid Period Distribution

We present an analysis of the period distribution of $\sim 1800$ Cepheids in the Large Magellanic Cloud, based on data obtained by the MACHO microlensing experiment and on a previous catalogue by Payne-Gaposchkin. Using stellar evolution and pulsation models, we construct theoretical period-frequency distributions that are compared to the observations. These models reveal that a significant burst of star formation has occurred recently in the LMC ($\sim 1.15\times 10^8$ years). We also show that during the last $\sim 10^8$ years, the main center of star formation has been propagating from SE to NW along the bar. We find that the evolutionary masses of Cepheids are still smaller than pulsation masses by $\sim 7$ % and that the red edge of the Cepheid instability strip could be slightly bluer than indicated by theory. There are $\sim 600$ Cepheids with periods below $\sim 2.5$ days cannot be explained by evolution theory. We suggest that they are anomalous Cepheids; a number of these stars are double-mode Cepheids

Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers

This work was supported by the Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), grants E-26/202.974/2015 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants 229755/2013-5, Brazil. LMLB is a senior research fellow of CNPq and Faperj. NG acknowledged support from the Wellcome Trust (Trust (097377, 101873, 200208) and MRC Centre for Medical Mycology (MR/N006364/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

Rotation of planet-harbouring stars

The rotation rate of a star has important implications for the detectability, characterisation and stability of any planets that may be orbiting it. This chapter gives a brief overview of stellar rotation before describing the methods used to measure the rotation periods of planet host stars, the factors affecting the evolution of a star's rotation rate, stellar age estimates based on rotation, and an overview of the observed trends in the rotation properties of stars with planets.Comment: 16 pages, 4 figures: Invited review to appear in 'Handbook of Exoplanets', Springer Reference Works, edited by Hans J. Deeg and Juan Antonio Belmont

Successful management of bilateral orbital metastases from invasive lobular breast cancer with abemaciclib and letrozole: a case report and literature review

Breast cancer is a significant global health concern, contributing to substantial morbidity and mortality among women. Hormone receptor-positive (HR+)/HER2- negative (HER2-) breast cancer constitutes a considerable proportion of cases, and significant advancements have been made in its management. CDK4/6 inhibitors (CDK4/6is) are a new targeted therapy that has demonstrated efficacy in adjuvant, advanced and metastatic settings. The propensity of lobular breast carcinomas for estrogen-rich sites, such as periocular tissues and orbital fat, may explain their tendency for orbital metastases. Current treatment strategies for these cases are predominantly palliative, and the prognosis remains poor. This article presents a unique case of a 51-year-old female with progressive right periorbital edema, pain, and limited ocular motility. An imaging work-up showed bilateral intra and extraconal orbital infiltration, which was biopsied. The histopathologic analysis disclosed mild chronic inflammatory infiltrate with thickened fibrous tissue and moderately differentiated lobular carcinoma cells, positive for GATA3 and CK7 markers, with 100% of tumor nuclei expressing estrogen receptors (ER+). A systemic evaluation showed a multicentric nodular formation in both breasts. Further diagnostic assessments unveiled an HR+/HER2- bilateral lobular breast carcinoma with synchronous bilateral orbital metastases. Systemic treatment was initiated with abemaciclib 150mg twice daily and letrozole 2.5mg once a day. However, this regimen was interrupted due to toxicity. After two weeks, treatment was resumed with a reduced abemaciclib dose (100mg twice daily) alongside letrozole, with a reasonable tolerance. Nearly two years after the initial diagnosis of inoperable metastatic cancer, the patient remains on the same systemic treatment regimen with no signs of invasive disease. This case report is the first of a patientpresenting with bilateral orbital metastases from bilateral lobular breast cancer, showing an impressive and sustained response to a first-line treatment regimen combining abemaciclib and letrozole. A literature review on bilateral orbital metastases from breast cancer is also presented.info:eu-repo/semantics/publishedVersio

Toxicity of copaiba extracts to armyworm (Spodoptera frugiperda)

The objective of this study was to evaluate the effects of methanolic extracts from leaves, peels, seeds and pulps from fruits of Copaifera langsdorffii on Spodoptera frugiperda. Extracts derived from leaves and fruit peels were more toxic to S. frugiperda than the others. Hence, they were added to the artificial diet and used in further experiments with the second instar larvae of the insect, which presented larval growth reduction, prolonged period of development, increased mortality, and lower fertility and fecundity of adults. Lower egg viability was also observed when the insect was treated with extracts of leaves and fruit peels in the larvae stage. Moreover, when subjected to ultrastructural analysis under a scanning electron microscope, such eggs showed abnormalities in the aeropylar and micropylar regions. Both extracts also increased the excretion of protein in the insect feces and inhibited trypsin activity in the in vitro test. Consequently, C. langsdorffii presents potential to be used in the development of new products to control the fall armyworm.Key words: Copaifera langsdorffii, natural products, trypsin inhibitor, botanical insecticide

f(R) theories

Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in Relativity, Published version, Comments are welcom