4,306 research outputs found
Mapping the Universe Expansion: Enabling percent-level measurements of the Hubble Constant with a single binary neutron-star merger detection
The joint observation of the gravitational-wave and electromagnetic signal from the binary neutron-star merger GW170817 allowed for a new independent measurement of the Hubble constant , albeit with an uncertainty of about 15\% at 1. Observations of similar sources with a network of future detectors will allow for more precise measurements of . These, however, are currently largely limited by the intrinsic degeneracy between the luminosity distance and the inclination of the source in the gravitational-wave signal. We show that the higher-order modes in gravitational waves can be used to break this degeneracy in astrophysical parameter estimation in both the inspiral and post-merger phases of a neutron star merger. We show that for systems at distances similar to GW170817, this method enables percent-level measurements of with a single detection. This would permit the study of time variations and spatial anisotropies of with unprecedented precision. We investigate how different network configurations affect measurements of , and discuss the implications in terms of science drivers for the proposed 2.5- and third-generation gravitational-wave detectors. Finally, we show that the precision of measured with these future observatories will be solely limited by redshift measurements of electromagnetic counterparts
Processing of strong flux trapping high T(subc) oxide superconductors: Center director's discretionary fund
Magnetic suspension effect was first observed in samples of YBa2Cu3O7/AgO(Y-123/AgO) composites. Magnetization measurements of these samples show a much larger hysteresis which corresponds to a large critical current density. In addition to the Y-123AgO composites, recently similar suspension effects in other RE-123/AgO, where RE stands for rare-Earth elements, were also observed. Some samples exhibit even stronger flux pinning than that of the Y-123/AgO sample. An interesting observation was that in order to form the composite which exhibits strong flux trapping effect the sintering temperature depends on the particular RE-123 compound used. The paper presents the detailed processing conditions for the formation of these RE-123/AgO composites, as well as the magnetization and critical field data
Robotic simulators for tissue examination training with multimodal sensory feedback
Tissue examination by hand remains an essential technique in clinical practice. The effective application depends on skills in sensorimotor coordination, mainly involving haptic, visual, and auditory feedback. The skills clinicians have to learn can be as subtle as regulating finger pressure with breathing, choosing palpation action, monitoring involuntary facial and vocal expressions in response to palpation, and using pain expressions both as a source of information and as a constraint on physical examination. Patient simulators can provide a safe learning platform to novice physicians before trying real patients. This paper reviews state-of-the-art medical simulators for the training for the first time with a consideration of providing multimodal feedback to learn as many manual examination techniques as possible. The study summarizes current advances in tissue examination training devices simulating different medical conditions and providing different types of feedback modalities. Opportunities with the development of pain expression, tissue modeling, actuation, and sensing are also analyzed to support the future design of effective tissue examination simulators
Sub-Nyquist Field Trial Using Time Frequency Packed DP-QPSK Super-Channel Within Fixed ITU-T Grid
Sub-Nyquist time frequency packing technique was demonstrated for the first
time in a super channel field trial transmission over long-haul distances. The
technique allows a limited spectral occupancy even with low order modulation
formats. The transmission was successfully performed on a deployed Australian
link between Sydney and Melbourne which included 995 km of uncompensated SMF
with coexistent traffic. 40 and 100 Gb/s co-propagating channels were
transmitted together with the super-channel in a 50 GHz ITU-T grid without
additional penalty. The super-channel consisted of eight sub-channels with
low-level modulation format, i.e. DP-QPSK, guaranteeing better OSNR robustness
and reduced complexity with respect to higher order formats. At the receiver
side, coherent detection was used together with iterative maximum-a-posteriori
(MAP) detection and decoding. A 975 Gb/s DP-QPSK super-channel was successfully
