507 research outputs found
Superstability of Surface Nanobubbles
Shock wave induced cavitation experiments and atomic force microscopy
measurements of flat polyamide and hydrophobized silicon surfaces immersed in
water are performed. It is shown that surface nanobubbles, present on these
surfaces, do not act as nucleation sites for cavitation bubbles, in contrast to
the expectation. This implies that surface nanobubbles are not just stable
under ambient conditions but also under enormous reduction of the liquid
pressure down to −6MPa. We denote this feature as superstability.Comment: 5 pages, 2 figure
Preferred sizes and ordering in surface nanobubble populations
Two types of homogeneous surface nanobubble populations, created by different
means, are analyzed statistically on both their sizes and spatial positions. In
the first type (created by droplet-deposition, case A) the bubble size R is
found to be distributed according to a generalized gamma law with a preferred
radius R*=20 nm. The radial distribution function shows a preferred spacing at
~5.5 R*. These characteristics do not show up in comparable Monte-Carlo
simulations of random packings of hard disks with the same size distribution
and the same density, suggesting a structuring effect in the nanobubble
formation process. The nanobubble size distribution of the second population
type (created by ethanol-water exchange, case B) is a mixture of two clearly
separated distributions, hence, with two preferred radii. The local ordering is
less significant, due to the looser packing of the nanobubbles.Comment: 5 pages, 5 figure
Event generation with SHERPA 1.1
In this paper the current release of the Monte Carlo event generator Sherpa,
version 1.1, is presented. Sherpa is a general-purpose tool for the simulation
of particle collisions at high-energy colliders. It contains a very flexible
tree-level matrix-element generator for the calculation of hard scattering
processes within the Standard Model and various new physics models. The
emission of additional QCD partons off the initial and final states is
described through a parton-shower model. To consistently combine multi-parton
matrix elements with the QCD parton cascades the approach of Catani, Krauss,
Kuhn and Webber is employed. A simple model of multiple interactions is used to
account for underlying events in hadron--hadron collisions. The fragmentation
of partons into primary hadrons is described using a phenomenological
cluster-hadronisation model. A comprehensive library for simulating tau-lepton
and hadron decays is provided. Where available form-factor models and matrix
elements are used, allowing for the inclusion of spin correlations; effects of
virtual and real QED corrections are included using the approach of Yennie,
Frautschi and Suura.Comment: 47 pages, 21 figure
In Utero Drug Exposure Impact on Infant Health
Drug use during pregnancy has many impacts on the baby’s and mother’s health. Prenatal drug use affects a child’s development during his or her life. When exposed to in utero drug use the baby tends to have a lower birth weight, preterm birth, and intrauterine growth restrictions compared to a baby not exposed to drugs. The number of infants being born with withdrawal to drugs is increasing. This is an important problem because the number of fetuses exposed in utero to drugs is increasing. Research shows that exposure does pose a risk to the fetus and birth outcomes. Finding and implementing interventions to support expecting mothers struggling with drug use is a challenge for medical professionals.https://corescholar.libraries.wright.edu/lake_research_symposium_abstracts/1003/thumbnail.jp
Local dynamics of topological magnetic defects in the itinerant helimagnet FeGe
Chiral magnetic interactions induce complex spin textures including helical
and conical spin waves, as well as particle-like objects such as magnetic
skyrmions and merons. These spin textures are the basis for innovative device
paradigms and give rise to exotic topological phenomena, thus being of interest
for both applied and fundamental sciences. Present key questions address the
dynamics of the spin system and emergent topological defects. Here we analyze
the micromagnetic dynamics in the helimagnetic phase of FeGe. By combining
magnetic force microscopy, single-spin magnetometry, and
Landau-Lifschitz-Gilbert simulations we show that the nanoscale dynamics are
governed by the depinning and subsequent motion of magnetic edge dislocations.
