6,231 research outputs found
Curvaton Scenario with Affleck-Dine Baryogenesis
We discuss the curvaton scenario with the Affleck-Dine baryogenesis. In this
scenario, non-vanishing baryonic entropy fluctuation may be generated even
without primordial fluctuation of the Affleck-Dine field. Too large entropy
fluctuation is inconsistent with the observations and hence constraints on the
curvaton scenario with the Affleck-Dine baryogenesis are obtained. We calculate
the baryonic entropy fluctuation (as well as other cosmological density
fluctuations) in this case and derive constraints. Implications to some of the
models of the curvaton are also discussed.Comment: 16 pages,2 figure
Dynamic range of nanotube- and nanowire-based electromechanical systems
Nanomechanical resonators with high aspect ratio, such as nanotubes and nanowires are of interest due to their expected high sensitivity. However, a strongly nonlinear response combined with a high thermomechanical noise level limits the useful linear dynamic range of this type of device. We derive the equations governing this behavior and find a strong dependence [[proportional]dsqrt((d/L)[sup 5])] of the dynamic range on aspect ratio
The Past Has Ears (PHE): XR Explorations of Acoustic Spaces as Cultural Heritage
Hearing is one of our most pervasive senses. There is no
equivalent to closing our eyes, or averting our gaze, for the ears. When
we think about great architectural achievements in European history,
such as ancient amphitheatres or Gothic cathedrals, their importance
is strongly tied to their acoustic environment. The acoustics of a heritage
site is an intangible consequence of the space's tangible construction
and furnishings. Inspired by the project's namesake (Phe, for the
constellation Phoenix), and the relatively recent res at Cathedrale de
Notre Dame de Paris and Teatro La Fenice opera hall, the PHE project
focuses on virtual reconstruction of heritage sites, bringing them back
from the ashes. In addressing the intangible acoustic heritage of architectural
sites, three main objectives have been identied for this research
project: Documentation, Modelling, and Presentation. In parallel, three
heritage sites are participating as case studies: Tindari Theatre (IT),
Notre-Dame de Paris Cathedral (FR), and The Houses of Parliament
(UK). The acoustics of a space is immersive, spatial, and due to the nature
of auditory perception egocentric, in contrast to visual perception
of an object, which can be observed from outside". Consequently, presentation
methods for communicating acoustic heritage must represent
the spatially immersive and listener-centric nature of acoustics. PHE will
lead development of a museum grade hardware/software prototype for
the presentation of immersive audio experiences adaptable to multiple
platforms, from on-site immersive speaker installations, to mobile XR
via smartphone applications
Nanowire-based very-high-frequency electromechanical resonator
Fabrication and readout of devices with progressively smaller size, ultimately down to the molecular scale, is critical for the development of very-high-frequency nanoelectromechanical systems (NEMS). Nanomaterials, such as carbon nanotubes or nanowires, offer immense prospects as active elements for these applications. We report the fabrication and measurement of a platinum nanowire resonator, 43 nm in diameter and 1.3 µm in length. This device, among the smallest NEMS reported, has a fundamental vibration frequency of 105.3 MHz, with a quality factor of 8500 at 4 K. Its resonant motion is transduced by a technique that is well suited to ultrasmall mechanical structures
Effect of breastfeeding promotion interventions on cost-effectiveness of rotavirus immunization in Indonesia
BACKGROUND: Rotavirus infection has been reported to be responsible for the majority of severe diarrhea in children under-5-years-old in Indonesia. Breast milk is considered to give protection against rotavirus infection. Increasing breastfeeding promotion programs could be an alternative target to reduce the incidence of rotavirus diarrhea. This study aims to investigate the effect of breastfeeding promotion interventions on cost-effectiveness of rotavirus immunization in Indonesia, focusing on breastfeeding education and support interventions.METHODS: An age-structured cohort model was developed for the 2011 Indonesia birth cohort. We compared four interventions in scenarios: (i) base-case (I₀) reflecting the current situation for the population of under-5-years-old, (ii) with an additional breastfeeding education intervention (I₁), (iii) with a support intervention on initiation and duration (I₂) and (iv) with both of these two interventions combined (I₃). The model applied a 5-years time horizon, with 1 month analytical cycles for children less than 1 year of age and annually thereafter. Monte Carlo simulations were used to examine the economic acceptability and affordability of rotavirus vaccination.RESULTS: Rotavirus immunization would effectively reduce severe cases of rotavirus during the first 5 years of a child's life even assuming various breastfeeding promotion interventions. The total yearly vaccine cost would amount to US 153 per quality-adjusted-life-year (societal perspective) with an optimal breastfeeding promotion intervention. Obviously, this is much lower than the 2011 Gross Domestic Product (GDP) per capita of US$ 3,495. Affordability results showed that at the market vaccine price, rotavirus vaccination could be affordable for the Indonesian health system.CONCLUSIONS: Rotavirus immunization would be a highly cost-effective public health intervention for Indonesia even under various breastfeeding promotion interventions based on the WHO's criteria for cost-effectiveness in universal immunization.</p