transmitted between Sydney and Melbourne within four 50GHz WSS channels (200
GHz). A maximum potential SE of 5.58 bit/s/Hz was achieved with an OSNR=15.8
dB, comparable to the OSNR of the installed 100 Gb/s channels. The system
reliability was proven through long term measurements. In addition, by closing
the link in a loop back configuration, a potential SE*d product of 9254
bit/s/Hz*km was achieved
A novel approach for the preparation of nanosized Gd2O3 structure: The influence of surface force on the morphology of ball milled particles
This work investigates the effect of inter-particle forces arising from adsorbed typical cationic and anionic surfactants on the morphology of ball milled gadolinium oxide (Gd2O3). The experimental outcomes are interpreted in terms of stabilization and interaction mechanisms of fine washed Gd2O3 particles (size diameter 2O3 particles suspension is at pH 11 where its maximum yield stress is observed. Because of hydrophobic interaction, the maximum yield stress increases by 30 times by adsorbed sodium dodecyl sulfate (SDS) and its IEP shifts slightly to a lower pH. By cetyl trimethyl ammonium bromide (CTAB), the yield stress also increases by a much smaller extent (3 times) and shifts to a higher pH of ∼12.5. Without surfactants, the microstructure of dried Gd2O3 displays the coarse particles of various shapes, i.e. rod, spherical and cubic shapes. This indicates that the milled particles remain agglomerated in dispersion. In the presence of adsorbed anionic SDS, the particles are refined together with numerous 2D nanowire or nano-rod particles at pH ∼ 8. In contrast, coarser particles with absence of nano-rods are found when cationic CTAB is used to modify the Gd2O3 surface at a pH of about 12.5. The SDS-modified suspension exhibits a much higher yield stress, which results from finer particles in suspension. This is invoked from an organic shell formed by the high adsorbability of negatively charged heads of SDS into the bare positive charge density of the particle. The organic SDS shell prevents the fine particles from re-welding during the dispersing and annealing route. This work develops an inexpensive ball-milling approach with assisted SDS surfactant for mass production of nanosized Gd2O3 from bulky gadolinium material
In depth analysis of the Sox4 gene locus that consists of sense and natural antisense transcripts
Available online 17 February 2016SRY (Sex Determining Region Y)-Box 4 or Sox4 is an important regulator of the pan-neuronal gene expression during post-mitotic cell differentiation within the mammalian brain. Sox4 gene locus has been previously characterized with multiple sense and overlapping natural antisense transcripts [1], [2]. Here we provide accompanying data on various analyses performed and described in Ling et al. [2]. The data include a detail description of various features found at Sox4 gene locus, additional experimental data derived from RNA-Fluorescence in situ Hybridization (RNA-FISH), Western blotting, strand-specific reverse-transcription quantitative polymerase chain reaction (RT-qPCR), gain-of-function and in situ hybridization (ISH) experiments. All the additional data provided here support the existence of an endogenous small interfering- or PIWI interacting-like small RNA known as Sox4_sir3, which origin was found within the overlapping region consisting of a sense and a natural antisense transcript known as Sox4ot1.King-Hwa Ling, Peter J. Brautigan, Sarah Moore, Rachel Fraser, Melody Pui-Yee Leong, Jia-Wen Leong, Shahidee Zainal Abidin, Han-Chung Lee, Pike-See Cheah, Joy M. Raison, Milena Babic, Young Kyung Lee, Tasman Daish, Deidre M. Mattiske, Jeffrey R. Mann, David L. Adelson, Paul Q. Thomas, Christopher N. Hahn, Hamish S.Scot
Electrochemical capacitance of a leaky nano-capacitor
We report a detailed theoretical investigation on electrochemical capacitance
of a nanoscale capacitor where there is a DC coupling between the two
conductors. For this ``leaky'' quantum capacitor, we have derived general
analytic expressions of the linear and second order nonlinear electrochemical
capacitance within a first principles quantum theory in the discrete potential
approximation. Linear and nonlinear capacitance coefficients are also derived
in a self-consistent manner without the latter approximation and the
self-consistent analysis is suitable for numerical calculations. At linear
order, the full quantum formula improves the semiclassical analysis in the
tunneling regime. At nonlinear order which has not been studied before for
leaky capacitors, the nonlinear capacitance and nonlinear nonequilibrium charge
show interesting behavior. Our theory allows the investigation of crossover of