The motion of these topologically stable objects triggers perturbations that
can propagate over mesoscopic length scales. The observation of stochastic
instabilities in the micromagnetic structure provides new insight to the
spatio-temporal dynamics of itinerant helimagnets and topological defects, and
discloses novel challenges regarding their technological usage
Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany
A 0535+26 in the August/September 2005 outburst observed by RXTE and INTEGRAL
In this Letter we present results from INTEGRAL and RXTE observations of the
spectral and timing behavior of the High Mass X-ray Binary A 0535+26 during its
August/September 2005 normal (type I) outburst with an average flux
F(5-100keV)~400mCrab. The search for cyclotron resonance scattering features
(fundamental and harmonic) is one major focus of the paper. Our analysis is
based on data from INTEGRAL and RXTE Target of Opportunity Observations
performed during the outburst. The pulse period is determined. X-ray pulse
profiles in different energy ranges are analyzed. The broad band INTEGRAL and
RXTE pulse phase averaged X-ray spectra are studied. The evolution of the
fundamental cyclotron line at different luminosities is analyzed. The pulse
period P is measured to be 103.39315(5)s at MJD 53614.5137. Two absorption
features are detected in the phase averaged spectra at E_1~45keV and
E_2~100keV. These can be interpreted as the fundamental cyclotron resonance
scattering feature and its first harmonic and therefore the magnetic field can
be estimated to be B~4x10^12G.Comment: 4 pages, 5 figures, accepted for publication in A&A Letter
Assessing Supply Chain Resilience During the Pandemic Using Network Analysis
Disruptions induced by the COVID-19 pandemic have wreaked havoc in supply chain networks. To gain an understanding of the dynamics that had been at play, we construct a real supply chain network (scale-free) based on a seed firm (Apple), its customers, and its first- and second-tier suppliers, yielding a network of a total of 883 firms. We then use visualization to derive insight into various network characteristics and develop an agent-based model to capture the disruption of the network over a period of 400 days from the onset of the pandemic. The disruptions experienced by firms depend on the stringency of measures taken to curb the pandemic in their respective countries and the severity of disruptions experienced by suppliers in a specific region. We specifically find that spatial complexity, degree centrality, betweenness centrality, and closeness centrality have changed significantly throughout our observation period. We thus subsequently theorize on the influence of some of these characteristics on supply chain resilience (SCRes), and through our empirical tests, we find that, at the network level, Average degree and spatial complexity significantly influence SCRes. At the firm-level, we find that powerful firms within the network influence SCRes based on their betweenness centrality and closeness Centrality. Implications for managerial practice and academic research are discussed
A 12-month phase 3 study of pasireotide in cushing's disease
BACKGROUND: Cushing's disease is associated with high morbidity and mortality. Pasireotide, a potential therapy, has a unique, broad somatostatin-receptor-binding profile, with high binding affinity for somatostatin-receptor subtype 5. METHODS: In this double-blind, phase 3 study, we randomly assigned 162 adults with Cushing's disease and a urinary free cortisol level of at least 1.5 times the upper limit of the normal range to receive subcutaneous pasireotide at a dose of 600 ??g (82 patients) or 900 ??g (80 patients) twice daily. Patients with urinary free cortisol not exceeding 2 times the upper limit of the normal range and not exceeding the baseline level at month 3 continued to receive their randomly assigned dose; all others received an additional 300 ??g twice daily. The primary end point was a urinary free cortisol level at or below the upper limit of the normal range at month 6 without an increased dose. Open-label treatment continued through month 12. RESULTS: Twelve of the 82 patients in the 600-??g group and 21 of the 80 patients in the 900-??g group met the primary end point. The median urinary free cortisol level decreased by approximately 50% by month 2 and remained stable in both groups. A normal urinary free cortisol level was achieved more frequently in patients with baseline levels not exceeding 5 times the upper limit of the normal range than in patients with higher baseline levels. Serum and salivary cortisol and plasma corticotropin levels decreased, and clinical signs and symptoms of Cushing's disease diminished. Pasireotide was associated with hyperglycemia-related adverse events in 118 of 162 patients; other adverse events were similar to those associated with other somatostatin analogues. Despite declines in cortisol levels, blood glucose and glycated hemoglobin levels increased soon after treatment initiation and then stabilized; treatment with a glucose-lowering medication was initiated in 74 of 162 patients. CONCLUSIONS: The significant decrease in cortisol levels in patients with Cushing's disease who received pasireotide supports its potential use as a targeted treatment for corticotropin-secreting pituitary adenomas. (Funded by Novartis Pharma; ClinicalTrials.gov number, NCT00434148.) Copyright © 2012 Massachusetts Medical Society
Detection of Topological Spin Textures via Nonlinear Magnetic Responses
Topologically nontrivial spin textures, such as skyrmions and dislocations, display emergent electrodynamics and can be moved by spin currents over macroscopic distances. These unique properties and their nanoscale size make them excellent candidates for the development of next-generation race-track memory and unconventional computing. A major challenge for these applications and the investigation of nanoscale magnetic structures in general is the realization of suitable detection schemes. We study magnetic disclinations, dislocations, and domain walls in FeGe and reveal pronounced responses that distinguish them from the helimagnetic background. A combination of magnetic force microscopy (MFM) and micromagnetic simulations links the response to the local magnetic susceptibility, that is, characteristic changes in the spin texture driven by the MFM tip. On the basis of the findings, which we explain using nonlinear response theory, we propose a read-out scheme using superconducting microcoils, presenting an innovative approach for detecting topological spin textures and domain walls in device-relevant geometries
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