Muon Pair Production by Electron-Photon Scatterings
The cross section for muon pair productions by electrons scattering over
photons, , is calculated analytically in the leading order. It is
pointed out that for the center-of-mass energy range, ,
the cross section for is less than b. The differential
energy spectrum for either of the resulting muons is given for the purpose of
high-energy neutrino astronomy. An implication of our result for a recent
suggestion concerning the high-energy cosmic neutrino generation through this
muon pair is discussed.Comment: a comment added, to appear in Phys. Rev. D, Rapid Communicatio
Basins of attraction of a nonlinear nanomechanical resonator
We present an experiment that systematically probes the basins of attraction
of two fixed points of a nonlinear nanomechanical resonator and maps them out
with high resolution. We observe a separatrix which progressively alters shape
for varying drive strength and changes the relative areas of the two basins of
attraction. The observed separatrix is blurred due to ambient fluctuations,
including residual noise in the drive system, which cause uncertainty in the
preparation of an initial state close to the separatrix. We find a good
agreement between the experimentally mapped and theoretically calculated basins
of attraction
An extendable modular endoprosthetic system for bone tumour management in the leg
A modular endoprosthetic system has been developed at the Groningen University Hospital and the University of Twente. The system can bridge a defect resulting from the resection of a malignant bone tumour which has developed around the knee joint of a child. Since the other healthy leg continues to grow, the system includes an element whose length can be adjusted non-invasively by using an external magnetic field. In addition to this lengthening element, there are one hip and two knee components, connectors of various lengths, and fixation elements. The paper describes the elements of the modular endoprosthetic system. Tables are created by means of which the elemental composition of such an endoprosthesis can be determined for each individual patient
Genomic alterations in primary gastric adenocarcinomas correlate with clinicopathological characteristics and survival.
Background & aimsPathogenesis of gastric cancer is driven by an accumulation of genetic changes that to a large extent occur at the chromosomal level. In order to investigate the patterns of chromosomal aberrations in gastric carcinomas, we performed genome-wide microarray based comparative genomic hybridisation (microarray CGH). With this recently developed technique chromosomal aberrations can be studied with high resolution and sensitivity.MethodsArray CGH was applied to a series of 35 gastric adenocarcinomas using a genome-wide scanning array with 2275 BAC and P1 clones spotted in triplicate. Each clone contains at least one STS for linkage to the sequence of the human genome. These arrays provide an average resolution of 1.4 Mb across the genome. DNA copy number changes were correlated with clinicopathological tumour characteristics as well as survival.ResultsAll thirty-five cancers showed chromosomal aberrations and 16 of the 35 tumours showed one or more amplifications. The most frequent aberrations are gains of 8q24.2, 8q24.1, 20q13.12, 20q13.2, 7p11.2, 1q32.3, 8p23.1-p23.3, losses of 5q14.1, 18q22.1, 19p13.12-p13.3, 9p21.3-p24.3, 17p13.1-p13.3, 13q31.1, 16q22.1, 21q21.3, and amplifications of 7q21-q22, and 12q14.1-q21.1. These aberrations were correlated to clinicopathological characteristics and survival. Gain of 1q32.3 was significantly correlated with lymph node status (p=0.007). Tumours with loss of 18q22.1, as well as tumours with amplifications were associated with poor survival (p=0.02, both).ConclusionsMicroarray CGH has revealed several chromosomal regions that have not been described before in gastric cancer at this frequency and resolution, such as amplification of at 7q21-q22 and 12q14.1-q21.1, as well gains at 1q32.3, 7p11.2, and losses at 13q13.1. Interestingly, gain of 1q32.3 and loss of 18q22.1 are associated with a bad prognosis indicating that these regions could harbour gene(s) that may determine aggressive tumour behaviour and poor clinical outcome
Longevity of supersymmetric flat directions
We examine the fate of supersymmetric flat directions. We argue that the
non-perturbative decay of the flat direction via preheating is an unlikely
event. In order to address this issue, first we identify the physical degrees
of freedom and their masses in presence of a large flat direction VEV (Vacuum
Expectation Value). We explicitly show that the (complex) flat direction and
its fermionic partner are the only light {\it physical} fields in the spectrum.
If the flat direction VEV is much larger than the weak scale, and it has a
rotational motion, there will be no resonant particle production at all. The
case of multiple flat directions is more involved. We illustrate that in many
cases of physical interest, the situation becomes effectively the same as that
of a single flat direction, or collection of independent single directions. In
such cases preheating is not relevant. In an absence of a fast non-perturbative
decay, the flat direction survives long enough to affect thermalization in
supersymmetric models as described in hep-ph/0505050 and hep-ph/0512227. It can
also ``terminate'' an early stage of non-perturbative inflaton decay as
discussed in hep-ph/0603244.Comment: 9 revtex pages, v3: expanded discussion on two flat directions, minor
modifications, conclusions unchange
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