capacitance from a full quantum to classical regimes as the distance between
the two conductors is changed
Radion and Holographic Brane Gravity
The low energy effective theory for the Randall-Sundrum two brane system is
investigated with an emphasis on the role of the non-linear radion in the brane
world. The equations of motion in the bulk is solved using a low energy
expansion method. This allows us, through the junction conditions, to deduce
the effective equations of motion for the gravity on the brane. It is shown
that the gravity on the brane world is described by a quasi-scalar-tensor
theory with a specific coupling function omega(Psi) = 3 Psi / 2(1-Psi) on the
positive tension brane and omega(Phi) = -3 Phi / 2(1+Phi) on the negative
tension brane, where Psi and Phi are non-linear realizations of the radion on
the positive and negative tension branes, respectively. In contrast to the
usual scalar-tensor gravity, the quasi-scalar-tensor gravity couples with two
kinds of matter, namely, the matters on both positive and negative tension
branes, with different effective gravitational coupling constants. In
particular, the radion disguised as the scalar fields Psi and Phi couples with
the sum of the traces of the energy momentum tensor on both branes. In the
course of the derivation, it has been revealed that the radion plays an
essential role to convert the non-local Einstein gravity with the generalized
dark radiation to the local quasi-scalar-tensor gravity. For completeness, we
also derive the effective action for our theory by substituting the bulk
solution into the original action. It is also shown that the
quasi-scalar-tensor gravity works as holograms at the low energy in the sense
that the bulk geometry can be reconstructed from the solution of the
quasi-scalar-tensor gravity.Comment: Revtex4, 18 pages, revised version, conclusions unchanged, references
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Cost-benefit analysis for commissioning decisions in GEO600
Gravitational wave interferometers are complex instruments, requiring years
of commissioning to achieve the required sensitivities for the detection of
gravitational waves, of order 10^-21 in dimensionless detector strain, in the
tens of Hz to several kHz frequency band. Investigations carried out by the
GEO600 detector characterisation group have shown that detector
characterisation techniques are useful when planning for commissioning work. At
the time of writing, GEO600 is the only large scale laser interferometer
currently in operation running with a high duty factor, 70%, limited chiefly by
the time spent commissioning the detector. The number of observable
gravitational wave sources scales as the product of the volume of space to
which the detector is sensitive and the observation time, so the goal of
commissioning is to improve the detector sensitivity with the least possible
detector down time. We demonstrate a method for increasing the number of
sources observable by such a detector, by assessing the severity of
non-astrophysical noise contaminations to efficiently guide commissioning. This
method will be particularly useful in the early stages and during the initial
science runs of the aLIGO and adVirgo detectors, as they are brought up to
design performance.Comment: 17 pages, 17 figures, 2 table
Classifying multi-level stress responses from brain cortical EEG in Nurses and Non-health professionals using Machine Learning Auto Encoder
ObjectiveMental stress is a major problem in our society and has become an area of interest for many psychiatric researchers. One primary research focus area is the identification of bio-markers that not only identify stress but also predict the conditions (or tasks) that cause stress. Electroencephalograms (EEGs) have been used for a long time to study and identify bio-markers. While these bio-markers have successfully predicted stress in EEG studies for binary conditions, their performance is suboptimal for multiple conditions of stress.MethodsTo overcome this challenge, we propose using latent based representations of the bio-markers, which have been shown to significantly improve EEG performance compared to traditional bio-markers alone. We evaluated three commonly used EEG based bio-markers for stress, the brain load index (BLI), the spectral power values of EEG frequency bands (alpha, beta and theta), and the relative gamma (RG), with their respective latent representations using four commonly used classifiers.ResultsThe results show that spectral power value based bio-markers had a high performance with an accuracy of 83%, while the respective latent representations had an accuracy of 91%
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